This installation was observed and documented independently by pavingexpert.com from May to October of 2015.
The manifold benefits of using resin mortars to joint all sorts of pavements has been exhaustively covered on other pages in this series , but all the other products so far mentioned are intended for use with wide-ish joints, by which we mean joints wider than 6mm. However, as the range of materials used for paving has expanded exponentially over the years, so there has been a trend to using narrower and narrower joints, and once these joints drop below 6mm in width, the 'standard' resin mortars are not really suitable.
This is because the aggregate used is not really small enough to ensure that it can both enter the joint with ease and, more importantly, fill the joint completely without clogging which would result in voids within the jointing. Voids are a serious weakness within the joint and their presence makes it more likely that the jointing material will crack or fail and thereby threaten the structural integrity of the pavement.
Many of the more fashionable paving materials, such as sawn natural stone and, in particular, ceramic or porcelain paving , are manufactured with fairly exacting tolerances which enables them to be laid with what are referred to as close joints : joints that are in the range 2 – 5mm in width.
A fine mortar
To ensure a jointing material can enter the joint and fill it completely without clogging, a finer aggregate than usual is required, and to meet this new and growing demand, NCC Streetscape in conjunction with Germany's leading manufacturer GftK have used their extensive skill, flair and experience to produce a super-fine aggregate two-part resin mortar which is just about ideal for such applications. Somewhat less flair has been used in coming up with a catchy name for this product which struggles under the the burden of being known as VDW 815 Plus .
This new formulation has another advantage, as though being super-fine wasn't enough: it responds most favourably to being super-saturated with water during installation.
There is no such thing as too much water. It cannot be over-wetted.
In fact, the wetter the better. The paving to be jointed should be thoroughly soaked before putting out the mortar, and then more water can be used to help wash the mixed mortar into the empty joints. Finally, yet more water should be used to help wash off any surplus along with the residue once the joints are filled.
The use of plenty water has two major benefits when it comes to jointing pavements. Firstly, it ensures the resin-coated aggregates are thoroughly washed into the joints and compacted in-situ, with almost no chance of there being any partially filled joints or voids within the jointing.
Secondly, and most beneficial to porous stone pavings, by super-soaking the surface beforehand, the risk of the stone absorbing resin from the mortar is greatly reduced, and so the risk of the phenomenon known as picture framing, where a discolouration forms around the perimeter of each flagstone adjacent to the joints, is all but eliminated.
Installation Video:
The video below shows the basic installation technique. As with the other two-part rein mortars in the VDW range, the aggregate is pre-coated so only the bottle of hardener needs to be mixed in, and after approximately six minutes of thorough stirring, the now frothy mortar is emptied out onto the pre-wetted pavement surface and then guided into the empty joints using a brush or a squeegee, with more water being applied via a hose as required to keep the mortar moving.
Once the joints are filled and the mortar has had a few minutes to settle and lose its froth, more water and a soft brush are used to remove any surplus and to ensure any last bit of residue is removed.
Residential Application - Merseyside Patio
The mortar will harden over the next 24 hours and can be opened to careful foot traffic after this period. Pavements used by motors are best given 2-3 days to harden more fully before being opened to vehicles.
VDW 815 Plus is available in three popular shades – sand, stone-grey and the dark basalt. These are very similar to other resin mortars from GftK but it's worth noting that, with a finer aggregate being used, the finished joint is noticeably smoother, less gritty, than those filled with the standard VDW mortars.
Case Studies:
VDW815 Southport
Kandla Grey effect porcelain tiles just waiting to be jointed...
Remember to seal gap between tray and frame to prevent mortar flowing in and jamming the tray
The installer opts to apply NCC Porcelain Protector and Pre-Grout Treatment...
.... a liquid which is poured into roller trays...
...and then applied by long-handled roller to the whole surface
A sponge is used to remove any excess liquid
Time for the grout - VDW 815 in a handy 10kg pack
We start by adding all of the included bottle of hardener....
...then thoroughly mix in a safe area for around 4 minutes
After pre-wetting the paving, pour the well-mixed 815 direct from the bucket...
...and direct it into the empty joints using a rubber-bladed squeegee...
....lightly misting with water to help flowability
Once an area is jointed, time to rinse off with yet more water....
... and then sweep off any remaining mortar or water using a soft broom and leave the surface to dry
....but best to keep it traffic-free for the first 24 hours...
A few hours later, it's all looking great....
...and then it's ready to use and make the most of summer!
VDW815 Preston
Another porcelain patio - this time, around an outdoor pool in Preston (are they mad???) The tiles are being pre-wetted
Once again, they'll be using the convenient 10kg packs of VDW 815 - especially made for narrower joints
Put down some protection to protect the paving from accidental splashes and spills...
... add the whole of the bottle of hardener packed in with the mortar....
...and stir thoroughly with a powered paddle agitator for around 4 minutes.
Apply the thoroughly mixed 815 to a thoroughly pre-wetted patio area...
...and add a light misting of water to help it move across the surface and into the empty joints
Clean off as much excess mortar as possible, and rinse off with more clean water
Use a soft brush to sweep off any remaining grains of mortar and any excess water...
Allow it to dry for a day or so....
...and it's ready to be enjoyed - anyone fancy a quick dip?
Further Information:
Contact NCC Streetscape:
Tel: +44 (0) 1257 266 696
Other Product Studies featuring VDW mortars: