aj mccormack and son

Block Paving - Page 06
The Brew Cabin
block paving


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Forum Question Recess trays - Nashy - 7 September 2002
I require a recess tray for a square waste drain.The internal measurements are 600mm by 760mm,can only find 600mm by 600mm. Have yet to see recess tray in the flesh and suspect i could be measuring wrong.
Back to the tray i suspect the internal area is 600mm by 600mm but the overall length including the lip should take me upto 760mm?


forum answer Tony McCormack - 8 September 2002
You can 'corbel' the opening, ie, reduce it in size, so that a standard 600x600mm recess tray is suitable as a cover. This can be done with bricks (engineering type), or with hydraulically pressed concrete flags/edging kerbs, with steel lintels or similar.

However, you can get different sizes of trays, from specialist suppliers, but you will pay quite a premium for them. If poss, it's always cheaper to stick with a 600x600 than to hunt down and fork out 120+ quid for a 600x750mm tray.

Are you ok on the principle of corbelling, or do you need me to explain it further?

8 September 2002
Tony McCormack
8 September 2002
There's a diagram on the Recess Trays page showing the priinciple of corbelling - about three-quarters of the way down the page.

If I get the time later on, I'll see if I can come up with a better drawing, but for now, the basic premise is that each successive course of bricks projects out a little bit more, gradually reducing the opening to the required width.

You can use hydraulically pressed flags or edging kerbs, in place of the bricks, if you prefer.

Forum Question Commercial paving - Suki - 8 September 2002
Hi tony hope u are well, we have been asked to do a commercial job, so far we have only done private driveways etc... which are fairly straight forward issues however we have now been asked to block pave in front of 10 shop fronts the dimensions are 250ft x 70ft and will be trafficked by trucks as well as cars now i figure on using 10 inches of mot and a 80mm block is this too much or to little, as well as that do u have any tips for us when working on a public highway as this is new territory for us (if we get the job that is we have quoted and have been told we are well in the running) ps.. how much would u say is the going rate for that size job???  if we get the job i will send u some piccys of the job before we start.
forum answer Tony McCormack
9 September 2002
If this really is a public highway, you need lots of insurance, possibly 5 million, and you'll need clearance from the Local Authority, who will probably ask for Streetworks Accreditation. You will also have to make allowances for mandatory Safety measures, site fencing, signage, identification of services etc.

I'm not trying to put you off, but working on a public highway is much more onerous than working on a private driveway, just in terms of the legislation - the work itself, ie, actually laying the blocks, is more or less the same, but the can make a grown man weep!

It's not possible to give an off-the-shelf spec for a public highway job. The LA will have a spec, but I should imagine it will involve 250-300mm of granular sub-base or a 150mm CBM3 base layer, and then an 80mm block.

Are you sure this is a public highway? If it's actually a private shop frontage, then the spec could be down to you and the Elf&Safety requirements are less onerous, but you need to check this first.

9 September 2002
thx for the prompt relpy tony and yes u are right i have checked and they are private frontages that the shops want to basically convert into parking (as there are lots of double yellows and only room for 8 cars to park at the moment) for there customers they reckon they can get over fifty cars parked in there once its paved however there will be some delevery trucks using it to drop off to the shops, so thats what i know so far oh and one quicky, Cement Bound Material 3??
Tony McCormack
10 September 2002
CBM3 is explained on the Sub-bases page.

Have you been given a design/spec or is this a design and build contract? Is there an existing crossing of the footpath? Is it a full and proper contract (eg ICE or JCT Minor Works) or is it a 'quote and go' job?

I f they've put the job out to tender, they really should have a design so that all contractors are pricing the same work. If they are looking for a Design and Build project, then you will need to ensure any design you submit/construct is technically suitable and that you're fully insured with Contractors All Risk, otherwise....well, it can get a bit scarey if you're not familiar with commercial contracting and all the potential pitfalls.

I'm not trying to put you off, but I would strongly recommend you speak to a QS, a Highways Engineer or someone in the know who is familiar with the site. If you Design and Build, will you be liable for any defects? Will there be a defects period and a retention? Questions such as this ultimately affect the price of the job.

Give me a call if you're stuck - best between 12 noon and 4pm, or after 7pm, as that's when I'm at my best with the painkillers.

10 September 2002
thx tony for the sound advice i will keep u posted on this one smiley
Forum Question Soft sub grade - Deefa - 12 September 2002
Hi Tony, i,m in the process of laying a new block paved pathway and patio in my back garden, i have excavated down the required amount but i have found that a small section (approx 2sq meters) is as soft as a trifle!, although this soft part of the sub grade falls under the path area i am worried about its effects on differential settlement and am wondering the best way round the problem, i have considered digging out more of the soil in this area until i hopefully hit a more substantial base and then backfilling the hole with m.o.t? also i have read your section concerning geomembrane??..not sure mate so i thought i,d ask the man himself!
forum answer Tony McCormack - 13 September 2002
Excavate the soft spot. Although there can be many reasons for the existence of soft spots as you describe, it's important to establish that it's not come about because of a leaky water service pipe or a leaky drain. This should become apparent once you've dug down another 2-300mm or so - if it's a water/drain problem, the ground will get wetter and wetter; if it's just a soft spot of no cause, it will start to firm up.

Assuming it is just an isolated dollop of softer material, once it's excavated, you can backfill with Type 1 material, compacting in layers no greater than 150mm until you're back at formation level for the rest of the paving.

It may be worth putting down a genuine separation membrane,such as Terram (not a weed membrane such as Plantex), and then building up your sub-base as per normal. I would probably take this route, given the existence of one identified soft spot and the uncertain nature of the rest of the ground.

You only want to be laying the block paving once, so you might as well get it right. smiley

16 September 2002
hi tony, well the mysterious trifle patch seems to have sorted itself out!!, after returning to the job on monday the ground is now rock solid and seems ok to lay the sub base onto?? the block paving gods seem to be smiling on us on this one mate
Tony McCormack
17 September 2002
It sounds as though the dry weather has firmed it up, but it's probably still worth using a membrane, for when the damp returns.
Forum Question Moss & weeds - PaulH - 22 September 2002
We moved to our house about a year ago and it has a lovely blocked paved drive, probably done about 4/5 years ago. It was a bit grimy and dirty so I used a pressure washer to clean it earlier this year.
I have replaced the sand between the blocks, but still have a recurring problem with moss and weeds! Can anyone recommed a treatment (available at B&Q or Homebase perhaps) that will kill them off for me?
forum answer Tony McCormack - 22 September 2002
Any good weedkiller will do, but it's not a permanent solution. We normally use Sodium Chlorate, because it's cheap, it's available in bulk and it works, but you could use 'PathClear' or 'Weedol' or anything like that. Generally speaking, a treatment will last for about 2-3 months during the growing season, so you'd need to treat in, say, March, early June and again in September.

For a permanent solution, the only real option is to use a paving sealant, and for that, your paving needs to be in tip-top condition before you apply the first coat; that means clearing all the weeds, giving the entire pavement a damn good cleaning with the power washer (at a shallow angle, of course! ) and have all the joints topped up with jointing sand.

23 September 2002
I have tried weedol, but it didn't seem to be very effective.
I had heard about Pathclear. Might give that a go.
Forum Question Marking paver stones for cutting - Joecontrol - 29 September 2002
I have to mark MANY stones for finishing my patio (circular with circular center feature). Are there any tricks to making accurate marks for cuts?
forum answer Tony McCormack - 29 September 2002
It seems every contractor has their own favourite way of marking blocks for cuts. Some measure using a tape, which we find time-consuming and slow. Others have an adjustable profile guide, but these are less than accurate and again, slow down progress. The method we have used for 20-odd years, and the way we teach all our trainees, is to align the block in position over the gap, learn to align your eye directly above the cut line, and then use the edge of a shard of slate to mark the block 3-6mm short, so that, allowing for the joint widths, it drops in the gap neatly.

It really is just a matter of practice. Some lads and lasses pick it up in an hour; some can be at it a week and still not get it, but that's human nature for you.

I had to amend some paving on my driveway a couple of weeks ago, to make rooom for a new rose bush, and so I took a couple of pics as I was marking up the blocks for cutting - I had to get my son to cut them for me, as my knackered spine won't allow me to operate the splitter any longer, but at least I've not lost the knack of 'eyeing-in' the cuts.  smiley

Here's one of the pics that was/is going to be added to the Cutting Blocks page, as soon as I get the time.

marking blocks for cutting

Forum Question Tarmac being buried under sub-base? - rspecial - 1 October 2002
This is a great site and very informative. I am having a block paved driveway done at this very monent and the contractor has used some of the old tarmac beneath the sub-base. He dug out the depth well beyond 200mm, removing a lot of heavy clay in the process. He has used some of the old tarmac drive beneath the sub-base which is at least 100mm of type 1. Does this sound reasonable? In a few places there is are some chunks of tarmac mixed in with the Type 1, but generally it seems to be pretty consistent across the whole area.

Has he done the right thing removing clay and replacing it with old tarmac, or is he just avoiding having too much tarmac to dispose of? He took away most of the old tarmac away anyway so I cant think of any sinister reasons for what he has done. Advice welcomed, he's coming back tomorrow to do the edging...

forum answer Tony McCormack - 1 October 2002
It's a little bit naughty to use old bitmac as a fill layer, as it does degrade over time, but, for a residential driveway, it should be ok, as long as it hasn't been used to skimp on the actual sub-base, and doesn't protrude into the bedding layer.

It should have been broken up into 'chunks' no bigger than 50mm and evenly spread over the exposed sub-grade as what we call a 'capping layer'. I suppose the contractor has elected to use it to replace some soft clay or other suspect sub-grade material, which is better than leaving the iffy stuff in place, but not as good as building-up with genuine sub-base material or using a geo-membrane.

Depending on how the excavated material is being disposed, it can be cheaper to send inert clay to the landfill, than to send old bitmac, as that is NOT inert and has to be treated as degradable waste, attracting a higher level of landfill tax. Some companies charge a standard rate for all waste; others charge less for inert. So, maybe your contractor is being a little bit clever (they'll probably call it "environmentally friendly" ) by sending the clay to the tip, rather than bitmac.

As long as you're getting an insurance-backed written guarantee, there's probably nowt to worry about.

1 October 2002
Thanks for the prompt reply - its really useful and I spoke to the contractor after reading it. He did use the tarmac to make up a small area of poor subsoil where the original house builders had dumped a load of broken up clay/rubbish etc. He assures me he put a good layer of type 1 on top and certainly used a big wacker to compress it all so all should be fine smiley
Forum Question Contractor needed - Plugus Maximus - 23 October 2002
I have made a start on trying(!) to lay a block paved front garden to my small terraced house. Only I've bottled it and need some professional assistance. I've excavated the area and sort of layed some hardcore and that's about it! Can anyone recommend a local tradesman to finish of the job? I also wouldn't mind assisting/watching so I too can learn from an expert. If you can recommend a good quality/relaible/cheap(!) :)paver please let me know

Thanks for any help you can offer ...

Kevin Holland

forum answer Tony McCormack - 23 October 2002
You could try...

tel: 0207 359 3582
fax: 07092 118 736


Scott Marsom @ Canvey Island 0800 975 7175


Eurobright Construction Ltd.
36 Gresham Road, Custom House, LONDON. E16 3DU
Tel: 020 7473 5491
Fax: 020 7473 5491


Graystone Paving
4 Sheldon Avenue, Clayhall, Ilford, Essex. IG5 0UG
Tel: 020 8550 7510
Fax: 020 8550 2822

Hope that helps. smiley

Forum Question Block Paving drainage on concrete base - Boggie - 25 October 2002
I am laying block paving for off street parking in front of my house. As the land is clay I decided to put the blocks on a 100mm concrete platform. I have now finished this and am planning to put soft sand (no cement) down to bed the blocks. My question is this:-

Will rainwater drain away through the sand between and under the blocks and run off the concrete platform edge as I planned or will I need a canoe to get between the car and house?

forum answer Tony McCormack - 25 October 2002
Firstly, I don't understand why you've elected to use a concrete base layer, but that's by the by at this stage. Secondly, you should not lay the blocks on soft sand, but on GRIT sand. It may seem a minor detail to you, but the way these sands behave under loading determines whether your paving lasts longer than one season.

Turning to the drainage, any water penetrating the pavement will become trapped between the concrete base layer and the paving layer, and so there must be some 'escape route'. This may be off the edge of the concrete, as you hope, but that, ultimately, depends on what the ground is like at that point. If it's solid, impermeable clay, then you could be making a problem for yourself: the laying course (the grit sand discussed above) [b]must[/b] be able to drain to perform properly.

With concrete (CBM) or bitmac base layers (DBM), it's usual practice to incorporate some form of drainage within or directly adjacent to the base layer to ensure the laying course is adequately drained. This may be a fin drain or a length of land drain, but some provision is made, otherwise the laying course saturates, becomes fluid under load, and the paving starts to move. sulk

So; what's the ground like next to the concrete base? Will it provide adequate drainage or do you think you'll need to install a land drain?

26 October 2002
Hi Tony,
Cheers for the prompt reply. The concrete base has clay soil topped with tarmac at the entrance to the parking area, a wall with foundations on the right and clay soil with a path made from paving slabs on the left. All these surfaces would inhibit drainage as they are level with the block surface. However at the lowest edge of the concrete base there is a 1 foot gap between it and the front of the house which is an existing concrete path about 8 inches lower than the parking area. This effectively creates a concrete channel which has a surface water drainage grid at one end. This is where I intend to drain the water from under the blocks after it filters it's way through the grit sand (thanks for the tip)
Does this sound like it will work.

P.S. I got the advice (of using a 100mm concrete base as opposed to hardcore on clay soil) from the B&Q website.
Maybe they are being a little over zealous.

Tony McCormack
27 October 2002
Your drainage plan sounds ok, as long as it's not going to rest against the house or breach DPCs. However, from what you've described, I still can't see why a CBM base is required when a standard granular sub-base would be more than adequate.

As for B&Q, that well known firm of block paving specialists - I'd be much happier if they left the construction advice to professionals. If I promise not to sell cheap doors and light fittings, will they promise to leave off the crap advice?

The trouble with many of these 'suppliers', and some of the manufacturers, is that when they are asked for advice, because their insurers have scared the pants off them with regard to liability, they tend to go for a spec that is way, way, way over the top. They should stick to what they do best - flogging materials - and not try to be all things to all people. smiley

28 October 2002
Point taken. Next time I know where I will look, unfortunately I only discovered this forum after finding and following their advice.

