Does damp proof paint work?

We are often asked about Damp Proof Paint.  Does it work? The answer is very simply NO.  These paints are also sold as Cellar Paint, or Masonry Paint. 

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. The same can be said for Weathershield paint - it traps moisture and has to be removed. There's another product called Stormdry that we have seen causing major problems.  All these products are sold on the basis they 'protect' your wall.  They do the opposite.

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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