Damp ProofingIn the picture below we have a rising damp problem starting from the ground level and going up to the damp proof course or “DPC”. The damaged is caused by moisture in the wall that needs to escape or evaporate from the wall but is sealed in or trapped by paint, this is what causes the paint to delaminate and look terrible. The rising damp will usually stop at the DPC level because of a thick sheet of plastic built into the wall, this is specifically to stop damp rising above the floor level and getting into the home, this waterproof line is built on the floor level and is known as the DPC. Boundary or free standing walls are not built with a DPC because it makes them unstable, this is why boundary walls usually have rising damp problems. If you have rising damp inside your home or above DPC please contact our technical department for products used for injection.
When dealing with rising damp, there are two ways to go about repairing it, the “quick fix” solution or the permeant solution. Quick Fix The quick fix solution would be to scrape off as much of the peeling paint as possible back to plaster and apply 2 coats of Paintcors Damp Prime to those areas. Paintcors Damp Prime is fortified with white cement, which uses moisture in the wall to cure and creates a barrier against damp in the future. The first coat needs to be diluted with 10% turpentine to ensure maximum penetration into the plaster, this coat must then be left for 24 hours to dry. A second undiluted coat can then be applied, remember to only apply Damp Prime to areas scraped back to raw plaster, it will have no effect on a sealed or painted surface. The second coat must also be left for 24 hours before a top coat of your choice can be applied over it. NOTE: This method will not be a permanent fix and the damp will push paint off in other areas at a later stage, those areas can then be treated as before with Paintcors Damp Prime.
Permanent Solution This solution is usually met with a frown by the DIY’er because it involves chopping off all the plaster from DPC down to ground level around your home. It would be advised to call in a professional plasterer to re-plaster the wall. Once the plaster has been chopped off the wall back to brick, from DPC to ground, you can start to “Tank” the bricks. This is done sealing the bare brick with Paintcors Rhinoseal and allowing it to dry for 1 hour, then prime the bricks using a 1:1 mixture of Paintcors Acrylatex and cement. The mixing ratio is by volume and NOT weight, for example, fill a 1 litre container with Paintcors Acrylatex and empty it into a bucket, use the same 1 litre container and fill it with normal dry , good quality portland cement and mix it into the bucket with the Acrylatex.
Ensure the mixture is nice and smooth with no lumps to make a slurry. The slurry is then brushed onto the required surface ensuring that all the brush strokes end in the same direction, for example, vertical brush strokes as a first coat, and then, apply a second slurry coat at right angles to the first coat by using horizontal brush strokes. Allow half to one hour drying time between these two coats and allow 48 hours drying time after the second and final coat of slurry. This has now stopped moisture that is in the brick from getting into your plaster. The plaster does however still absorb moisture directly from the ground if it is down to ground level or slightly below ground. This can then be stopped by modifying your plaster mixture by substituting 60% of the water in your plaster with Paintcors Acrylatex, the same product used to make the slurry. You could alternatively seal your cured plaster with a silicone like Paintcors Klinkaseal, the plaster mixture MUST be a good quality 3:1 mixture. If the plaster is friable and of a poor quality, then the Klinkaseal will not work as intended. Below is a picture of KlinkaSeal that was applied to the bottom of the wall , and it can be seen that it is repelling the water .