Great site, excellent resource

Richard Malin
31 October 2002
Hi lads,
I just read the B+Q "advice" as well.
Just what on earth do they think you are going to park on your drive after you've done it their way?
A Volvo FH16? A chieftain tank? Or a fully loaded Boeing 747 cargo plane?
I lay blocks for a living and just use 4" of good old type one and plain sharp sand, perhaps a bit more stone if the ground seems suspect - and we haven't had any sinkages yet!
I'll go to B+Q and tell them off.
Tony McCormack
1 November 2002
Have you ever attended one of their 'How To' lectures that they hold in the Warehouse Stores some evenings? Ber-luddy hell fire!! I nearly smacked the paving demonstrator for telling me to "leave advice to the professionals, sir", when I asked why he was telling the handful of folk watching his efforts that using a spadeful of cement  with the jointing sand would make their block paving more solid.


7 November 2002
Now that I would have liked to see!

- Mike -

Forum Question How much grit and silica sand? - Boggie - 30 October 2002
I am planning to lay paving blocks over an 18 square meter drive. I have the base complete and need to know how much grit sand to order for the bedding layer and how much silica sand I will need to brush down the gaps.
forum answer Tony McCormack - 30 October 2002
2 tonnes of grit sand and 2 bags of the jointing sand (40kg bags) should do it.

There's a spreadsheet for calculating all these quantities on the Introductory Block Paving page. smiley

30 October 2002
Thanks Tony,
I will get on to my local merchant.
One thing I have noticed with todays heavy rain, there is a shallow puddle slightly off from center. It's about half an inch deep and about the size of a flagstone but if it gets any deeper it will drain off the edge. Is this a problem or am I ok to lay the bedding sand and blocks?
Tony McCormack
31 October 2002
|I take it this is a puddle on the base that you intend to pave over? If so, don't worry about it - chase out any standing water with a yard brush before placing and preparing the laying course, just so it doesn't get saturated. smiley
31 October 2002
Cheers Tony,
I seems I've been a bit thick as I was assuming that surface water drains between the blocks through the sand then runs off the concrete base at the edge. Thats why I was worried about failing to get the base to drain properly as I was imagining a permanent puddle under the blocks. Obviously I just need to make sure the the blocks are set so they drain where I want.
Thanks again.
Tony McCormack
1 November 2002
It's not just you - it's a common misconception that surface water drains through the joints of a block pavement when, in fact, over 98% of surface water never gets more than 3mm into the surface of the pavement. Howver, the laying course still needs to drain, so it's good practice to ensure you're not creating a 'pond' beneath the pavement.
Forum Question Paving in the rain - paj - Nov 2nd 2002
After viewing your site i decided to tackle the block paving of my drive. The drive is aprrox 41 sq mtrs 5 sq mtrs of it is a path that goes past my front window. The main drive is to take a van and a car so i thought it would be best to put a good sub base down, so i hired a digger and dug 1ft down (jesus those diggers are scarey! ) my idea is to put a base of 8inch,sand 1.5 inch and finally 2.5 inch (60mm) block paver. After digging down i found out i had a gas leak due to a rotten pipe so in came the gas man and repair was done.

This is when my dilema started. On the day the gas leak was repaired the heavens opened i had puddles everywhere, i mean large puddles! the ground where they dug out for the repair is very soggy and soft partly clay too. I dug most of it back out and filled it with dtp1 but it is still soggy.

What is not helping me is the weather, the ground is just a mess! water, mud and odd clay patches everywhere .What i need to know is will i be able to get my sub base down if there is a break in the weather? i spoke to a local landscape gardener and he said i should leave it until spring!! I have purchased some geo-textile to put down under the sub base but will it be ok to carry on even though the sub grade is wet and muddy and more rain is forecast? Apologies for the length of this but just wanted to explain as much as poss. look forward to your reply

forum answer Tony McCormack - 2nd November 2002
Your chum the local landscape gardener must be one of those soft sods that holes up for the winter just in case they catch a chill. The rest of us have families to feed and so we have to keep working to earn a living!

Today is a washout, admittedly, but, as soon as we get a dry break, clear off any sloppy, cacky mud from the sub-grade, cover the exposed sub-grade with your geo-membrane, and get a covering of decent sub-base material down, spread, levelled and compacted as quick as you can. Once your sub-base is in, that will help protect the ground.

If you have spare geo-membrane, put that down as a walkway cover, so that the crap isn't walked into the house - if you've no geo-membrane left over, get a few boards or decking sheets.

You can get your concrete bedded soldiers/kerbs in as soon as you get a chance, but leave the laying course sand and actual block laying until you know you've a couple of dry days when you can crack on and get most of, if not all, of the ground covered. And concentrate on covering the ground - don't be slowing yourself up doing cuts or fixing steps: get the laying course covered and then you can cut-in and do the fiddly bits as and when you get a chance.

It really isn't the best time to be laying a driveway or a patio, but it can be done and, look at it this way - when everyone else is spending next spring/summer digging and stoning-up and laying, you'll be sat out in the back garden with your feet up and a pint in your hand! smiley

Keep us updated as to your progress (or lack of it!)

2nd November 2002
Wow!i didnt expect a reply that quick (very impressed) i have noted what u have said the only thing that still worries me is the filling of the hole from the gas repair it is so soggy, when u stand on it you sink down a good few inches i did part fill it with dtp1 but not entirely. should i dig it all out again and just use dtp1 or do u think it will be ok, just dont want to get sub base down and then have probs with it.
Tony McCormack
3rd November 2002
The quick reply was just luck - I check the forum at least once a day, usually after me tea, but you were lucky in posting just an hour or so before I came along.

The soggy bit really does need to be solid before you start any paving work. Usually, the DTp will help firm it up, but, if it's still spongey, dig it out and backfill again using clean DTp in layers around 150mm thick, compacting each layer as you go. That should cure it. smiley

3rd November 2002
Managed to get about  two thirds of membrane and sub base down today (approx 2 to 3 inch) and wackered, is it ok that i didnt get all base down? i wackered the edge leading to unfinished part of base to create "feathered" edge, hoping to get rest done tomorrow afternoonish (back at work).

regarding the spongey areas i did put quiet a bit of dtp1 back in but as i said in my last message not totally. went over with wacker and there is movement in the spongey area do you think this may tighten up as the sub grade dries out? also in the odd part water as risen to the top after wackering but the ground does feel quiet firm to walk on. due to time of year i have started and the rain i will be happy if i can get sub base down and then wait for a good spell of dry weather giving any soft areas time to dry and base to settle ,what do u think?

the only spongey areas are where the gas board dug down to find the pipe, unfortunatley they didnt find it straight away so i i ended up with a line of about 4ft before the actual pipe. i am going on now so i will stop there.

Tony McCormack
3rd November 2002
I think you'll be fine. Make sure you get all the sub-base down as soon as you can and then let it stand for a day or so to see how it firms up.

There's a rumour doing the rounds that we're to have a couple of dry days towards the end of the week!

5th November 2002
Managed to get rest of sub base down today still not to required depth but have a good 3 to 4 inch down and all wackered, the spongey areas do seem to firming up alittle as more base goes down (keeping fingers crossed it will be ok) but are prepared to dig back out if needed.

the only thing thats puzzling me a little is setting the the finishing level and fall of the blocks. the drive is basically a square with a few sq mtrs of footpath leadinig past my front window which is rarley used. three of the sides are "fixed" one is a dividing wall between my neighbour, two is the concrete base into my garage and three is the pavement, this leaves an open side leading on to a small lawn. the pavement is the highest point which then falls towards my garage (approx fall is about 4 to 5 inch over a length of 6m) my thought was to use the line on the three "fixed" sides of my original concrete drive which did drain ok and then take the fall sideways toward the open side which is 5.40 m wide and onto the lawn.

I did look on the setting out page on this site but the more i read it the less i understood it (just didnt seem to sink in!) so the way i was going to do it was to peg at the highest point (the pavement) and run a line from that to the base of my garage which basically follows the old concrete drive. then from my garage door to the lawn side creating a fall about 2 to 3 inch and then back to the pavement on the opposite side of my starting point and then peg the middle to check accuracy right the way across width and length.What do you think? have i got everything totally wrong or is there an easier way(prob is). keeping me awake this bit.


p.s. if none of this makes sense it may be poss to get some photos taken which would prob. help.see what u think.

Tony McCormack
5th November 2002
Have I got this right??? - see sketch

paj layout seems to me that you are planning to dump all the surface water onto your lawn. Do you reckon it will be able to cope? Personally, I'd put in a gully or a linear drain in front of the garage base and then connect that to the SW system or a soakaway, as I never like to drain any area larger than 10m² onto a garden, unless it's exceptionally well-drained ground.

6th November 2002
Your plan was spot on and will put in linear drains just before garage and take it to sw system (the longest run! 9mtr) got a few prices today and cheapest i could find was £150 They came in 1mtr or 3mtr lengths - do you think that was a good price? prob go for the 3mtr lenghts, less joints.


Tony McCormack
6th November 2002
B&Q are doing a 1m length of Recyfix Linear Drain, complete with tinny grating, for a tenner. It's fine for residential driveways and is a much better price than you've been quoted.

It's a polyurethene channel, rather than a polymeric concrete, but once it's laid on a bed of concrete and haunched-in, it will be grand. We've used it on a couple of jobs lately and have been happy enough with the results.

8th November 2002
Weather permitting getting edges in this weekend,correct me if i am wrong but is it poss to use left over dtp1 and mix with cement to bed them in? and what ratio should i use. taking ages this drive, busy laying carpets at moment i wish drives were as easy
Tony McCormack
9th November 2002
Well, to be brutally honest, you shouldn't really use DTp1 as a coarse aggregate for concrete, but, for a residential driveway, it will be ok. The lumps are often a bit on the big side, and you will need to add some grit sand, probably, but it will do the job. On site, it would be considered a bit naughty.

I suggest 4 DTp 1 to 2 grit sand to 1 cement, and don't make it too wet - in fact, for bedding, don't add any water - there should be enough moisture in the aggs to initiate setting. You'll need to wet it up a bit for the haunching, though, but again, don't overdo it with the water. smiley

10th November 2002
Went to B&Q and got the linear drains do they just push together? only reason i ask is that i have noticed on some types there is a jointing piece to secure each section. was thinking of running some kind of sealent to get a good joint or do you think after bedding and haunching any leakage would be minimal.

You were right about using dtp1 for bedding mixture the lumps are a bit big, not quiet finished all the edges but i think i wil get some smaller agg. to finish the rest.


Tony McCormack
10th November 2002
They just link together with a sort of tongue and groove arrangement, I seem to recall. I know some linear drains have definite 'male' and 'female' ends, but some are more sort of unisex (or should that be hermaphroditic??)

Don't worry about getting a water-tight joint, though - the concrete bed and haunch will more or less seal them, and then, after a couple or three weeks, the silt/detritus will have filled any gaps the concrete missed.

12th November 2002
Booked time off work, so i have friday sat. sun and monday to finish edges give sub base final going over and get blocks down. just a couple of question to help me on my way, the wacker i am using hasnt got a rubber plate is it a bit risky using it on blocks? when i lay the main area should i set them slightly higher than the edges to allow for wacking and if so how much higher? fingers crossed the weather will be kind to me this weekend and i can finally get it done.


Tony McCormack
13th November 2002
Was it wise booking time off work? It's abso-bloody-lutely guaranteed to persist it down all weekend now! wink

Don't worry about the missing mat - it's not a problem with concrete pavers, other than the highly decorative types. For yer bog standard Driveline types or tumbled pavers, it makes no real difference.

Deciding just how 'high' to set the pavers depends on the bedding course. Some sands compact more than others., so, if I was to say to you leave them 5mm proud, you can be certain that would be either too much or too little. The only way to be certain is to do a test patch, but I appreciate this isn't always feasible on a one-off private driveway.

So, sticking my neck on the block, and assuming you are going to have a bedding course that's around 40-50mm thick, using a decent grit sand, then, assuming you go for the light compaction before screeding method, and you're using 50 or 60mm thick pavers, I'd risk saying you should leave them approximately 6-9mm high and this will compact down when you've done. Probably. Ish. smiley

If in doubt, err on the side of caution - it's much better to have them 3mm high than 3mm low, as high blocks don't pond and they may well settle that last few mmm over the next 6 months or so.

I'll be thinking of you, when it's lashing down, and the wind's a-howling, and I'm watching Football Focus in front of the fire with a steaming mug of Bovril on Saturday! smiley

19th November 2002
Did i get my drive finished?......did i hell!!!

friggin rain friday was ok got odd patch of subbase to correct level and wackered in checked all my edges then decided to leave linear drains untill saturday i do think it stopped raining all day but still manged to get dug out and set on base and mostly haunched in (was able to cover from rain) sunday just last length of drain to put in and connect to sw, when i exposed clay pipe i found it ran under my neighbours concrete path, the only bit i can get access to is the first joint in the pipe which is the opening which takes the grate and then goes down about a foot then curved at the bottom and then curves back up about a foot then curves onto a joint which is mortared.

I went to diy centres to find some plastic fittings to replace this but couldnt find anything practical considering the amount of pipework that i have exposed. i could really do with something that replaces the old pipe more or less exact but with an extra hole near the grate opening so a can tap in with my linear drains, any ideas where i could get such a pipe or any alternative?


p.s. how was the bovril and football

Tony McCormack
19th November 2002
That drain fitting sounds like a P-trap or something similar, possibly a grease interceptor. Can you get a piccie? Do you have a digital camera? If not, are any of the images in the drainage section of the site vaguely similar?

Whatever fittings you have, there will be a modern version that can be used to link your linear drain to the system, but it's hard to say just what from this distance. A piccie or even a sketch would be a great help.

The Bovril was a damned sight better than the footy. How we failed to score against Sgt. Wilko's bunch of journeymen defies explanation. And why Baros wasn't brought on is another mystery!

20th November 2002
looked at the drainage section and it does look like the p-trap, manged to get to a builders merchants today and came home with a t-section and adapter for clay to plastic i may be able to cut just before bend on the bottom, fit the adapter then t-section and a new grate on top. Looking at it though i will loose any fall from my linear to the t-section it could poss up rather than down. Do you think i may get away with this? i do have the fall over the 9mtr length of linear i have put in, maybe the overall fall of the water will compensate for the slight uphill at the t-section. Or should i shop around until i find something more suitable?


Tony McCormack
5th November 2002
How slight is slight? Are we talking 12mm? 25mm? 50mm?

You might be able to fettle the connections and get them to go in flat or with just a bit of fall, which would be the best solution, but, if it's a situation where you have no more than 25mm of backfall, you should be just about ok.

