Damp Proof Course

I spoke to the builder towards the end of last week and he explained what they would be doing regarding the damp-proof course. As you can see from todays photo, the retaining wall has been extended upwards on it's inside edge to just below the floor level of the current house :

A horizontal DPC will then be installed all around, and this will link in with a vertical membrane that goes right down to the floor slab. Here it links with the membrane in the floor to make a continuous seal. He has opted to do this, rather then attempting to mirror the slope of the ground as it has less joints, and changes of direction - all of these are points of weakness that can eventually fail and let in the water.

The vertical membrane is a bituminous sheeting that is stuck to the walls. Prior to this, the wall is coated with a black resinous primer, which you can see has been partly done in the photo. You may remember from earlier in the year, there was a debate about how the membrane would be fitted around the wall ties. What has happened is that the builder has cut off the wall ties installed by the groundworks contractors and will replace them with a new set that screw into the wall after the damp proof membrane is stuck on. A sealer is applied to prevent damp penetration. All very hi-tech. I hope it works !

A slight concern I had was that using a horizontal DPC in the walls would leave it very high up the wall to the rear elevation (because of the sloping ground). I envisaged that a good proportion of the outer stone skin of the build would be below the DPC and would therefore weather differently. However, the builder tells me that the DPC in the outer skin will be stepped to match the contours of the ground so this is not a problem. How you deal with different DPC levels on either side of a cavity wall, I do not know, but I am sure they know what they are doing..........