damp internal wall

[sarahproperty]

i have a damp patch on the corner wall to my house where the house meets the drive/garden. the driveway is higher than the house at this corner and that is why i told the driveway man not to butt the drive up against the house. instead there is a gap with pebbles in it. where the garden meets, there is a step down from the drive level to the garden level and again i have made sure the step doesn't butt right up against the wall as i know that this would breach any damp proof course.

however, i don't actually think there is a damp proof course at all. the corner i am talking about used to house an outside toilet and i don't think the builders when they knocked it through added any protection to the flooring/walls there.

i don't think there is any more i can do from outside as the driveway cant be lowered, but my dad mentioned that he thinks there might be some kind of chemical that you can maybe drill a hole in the wall from the outside and then squirt the chemical into that.

the damage so far is just the wall above the skirting is damp so that the paint has bubbled and come off. its less than a foot high and doesn't seem to be getting any higher.

any advice is greatly appreciated.

 

[JerryM]

it's not a good idea to have anything against a wall that is approaching the height of the "dpc". this "dpc" may or may not be immediately visible but does exist and needs to be at least 2 brick courses down from the internal floor level. some dpc's are visible ie plastic dpc or slate or engineering brick

the drilling that you refer to is a chemical dpc (a liquid or cream injected into the wall). this only produces a dpc at the brick course which is injected.

if water contacts the wall above any dpc then it can pass through the outer leaf of the brickwork. this is normally ok if the house has a cavity. however cavities are known to often have debris in them particularly at ground level. this allows the water to bridge the cavity and pass into the inner leaf and then the plaster.

i don't believe any form of injection would be of help.

if you can't do as you say "anymore outside" then i feel the only answer would be to tank the inner wall. this would involve taking the plaster off to 1.5m, applying a chemical painted on membrane, rendering and replastering.

this is quite a disruption and cost. my way of thinking is always to try to cure the problem outside if possible (usually cheaper).

Perhaps a photo might help to get thoughts from a few on the forum.