20th November 2002
Taken note of what the minimum backfall allowed, i was wondering if there is such a thing as a flexible pipe which would then go from my linear to the t-section instead of having to use "fixed" pipe and joints this would help a lot in gaining the fall required
Tony McCormack
21st November 2002
There's not, as such, but one "fix" that I have used occasionally when the use of conventional fittings is totally impossible because of lack of space, is to use 100mm diameter flexible land drain, but to lay it on a bed of concrete, and totally encase it in concrete, so that the pipe itself acts as a 'mould', and the concrete seals up the perforations in the pipe.

This is only suitable for relatively short lengths, certainly not more than a metre, and should not be employed in areas that will be subject to vehicular traffic. Do you think this might help your situation?

22nd November 2002
Managed to do the drain and i was hoping to start laying this weekend have been watching weather reports all week and things seemed hopeful for sat and sun. But now they say its going to rain sat afternoon and fine on sunday, my question is do you think it would be wise to start tomorrow and try to get as much down as i can before the rain and is it poss to work in between showers, should i get so many blocks down then brush sand in as i go along will this keep any rain getting to the bedding layer and then hopefully get the rest done sunday? not sure if i dont lay any blocks sat that i will get it all done sunday (approx 41sq mtrs) or do you think this is poss to lay in one day for an amatuer if get up at sparrows fart?.

One last thing ,should i wait until i have all blocks in before wacking or is it ok to wacker in stages? (just a few passes). You will probably gather from all the questions that i am eager to get it all done and dusted, i just cant see an end to it with the weather being as it is and only having weekends to do anything.


p.s. if you and some of your mates want to pop round and give an hand i will get the kettle on smiley

Tony McCormack
23rd November 2002
Get cracking today. Work between any showers, but don't be messing about brushing-in jointing sand or wackering until you've the whole pavement laid. You may need to make adjustments to the alignment before you piece-in the cuts, and sanding & wackering can bugger that up.

You should be able to lay all 41 m2 over the weekend, but cutting-in could take longer, depending on just how much there is to do, how complicated are the cuts and how competent you are at cutting them.

If you need to get the car onto the drive come Monday, then concentrate on cutting-in around the parking area, and get that sanded and wackered before you finish. You can piece-in the pedestrian areas later in the week, or even next weekend, if necessary.

I'd love to come and help, but I can hardly walk today, let alone lay blocks, so I'll have to pass on your generous offer. wink

29th November 2002
didnt get anything laid over weekend got called into work at last minute and didnt think it was wise to start sunday as i have to work this week end too not leaving me time to finish. Anyway, resigned myself to the fact that it will get done soon and not let my impatience get the better of me and end up making a cock up of it.

So all i have decided to do with any spare time is to keep going over the sub base with wacker which leads me to my question. An area of the sub base (approx 4sq mtrs) doesnt seem to be firming up when i use the wacker on it, all it does is sink into it leaving rutts. I know the ground under this didnt have much clay in it and i also put the membrane down, is it possible i have too much "dust" from the dtp 1 in this area? i was thinking of getting some bags of chippings and wackering them in hoping it will help firm things up a bit, what u think?


p.s neighbour across road had their drive done only took them one and half days, from taking concrete drive up to laying blocks, thought bloody hell! what am i messing about at!

Tony McCormack
29th November 2002
It's stamge that you've just one bit not forming up. Is it just loose/dry or is it squelching?

You've 4 weekends between now and xmas, and you can guarantee at least two of them will be crap weather, and one will involve some form of festive duty, such as shopping or visiting strange aunties, so that leaves you perhaps just one weekend to cover the ground in time for Santa. January and February are not months renowned for their kindness to paving contractors......the sooner you start; the sooner you'll be done. smiley

Sod what the neighbours have had done; I'll bet they've not had half the fun you have over the past few weeks! wink

30th November 2002
i wouldnt say its squelching, the day after wacking it does go firm and so do the rutts, its when i go over again with the wacker that it becomes soft and a slight skim of water apppears (there is no water pipes in that area). Its also the area where the rain settles as puddles due to the rutting, is the chippings thing not a good idea or not necessary?


p.s  oh what fun it is to do a drive on christmas daaaaay!!

Tony McCormack
2nd December 2002
It sounds as though the vibration from the plate is loosening the sub-base and the ground water. I've seen this happen loads of times and it does dissipate over time.

If you can get hold of limestone DTp1, that's usually a good fix for this problem, as it almost 'sets' once compacted in the wet. If not, leave if for a week and see if it's any better.

Your neighbours will really love you if you fire up the wacker plate on Xmas morning! wink

8th December 2002
Managed to get most of bricks down, i think i will get it all down today but i wont get any cuts done. will it be ok to leave cuts, sanding and wackering until next weekend? will any rain that we have cause any probs because its not finished? better crack on before it gets dark


Tony McCormack
5th November 2002
If there's no alternative, then you'll have to leave the cuts until next weekend. You might find there's been a bit of slippage and small areas near the free edges may need to be relaid, but the vast majority of the blocks you've laid should be ok, as long as you don't put that car on them, and you keep foot traffic away from those free edges.
8th December 2002
Manged to get all full blocks laid and at last it is starting to look like a drive! taken note of what you said about the free edges and not to put the car on, i packed the edges with sand where any foot traffic will be. Decided to try and do cuts during week even if its just an hour or so each night its better than nothing. I did the 45 deg herringbone pattern and even though the edges or not in i was suprised how firm the whole structure felt.


Tony McCormack
9th December 2002
That's the trouble with this time of year - the daylight drains so quickly after 3pm and it's a bugger of a job getting accurate marking and cutting done under artificial light.

The sand packing will hold the blocks sufficiently for foot traffic in the short term. It's a pity you can skive off work for a day - it's perfect cutting-in weather today. smiley

1st January 2003
Blocks are down and all cuts done, i know it should be done by now but last few weeks up to xmas were just mad so i thought i would leave sanding until i was off work.

Attempted to sand and wacker yesterday blocks were dry so i brushed all sand in and booted up the wacker, started off ok but then in some areas water came thru, so it all stopped there. Is it a case of letting it dry out and trying a small patch out after dry spell until no water comes thru? some areas were ok but i didnt wacker them fully thought it best to leave it all.


p.s. Happy New Year!!

Tony McCormack
2nd January 2003
Good to hear you're still worrking, paj. I thought you'd packed up for the winter!

With all the rain we've had recently, it comes as no surprise to hear that water is pumping up through the joints when you run the wacker plate over the blocks. You need to minimise this for two reasons...

1 - the water indicates that the bedding course is saturated and will become fluidised when vibrated which can cause movement or settlement of the paving from desired level

2 - the water brought up through the joints carries silts and muds and can cause long-term staining of the block surface if allowed to dry. If mucky water bubbles up, wash off the blocks with a watering can and fine rose using the minimum possible amount of clean water.

Try to give the blocks at least 48 hours after heavy rain before wackering to allow the bedding course time to drain. That'll be May, then! wink

All the best!

4th January 2003
Was thinking about trying to sand tomorrow afternoon (sunday) hasnt rained since receiving your last reply, the thing that worries me now is the low temperatures we are having just recently, is it ok to wacker if the ground may be a little firm?
Tony McCormack
5th January 2003
With the frost in the ground, you're not going to get proper compaction, but you might be able to get some sand into the joints.

