Does Damp Proof Paint Work is a question we are often asked.
The questions we ask back are:
Do you know what the cause of the damp issue is, e.g. Condensation, Rising Damp, Penetrating damp, etc
What do you want to achieve
To be perfectly clear, if you have an issue such as rising damp, penetrating damp or bridging damp, then damp proof paint will not sole these problems.
What we do come across often on site survey visits is the use of a damp proof paint that has been rendered over, plastered over, dot and dabbed plasterboraded or cladded over very commonly, to get a property through a sale or, by a Landlord wanting a cheap and quick ‘fix’ and finally, builders taking on a specialists job thinking they know what they are doing and quite often, they don’t.
Damp proof paint is widely available in DIY hardware shops, big top retail merchants such as B&Q and Wickes, builders merchants and specialist distributors. It can be made in bitumen, latex polymer, acrylic, epoxy and polyurethane derivatives. What you most commonly find on the shelves of high street hardware stores and big top merchants are water based, bitumen liquid paints. There still are some spirit based damp proof paints but becoming less and less due to the advancement of othe types of paints that have less of an odour.
Some brands of paint have added fibres for crack reinforcement for external applications to flat roofs for instance.
The one key success for any brand or version of paint comes down to what we call; the bond, (key), to the host material it is being applied to. So, for instance, if you want to apply an external damp proof paint to the asphalt roof covering of your garden shep, or single storey flat roof extension, you will need to thoroughly clean down the existing asphalt. Remove any loose material. You will need to apply an appropriare Primer and allow to cure before applying a two coat application of a suitable external damp proof paint.
Put simply, if the material you are intending to apply damp proof paint to is not sound itself, the how can you expect the paint to work for any length of time? The bond of the newly applied damp proof paint will only be as good as the bond of the material you are applying it to.
Does damp proof paint work externally? Yes, but again, you need to ask yourself why you are applying it and what is the cause of the damp you are either trying to treat or protect against. If you do want to apply a damp proof paint externally you need to be sure you are buying a type and brand of paint that will have weatherproof qualities. It will need to handle extreme changes in temperatures. You will want it to stop rain water ingress and you will need it to be UV resistant against the suns rays.
All of that said, be mindful that applying paint to outside walls stops them from breathing. We advise that you seek expert advice before applying external paints that potentially, create an internal damp issue as a result of applying them.
When does damp proof paint work? We do not advise damp proof paint is applied to ‘mask’ an issue or is applied to ‘treat’ rising damp, penetrating damp or condensation. The three most common and correct applications of a damp proof paint are as a Cellar Paint below ground typically a small cellar coal store for storage use. A lot of pub Cellars have a white Cellar paint applied as the breweries do not want to spend a lot of money and the paint gets them buy.
Secondly, it is applied quite often as a liquid dpm to a concrete floor slab where possibly a plastic sheet dpm has failed or one has not been put down at all. For this use, we highly recommend the N-Virol Superseal liquid latex polymer as being perfect for this job. Thorough cleaning of the floor is required leaving no dust. It can be damp but not wet before applying two coats in opposite direction to each other.
The third most common application is as a barrier Primer coat to external walls of a new build basement before a geotextile cavity drain membrane is fixed to the walls.
Does Damp Proof Paint Work, in summary, yes, Damp Proof Paint does work and it works very well but preparation of the surface is vital and using the right version of damp proof paint for the right reason is also key to get the right results. Simply using damp proof paint to mask a damp issue or in treating other remedial damp issues, will always ultimately fail.
Alliance Remedial Supplies are PCA manufacturer members and qualified to advise on the right product for your job at hand. Call us on 01329 235252 for technical support.