Stone wall damp proofing

Hi Folks!

We recently damp proofed a farm house in Wales where the west facing walls had been allowing water penetration for many years despite the owners' varied and best efforts!

The house was originally slate tiled down that face but the many holes in the wall behind were a breeding ground for rats. Once the slates were removed the west elevation had a few windows blocked up (badly, unfortunately) and the walls were painted with an, allegedly, waterproof paint.

The problem with this house was three-fold: Firstly, there was a good deal of rising damp due to there being no DPC at all; Secondly, there was penetrating damp driven harder into the exposed wall by the weather and pressure created by being situated in a valley; Thirdly, there was excessive penetration around the blocked-up windows.

The walls of the property were at least 500mm thick with two outer skins of dressed stone infilled with rubble. As anyone in the damp proofing trade knows you can inject stone walls but only if it is properly coursed, a rubble centre creates a problem. So we decided to forego the usual inject and render method and use Oldroyd Plaster Membrane.

The old plaster still had to be removed because it was up to 75mm thick in places and the plastic plugs would not have been long enough to reach the stone! Once the plaster was removed we could see the water seepage around the blocked-up window and we knew we had made the right choice of materials. We removed sections of the suspended timber floor so that the membrane could pass straight through floor level and also protect the floor joists and boards by delivering any moisture much lower down into the floor void. Where the window had been blocked up, the stone work jutted 50mm out of the wall and there had always been a large lump in the wall that the owner had tried to disguise with decoration.

Due to the nature of Oldroyd Plaster Membrane, we were able to dot and dab on top of the membrane with plasterboard to bring them just proud of the window protrusion and then use a simple bonding coat to bring everything flush. Then it was just a matter of taping any joints and adding a skim coat of plaster to the now perfectly flat wall and refitting the skirting boards. Job done!

If you decide to use this method we recommend that you go more than 1m in height because although the rising damp may not get higher than 1m you may get a salt line showing on your plasterwork later on which will spoil the job; also in cases of penetrating damp it is possible to damp proof the entire elevation using this method. Be prepared for a lot of drilling, we used nearly 400 of the special fitting plugs in one living room wall alone and the plugs aren't cheap! However saying that, it does give peace of mind because it makes a job you can walk away from knowing that the damp will never come through there again!

Please view another type of membrane damp proofing project here: http://www.conifer-property-services.co.uk/damp_proofing_water_proofing.asp?ID=13&Level1ID=13&Level2ID=3

If you have a damp proofing or basement tanking problem please feel free to contact us on 01650 531 694 or alternatively visit our web site @ http://www.conifer-property-services.co.uk/. Our usual catchment area is Mid and North Wales, Shropshire and Cheshire but we do travel further for large projects. We would be pleased to hear from you.

See you all soon!