Where new extension slab meets stone building.

[Eddie Howarth]

Having an extension built on our 300 year old stone cottage. Slab has been laid as per current build regs but cottage is 650 mm random stone walls with no DPC (that we know of). Problem knowing what to do where slab meets stone wall. The previously outside wall will be an inner wall in the extension. Worried about damp rising up that wall. Has anybody any experience of this situation? Many thanks.

 

[Eddie Howarth]

Forgot to mention that in the photo the window will be the new doorway into the extension and the vertical DPM should be against the outer block and has since been corrected.

 

[chappers]

strictly speaking, normally you would lap that dpm into the existing. But as you don't have one, it's pointless. would have thought you would have seen damp already if you were going to get any