Cavity by French door

[Hannah and her dogs]

I bought a 50 year old house that turns out to be a disaster! Today’s challenge is the floor by the French Window. I was lifting the grippers prior to painting the shirtings before fitting (having fitted!) Karndean stick down flooring.

It looks as if the house was built with a slate ‘bridge’ covered with about an inch of cement screed before the thermoplastic tiles were laid. When they fitted the UPVC French doors the slate was damaged. This didn’t deter my previous owners from just fitting carpet over a crumbling floor. As they walked on it over the years more damage has been done and I now have an open cavity full of rubble, and flooring fitters coming in 2 weeks.

Im thinking of clearing out as much rubble as possible, packing with polystyrene blocks and then topping them with a couple of inches Bostik Cementone which is advertised as waterproof. The flooring people would latex over that

Should I put a waterproof barrier between the cementone and bricks just to be safe? Is there a better solution anyone can suggest?

 

[Deleted member 267285]

Personally to get it right, I’d use a concrete mix, but happy to be corrected by a pro.

 

[Notch7]

hould I put a waterproof barrier between the cementone and bricks just to be safe? Is there a better solution anyone can suggest

Clean out debris

put in DPM so it sits in like a U shape and comes up the door threshold.

fill with concrete, cut DPM flush after