The depth of frost has another effect: when it's only just 'crusting' the surface, then running the wacker over a paved surface won't do any harm, but, if there's a deep frost, the bedding layer can be solid, and rattling the blocks with a wacker plate can result in them chipping and spalling.

If I were you, I'd just brush in some sand and leave the wackering until we get a thaw.

I'n't winter fun? wink

Forum Question Pipes under paving - Mozza - Nov 3 2002
I've excavated the soil from the site where I am going to lay brickweave. In doing so I have exposed the top of a 4 inch bore plastic pipe used to take waste to the main sewer. The pipe disappears underground and I estimate has a max depth at this grade of 2 ftt. How do I go about protecting the pipe from damage during subsequent operations and do I have to take precautions for the buried section of the pipe?
forum answer Tony McCormack - Nov 3 2002
Your exposed pipe needs concreting-in. If it's uPVC, then it's way too shallow to be adequately protected. See the drainage section for info on concrete haunching for pipework.
Nov 10 2002
I've been thru hell this week excavating the soil around the plastic pipe but I've managed to concrete it and we are all pretty happy.

I've plonked in 16.4tonnes of hardcore and roughly spread it I've got to wack it and then level. Have you any tips on this -I have to be fit enough to get my pension on Thursday!

The next step is the surrounding soldiers but I am confused do I lay them in a lean 10:1 mix or a sand/gravel/cement mix?
Is there a rule of thumb that will tell me what quantity of dry ingredient I need to give a finished thickness with the finished mix?
Then to the sand layer. We are looking for a finished bed of about 50mm but the information sheets talk about allowing for compaction.I am not sure how much sand to oreder. The site is 76 sq. m and if I calculate for 50mm I need 6Te;60mm7.5Te;65mm8Te. If I am out with this figure I will have a tonne or so to get rid of somehow. And if I'm short I won't reach the soldier level. Any advise on this?

When it comes to the final wacking do I just wack away until everything is level or until the setts will go down no more?
I see everyone has already told -a great site you should publish the book.
Sorry for being so thick about things.

Regards mozza

Tony McCormack
Nov 10 2002
At least your job isn't flooded - lots of my email correspondents are complaining of being underwater this weekend!

Spreading the sub-base - use a rake to get it roughly level, then consolidate it with the wacker plate and check the level with taut string lines. You're looking for +/- 15mm It's worth spending a bit of time getting the sub-base right, as it has a major bearing on the long-term looks of the finished driveway.

Lay the soldiers on a lean mix concrete, roughly 6parts gravel to 3 parts sand to 1 part cement. There's a calculator on the Concretes page to help you work out just what you need, if you know the quantity of concrete required. You can work this out quite easily - multiply total length of soldier edging, by (width +100mm) by 100mm thickness. This gives the bedding, and for the haunching, it's length X 100mm X 50mm. If you have Excel on your computer, there's a spreadsheet you can download that works it all out for you.

For the laying course, the calculator I provide is set up to calculate the volume/tonnage of sand required to give a compacted thickness of approximately 50mm, so, you should need something like 7.5T - order 8T and any surplus can be used for knocking up concrete.

Wackering - you'll find that the blocks go down so far and no further. It usually takes 4-6 passes of the plate and then the damn thing starts bouncing around like billy-o. It's time to stop if that starts happening!  :)

I'd love to publish a book version of the site, but I can't get any publishers to make me a sensible offer. They either want me to pay for the privilege (and we're talking a 5 figure sum!!!) or they want to stick a certain so-called TV-celebrity's grinning fizzog on the front and pass it off as his work. Over my dead body!

Forum Question Brick Paved Low-load Footpath - wadj - Nov 28th 2002
G'day. Firstly, this site is amazing. It's very rare [for me] to find a site with so much useful information. Thanks heaps.

I would like to pave a low-load bearing foot path using old house bricks which have been laying around in the yard for quite some time. This way I can get two jobs done at once. The path is in the least frequently visited part of the house and is to lead up to a garden shed and therefore looks are not such a large issue.

What I was wondering is, for such a 'basic' path, do I really need to excavate to such large depths? The ground is very loose and sandy since we are close to the beach. Also, do I need a sub-base layer?

Thanks heaps,

forum answer Tony McCormack - Nov 28th 2002
I'm guessing, from your initial salutation, that you're not a native of these soggy islands, but hail from a land down under, where they have slightly different construction standards to those we use in Europe. However, the principals remain the same, wherever you happen to be, but to answer your points...

1 - Housebricks - we have severe reservations about using facing bricks (as we call them in Britain) for footpaths, as they can often crumble to mush in our damp climate. It may be different in your part of Terra Australis, or the bricks you have in mind may be eminently suitable, but it's worth checking with a local contractor/builder, if possible.

2 - construction - Large depths?? 200mm?? That's nothing, and it really is the minimum you should consider if you want the path to last more than a year or two. Given you've a reasonable sub-grade (the sand you mention) you could get away with just 75mm of a sub-base, but anything less just isn't competent. Then, you need at least 30mm of laying course sand, plus the thickness of your bricks, which may be 75mm or thereabouts, I'm not au fait with Australian bricks, but I assume they're not too dissimilar to the Boral bricks that are currently being imported to the UK, and they are 75mm (I think)

So, 75mm sub-base + 30mm laying course + 75mm brick = 180mm. If your sub-grade is as sandy as you inply, then such a dig is an absolute doddle: you shouldn't even break into a sweat!  ;)

Nov 28th 2002
Yep, I'm Australian alright.

Thanks for the info, here's what happened:
due to... family members... we just got straight into it and in short:
1. stuck bricks on some dirt
2. covered the bricks with dirt.

Since the bricks might crumble, and the bricks are all different sizes, there probably wouldn't be much point doing it properly anyway. Also, I don't think anyone wanted to pay for sand.

We didn't even bother levelling the path and we're hoping the rain will wash the dirt into the cracks (our brooms aren't very good).

I think we're a shame to this site. Sorry to make you write so much. At least I know to expect that the path will only last about 1 year (if we're lucky). sulky

Forum Question Price of Marshalls Paving? - Millers - Nov 29th 2002
I`m looking to block page my driveway with Tegula Driveset Traditional from Marshalls. The problem is, I cannot find a price for this. I would like to try to cost how much the project will cost me but without a costing for the major part (where would a block paving be without the blocks??) I`m struggling.

Would anyone know a rough cost per square metre?


forum answer Nigee - Nov 30th 2002
Expect to pay somewhere in the region of £18 - £22 per m² inc vat for Marshalls Tegula Drivesett. Trade prices will of course be less, but you can haggle with the Builder Merchants for a better deal. Of course the price depends on the quantity required, and the delevery address
Tony McCormack
2 December 2002
Is there much price diff for Tegula/Drivesett around the country? I've been quoted prices as low as 14.50 quid per m² (plus the dreaded VAT, of course) up to 26 quid per m², all for jobs of 100-250 m² in size.

I had to price some RMC Priory last week - Ber-luddy Hell! I wish I'd sat down with a stiff drink before they told me!! 26 quid per m², plus vat, plus delivery, and that's a trade price for a 450m² job just outside Manchester! Time for a chat with the architect, methinks!

Forum Question Drying wet blocks - suki - 29 Nov 2002
Well thought i'd drop in to see how the excellent site was getting along and just to say the constant rain is killing me, we have jobs from almost 3 weeks ago that we still cannot kiln due to the ground being constantly wet and except from getting the hair dryer out i am really stuck i cannot remember a time when it rains every day for weeks on end and even on days that it does not rain the ground stays damp and kilning is futile, any tips here m8y.
forum answer Nigee - 30 Nov 2002
I've been having the same problem - Sanding the joints in wet conditions. But I've got an answer.

