Building over Damp Proof Course (DPC) ? Protecting wall with Membrane ?

[steve_boat]

Someone mentioned to me that you could build above the external Damp Proof Course (DPC) as long as you protected it with a membrane Damp Proof Membrane (DPM).

Im not convinced and think this will cause issues long term and wanted some other peoples thoughts on the matter ?

Please see below, existing and proposed sketches explaining the detail in more depth.

My initial concerns are as follows :

- a) If any moisture gets between the DPM and the brickwork above the DPC it not be able to escape and will cause issues
- b) If any moisture / rising damp gets introduced into the brick work below the DPC it will not be able to escape and will cause issues
- c) The bond between the DPM and the brickwork could be prone to failure
- d) If any water gets behind the DPM during a freeze it could expand and open cracks which could let more water / moisture in
- e) Im not sure but the detail may be in breach of building regs (would be keen to hear what reg if any is breached)

Im keen to hear other peoples thoughts on the matter and wether this is a good construction detail or not. Im skeptical that it is.

 

[^woody^]

Not OK

Is it a solid wall?

 

[steve_boat]

Not OK

Is it a solid wall?

Thanks.

Im not sure if its solid wall or not, but there are not any weep holes.

There are penetrations just above and below the DPC for waste water pipes and vents to rooms etc (although not a sub floor vent or weep hole)

Would be keen to hear your reasoning as to why its not ok.

 

[^woody^]