Does damp Proofing work

February 21, 2015
Damp Proofing - Choosing a
Plastic weathershield paint being peeled off a wall. Underneath the brickwork was sopping wet. It dried out once the paint was removed.

Plastic masonry paint being taken off a wall - you can see water running down the wall behind the paint - the building dried out once the paint was removed.

Removing masonry paint to allow an old wall to dry out. This client was unfortunately responsible for introducing me to Nick Price - at TwoClicks web development - and that's how this website came to be!

We are often asked about Damp Proof Paint. Does it work? The answer is very simply NO.

Damp proof paint traps moisture into a building structure. The more you put on, the wetter the structure underneath can become. Water can get into the building through the paint as a gas. When it cools down, and condenses to liquid water, it cannot get out because the damp proof paint traps it. It is a one way barrier really, allowing water in as a gas, but trapping it when it cools down. We frequently attend very wet, damp houses that are covered with many layers of damp proof paint. Every time, we peel the darn stuff off, and find the wall sopping wet underneath. As soon as the paint is taken off - the wall starts to dry out.

Don't ever be conned into spending money on damp proof paint. If you have a problem, or think you have a problem with a wall, research it and diagnose the problem properly - you will always find the real cure - and cause. And the solution will never involve damp proof paint - it may well involve limewash, if you want a coloured finish, but it must be properly breathable. Paint companies sell stuff that is 'micro porous' - dont be conned by that - it isn't, and does not breathe - it won't allow water to get out. The only true breathable paint is proper limewash.

Masonry paint is the same thing. We are often asked about Sandtex masonry paint. It does not work - it is not breathable, and traps water into the structure. I frequently come across Sandtex masonry paint in my building surveys - and every time we need to remove it to allow walls of the house to dry out.

If you want to paint the inside of a building, use the Earthborn clay paint range - they are breathable and inexpensive. Don't be conned into using 'breathabe' or 'washable' emulsaions - all modern paints contain plastics and are NOT breathable.

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