problem where extension meets orginal wall

[forward]

I posted a query on tiling. Posted here as I think its now a building issue. From a request for photo lifted lino (on part of the floor) and noticed a bit damp or condensation (seemingly went quickly since lifting lino) . We had extension circa 18 months ago last year and all seemed fine). The new ext floor has membrane and insulation whilst the original floor is concrete with no membrane or insulation. The problem is where the old external wall was . Its a skim over original DPC. Can I just put some waterproofer over the section or do I need to dig out say a brick deep, put DPC membrane down and up sides and then concrete over?

 

[^woody^]

If it is a skim over the original DPC, then presumably its not damp but condensation.

 

[forward]

Thanks. If we choose to tile do we need a waterproofer etc underneath? Or will the tiles themselves deal with condensation?

 

[^woody^]

You wont get condensation issues on top of tiles nor underneath