New extension solid concrete floor tie into house with raised wooden floor.

[eeldranrab]

I am planning on probject managing a rear extention next year and I have most things sussed except how to tie in and ensure continuous damp proofing between new concrete floor of the new extension and the existing house floor which is raised wooden flooring. Can anyone help on this.

 

[tomfe]

Your suspended floor wont have a dpm. You will have to run ventilation for the void however.

 

[vinn]

Why not scan a section view of the proposed extension floor?

 

[eeldranrab]

Having issues with scanning so will try to explain my plan. I am ok with continuing the ventilation under the new floor and understand that the raised floor not have a dpm layer but dpc in the brickwork to form a block of the damp. My new outer wall construction would be cavity wall with the dpm over laying the dpc on the inner wall and an independent dpc along the outer wall.

My thoughts on the connection to the existing house is to build a new inner wall with dpc overlapped by the dpm from the slab.

Break out the existing house wall inner and outer layers down to as far as they need to go to fit some small length joists spanning the gap between the new built wall and the existing joists. If needed adding new dpc on the what remains of the inner and outer walls of the existing house thus blocking rising damp.

Does this make sense and sound plausible?