Q. I’ve recently moved into a detached house with a reasonably sized cellar which I intend to convert into a useable living space. My problem is that the cellar has some damp coming through the brick floor and external brick walls, (to the point where the walls feel slightly clammy to the touch). I've done a lot of online research and it seems that a reasonable solution would be to "tank” the cellar floor and walls with an epoxy coating (as it seems a membrane and channel drain system would be too complex and expensive to fit and would seem slightly OTT for the small amount of damp). I've seen the product Cellarcote mentioned on the net, and it seems to be more suitable than other epoxy based waterproofing compounds due to it's high strength, but I'm not sure (as suggested in a previous question) whether it would be perfectly suited, or would any epoxy based waterproofers, as the cellar walls and floor are brick with mortar, not concrete. I have cleaned all loose materials from the walls and floor with a wire brush and I need some advice as to whether you think Cellarcote, or a similar product would perform better if I had the floor screeded and the walls plastered before applying them, or whether the epoxy would simply pull the screed /plaster up due to the hydrostatic pressure? Any advice you can give would be much appreciated!

Submitted by: LM
 

A. In over thirty four years we have never seen an epoxy coating system used in an old existing cellar for tanking that has remained successful. To the best of our knowledge there is no such system with third party accreditation for application in the situation you describe which must say something. Such a system is only as strong as the surface to which it is applied as would be a waterproof render. Furthermore your existing cellar has reached a 'status quo' level of dampness after many years and what ever was going to happen 'dampwise' has happened unless the water table changes for some reason. To apply an epoxy pore blocking system now would change all of this and who knows what may happen?

By far the most popular method used today to create a dry living space is Cavity Drainage Membrane. There are very many advantages and perhaps one of the most important is that it has little effect upon the 'status quo' level of dampness that the property has achieved in the cellar. There are the other advantages of no condensation problems, minimal preparation required, services may be concealed, it is a clean dry system, it is quick to install hence less expensive etc. You do not have to install perimeter drainage and a sump pump if you feel it is unnecessary but this would be a risk you would take - circumstances do change and you would kick yourself if a street water main burst and your cellar flooded because you did not design in drainage and a pump. Such circumstances would probably blow an epoxy system off the wall!

We would urge you to pursue a Cavity Drainage Membrane system.