I recently bought a 3 pronged blow torch - approx £50 and a large gas bottle - approx £30. Wait until there is no rain !!!! even if the ground is still wet. Blow torch the paving keeping around 6" above and in no time at all the blocks will be dry enough for sanding. A 40m² drive takes approx 20 mins to dry - depending on how wet. After brushing in sand and compacting, go over again with blow torch and give it one final sand - the heat will keep on drying the silica sand.  I've just managed to get 4 drives sanded yesterday - they have been waiting for 3 weeks. The best £80 I've spent in ages !!!  It means that I can get all my work done in one go and I dont have to keep returning to jobs and not making money - which is why we are all doing this for - certainly not for the love of it especially in our climate, although looking at a finished driveway still gives me a tingle even after all these years.

Contractor in Cumbria

30 Nov 2002
I actually had this idea the other day when i said to partner in jest that maybe we should use something along those lines however after thinking about it we thought better of it, but u say it works ??? so maybe we should rethink this one through and maybe try it out.

What make & model torch is it plz, and how do u get on with the sand after compaction do u not find all the water rising back up and clogging the kiln sand again when running the vib plate over it??

1 Dec 2002
Cant recall the make & model of gas torch ( I think it was Italian ). I bought mine from Hewden Hire Centres.

Yes some of the water rises to the surface after compaction - you have to dry the blocks again and give it a final sand. You are not guaranteed to completley fill all the joints but at least most of it will be done - What I do is leave a bag of Silica Sand with the customer at the end of the job and tell them to brush it in when the ground is completley dry.

You have to try something in this weather or you will never get any jobs finished.

1 Dec 2002
Well its sunday its 3:30 in the afternoon and im off to kiln sand a job why?? because its the first time the blocks have been dry in like weeks so i cant miss this up and seems as the job was quite big i was wackering in the dark, a great way to round off any weekend however the customer is quote 'over the moon' and the cheque is now in the bank and we picked up another job next door into the bargain which means im fully booked now till end of feb smiley

hayhow eh. i just wish it would go colder then it would stop raining so much. im gonna see if i can get one of them big blow torches tommorrow.

Tony McCormack
2 Dec 2002
Even with the blow torch, you're never going to get a fully sanded joint, as the lower reaches of the joint will still be damp, but you will be able to get sufficient sand into the joint to give adequate interlock for low-speed driveway traffic over the short term.

Even in summer, you have to top-up sand jointing 6 weeks or so after the event, and this is even more important during winter. If we get a freak dry spell between now and the end of Feb, it's worth darting around to all the jobs you've done since the autumn and top up the sand jointing while you can. One final check in March or April should then be enough to ensure full joints. It's a p.i.t.a, I know but it makes for good customer relations, and they tell their mates/families just how pleased they are with the attention to detail they're receiving. smiley

One caveat on the use of blow torches with any paving, but particularly with concrete blocks - don't dwell on one spot for too long. If you superheat a small area of damp paving, the water trapped within the block itself is turned to steam and will literally 'explode' in an attempt to escape, sending shards of concrete flying in all directions at high speed, and making a mess of the block in the process - keep that torch moving!

8 Dec 2002
Exploding water tony, u ever heard of water driven engine all u need to do is get the water to explode and drive the piston down and bingo u are a billionaire! smiley
Forum Question Steps and the dpc - suki - 03 Dec 2002
Whats your rule with steps and going above the dpc? were doing a job at the moment where were just under the dpc with the main body of paving but the customer really wants a built up step at the front door however that will lift us up level with the top of the dpc and just would like your advise.


forum answer Tony McCormack - 4 Dec 2002
This is becoming a very regular problem, particularly since the implementation of Document M of the Building Regs, and that's part of the reason why I've been working on a page to look at various 'solutions'.

The key issues are to minimise the risk of water or damp entering the building and to reduce or eliminate the chance of thermal bridging (heat loss).

The simplest solutions from a paving contractors point of view are to leave a 10mm gap between the step and thehouse wall, to use a preformed integral drainage threshold unit (such as 'ReadyStep') or to use a linear drainage channel. For what you're doing, I think the 10mm gap between your step and the actual building itself is the best option. The relevant documentation recommends this gap be at least 125mm deep, which takes you back down to, more or less, two courses below dpc, and it may be necessary to install some form of drainage at that level to deal with any surface water.

The new page I mentioned above won't be finished until the middle of next week at the earliest because of other committments, but I'll post a reminder to this thread as soon as it's available.

Forum Question Blocking on an awkward fall - deefa - 5 Dec 2002
Hi Tony
ive got a bit of an awkward job on at the moment, we are block paving a front driveway that slopes from the road down to the house at an angle of about 25 degrees, this in itself poses no problems as we have set down the fall from road to house accurately to within 2-3 mm the headache is that the drive also slopes away from left to right about three quarters of the way accross due to a difference in dpc,s between the garage and the house itself, in other words if you stood near the top left of the drive and placed a ball on the ground it would roll towards 2 o,clock. so we are dealing with 2 seperate falls! concerned about the screeding and making sure the joints on the blocks are even and tight where the difference in slopes are so pronounced?? is this just a case of sweetening the changes in the screed??

we have installed 2 pot drains to take care of water run off in the low spots but the slopes Tony the damn slopes !!

any advice for me on this one??

forum answer Tony McCormack - 6 Dec 2002
It's not uncommon to have to deal with non-orthogonal falls (falls not square or a parallel to the base line) but preparing the screeded bedding layer isn't all that difficult.

You have certain fixed points, such as the dpc level and the threshold level at the footpath/roadway, so these dictate what's possible. I find the quickest way of dealing with this scenario on a private driveway is to establish the soldier edgings/kerb, making sure they are aligned and profiled correctly and then to prepare the bedding layer by using these edges as a guide. Keep standing back from the screeded layer, and checking its profile, levelling or feathering as required to create an acceptable profile.

Only when you've 'sculpted' the bedding layer into a decent looking profile should you start the block laying. Unless there are severe changes in falls, it should be straightforward enough, covering the ground with all the full blocks and then cutting-in as required. However, if you do have sudden or pronounced changes in level, then keep checking the alignment of the blocks as you lay, to keep an eye on any pattern drift that may develop.

The key thing is, as ever, the preparation of the bedding layer. If you get that right, the blocks will follow, with the minimal of persuasion. An extra 10 minutes spent preparing the screed can save hours of frustration later.

