Dot n dab downstairs toilet

[doogle2009]

Hi, im just in the middle of renovating a house and currently DnD the downstairs toilet. The DPC is 2 course up inside, ive always been shown to board above this then often screed, floating floor or whatever decided are put down but as this is an old house all the floors are done and level through out so this would mean a step into the toilet if i put another floor down, can i board below this DPC??

thanks

Jamie

 

[Richard C]

Are the walls solid or cavity construction?
Curious why the DPC is 2 courses up the wall inside, is it a post installed system to combat damp?
Is the screed floor new?
Is there a DPM in the floor?
If so why hasn’t this been carried on up the wall above the DPC?

Something doesn’t seem quiet right to me!

 

[dextrous]

Is it in a cellar

 

[doogle2009]

sorry the damp proof is 1 course up but still quite a gap. i presume the floor is done from when the house was built - 60s or 70s. it goes rite threw to the kitchen where it luks like there is a membrane under the screed where i had to repair the floor. i presume its still the original dpc to. also which ever IDIOT rendered the outside put a drip tray on at appropriate height n then rendered below anyway so i spent a day chipping that off!

 

[Richard C]

My property is mid 60’s & uses a liquid membrane under the screed but you can see this rises up the walls (& the side of the screed), well above the wall DPC before being rendered. The floor DPM should always be at or above the level of the DPC in the wall; unless the floor membrane has been brought up the sides around the edge of the screed, the screed will always be in contact with a potentially damp section of the wall, leading to damp penetration both into the screed & the strip of wall below the DPC. You could try a liquid membrane on the strip of wall around the bottom, taking it one course above the DPC & even bond a strip of polythene membrane to that but I’ve no idea how successful that will be, certainly as far as using D&D boards or gypsum plaster is concerned; something still seems rather wrong to me.

 

[doogle2009]

any suggestions wot i can for for the gap? my plan was to use 3 inch skirting which wouldnt cover the gap, and i dont really want to screed the floor with a new membrane as it would then be on a different level to the rest of the downstairs.

thanks for the help