6 Dec 2002
Hi Tony, thanx for the quick reply..i thought that would be the case but i thought id check if you had a more scientific way of going about it!!...i,ll make sure ive got my specs with me on monday when i start the bedding layer screeding!!!!...this has been one of those tricky jobs so far but after getting in the gulley drains and pot drains today it feels like weve turned the corner and should be finished to schedule by the end of next always we have taken before/during/after pics so i,ll send a piccy when done and you can see if i need to call in on the optician over christmas..eyes dont fail me now
Tony McCormack
8 Dec 2002
Watch out for frozen sand come Monday - the hard overnight frost that's expected will freeze a crust onto bedding sand, and you can't screed or lay blocks until all that frozen material is gone - either thawed out or scraped off and replaced with unfrozen sand.
Forum Question Burner for blocks - suki - 8 Dec 2002
hi tony

im looking to buy a 3 pronged gas burner the type they use for felt roofing. this would help out with such frost issues also hopefully drying blocks out so i can get some kiln down and get off a job. however finding a burner for the job is proving tough. can u recommend a make and model??

forum answer Tony McCormack - 9 Dec 2002
I've no idea what make/model ours is, and there's no way I'm going out there to clean off all the pitch and crap that's become encrusted upon it over the years, but I know we got it from Greenham Trading - or was it AG Strachan?
Anyway, you should be able to get one at a Contractors' Merchant or try a Roofing Merchant, as those burners are a popular item with the roof monkeys.
Forum Question Height of screed - Salewski - 5 Dec 2002
Once I have the base down and the edges are set, how much higher should the paviours be laid before a whacker plate is run over them?
forum answer Tony McCormack - 6 Dec 2002
If you read the page on Screeding you'll see that the amount of compaction is such a variable figure that's it's impossible for anyone to say that "the pavers need to be exactly so high above the finished paving level prior to compaction."

The reasons are...

  • the thickness of blocks varies between jobs
  • the thickness of the bedding layer varies
  • the 'compactibility' of the sand varies depending on type, source and moisture content
  • the degree of compaction is affected by the size/power of the vib plate
The only accurate way to determine the degree of compaction is by trial and error. Some typical values are given on the Screeding page, but they may not work for you. However, they are a good place to start and, after 20-odd years of 'trial and error' we find that these figures are usually "there or thereabouts".

Do a test patch to see what works on your project.

Forum Question When to compact? - ros - 18 Dec 2002
I am in the throws of extending an existing driveway and after as many tips as possible to the point of having conflicting ideas.

Sub base is down and compacted, soldiers set on croncrete all way round area and I understand from this site the best way is to screed sand layer proud, lay blocks then compact down to final height with a wacker, however today a local expert tells me the sand must be compacted to the final level before laying blocks or they will subside. Is this right?

Also am I wasting my time trying to complete this in the rain as weekends are the only time I have along with the hired wacker/cutter etc..

forum answer Tony McCormack - 19 Dec 2002
Hi Ros,

your local expert is wrong, I'm afraid. It is a requirement of all block paving that the blocks themselves are consolidated into the bedding. Part of the reason for this is to accommodate the slight variations in thickness that occur with all blocks. If the bedding layer is solid, with no give, then the blocks will remain higgledy-piggledy.

BS7533 Part 3 gives 3 possible ways of screeding in preparation for laying blocks, and the method we find to be most successful is that described on the screeding page of this site, namely, level sand out generously, lightly compact with 2-3 passes of plate, screed to level+6-9mm, lay blocks, then consolidate blocks down to final level. We find this method results in fewer incidents of settlement than any other.

There's nowt to stop you working in the rain, but heavy rain should be avoided, as it messes up the bedding layer. Also, you can't do the dry sand jointing in the rain - obviously. Light rain or drizzle is not normally a problem, unless it's in for the day, as we say, and then it does more damage to your spirits than it does to the actual paving!

20 Dec 2002
Thanks for that Tony.
Can you give any tips on how to best match the new drive into the existing. I have bought the same brand blocks as are already laid but they have been down for some years and there is an obvious difference in colour. Pressure washing has done little to return their colour and I don't really want to pick up too much of the existing drive if I can help.
Tony McCormack
20 Dec 2002
There's nothing you can really do to make the new blocks match the old stuff. Concrete mixes vary over the years; the dyes change, and the blocks become weathered, which just cannot be replicated under normal circumstances.

However, in 12-18 months, the new will have mellowed and, if you power wash the lot then, there should be less of a difference.

On projects where the new absolutely must blend in with the old, then the only viable solution is to lift some or all of the old and mix them in with the new before relaying. This gives a very mottled appearance at first, but it begins to blend in within a couple of months.

Forum Question Need a Contractor - ChrisDi - 3 Jan 2003

I am looking to have my driveway laid in block paving.

Its approx. 90 metres square. There are 75mm of chippings there now and around 8 " of hardcore underneath - I have dug down in a number of places and investigated. I want to use Marshalls Driveline 50 in Burnt Ochre with a Marigold Border. I have seen these colours in my local Builders merchant .

I recently had a rep knocking on the door from a firm near Carlisle. He quoted me £6,500 and then after 10 mins came down to £5,500. He said if I accepted now he would reduce to £5,000, but only if i gave him a non returnable deposit. I told him to **** off / go away !!!

Was I right in sending him packing?
I was thinking about paying approx. £3,500 - £4,000 to get the work done Is this about right?

I am in West Cumbria. Does anyone know of a reliable and trustworthy contractor who would be capable of undertaking this work?

Thanks for your help

forum answer Tony McCormack - 5 Jan 2003

you were right in sending the cold caller away. No-one should ever agree to work being carried out by an unknown firm, especially one with such negotiable prices and wanting an immediate decision.

For 90m² of that type of paving in Cumbria, expect a fair price to be somewhere around £4,500 +/- 300 quid. From what I've been told by local contractors, 50 quid per m² seems to be the going rate up there, for straightforward jobs. Obviously, you pay extra for kerbs, recess covers, drainage, etc.

To find a reputable contractor in your town/area, then, seeing as you're planning on using the Marshalls' blocks, give their Approved Contractor Service a call - 0870 120 7474.

Get at least 3 quotes, in writing, and make sure you see previous work done byy them.

Good luck!

6 Jan 2003
Thanks Tony

Over the weekend I've been given the name of a local contractor from a friend who had a drive laid last year. I phoned him and he E-Mailed me some addressess of previous work.

I went to look at some of his work and was quite impressed. Whilst looking a two of the jobs, the occupants came out and told me what a great service the contractor provided - very tidy, polite and efficient. They highly recomended him.

He is coming round tomorrow to have a look and give me a price. He cant do any work until the end of March as he is fully booked up.
He is not Marshalls Approved as I asked him. He told me that he doesnt believe in paying money every year just to be on a register - he prefers word of mouth and recomendations. He said he only takes on 1 job at a time and he finishes that job before starting any more as he doesnt believe in leaving jobs unfinished.
He wouldnt give me a price or a rough estimate over the phone - he needed to come and measure and look for himself.
Should I ask him any specific questions when he comes?

I would like the work done sooner rather than later, but as this contractor is busy for a few weeks I think I would rather wait and get a good job than get someone who can do it tomorrow and maybe regret it. Is this wise?

Thanks for your help

Tony McCormack
7 Jan 2003
There is no better recommendation than word of mouth, and I agree completely with your man - we neve join any of the so-called 'approved' contractor schemes, as the prime criterion for membership is the ability to pay the joining fee, and, as Groucho Marx said, I wouldn't join any club that would have me as a member! wink

The fact that this contractor insists on seeing the job before quoting is yet further evidence of his professionalism, so it's all looking good. When he does come to carry out the site survey, you need to ask about ...

  • construction method
  • drainage
  • guarantee - is it insurance backed?
  • time to complete
  • written quotation and/or contract
  • advice on colour scheme

...waiting until the end of March isn't a bad thing. The weather during Jan and Feb is unpredicatable and most contractors have a 4-6 week lead time all year round, so, if your man could start next Monday, I'd be more concerned as to why he's not gainfully employed!

Have a look at the Finding a Contractor page for more advice and remember you can come back here with any other questions you may have. smiley


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