Screeding over a uneven stone floor!

[boza]

Hi
I need to screed over a sloping stone floor probably about 8 metres in area and screed from about 3 inch depth and taper to nothing.The stone is too big and thick to move so need to level with screed. Will i be ok to use a grit sand and cement screed with a cement slurry/pva mix laid down before hand, if so whats the best ratio and if i cannot screed to nothing with sand/cement am i best stopping with an inch depth to go and use a self leveling mix, hope this makes sense, any advice would be grateful!

 

[malc]

NO cement and pva slurry this will dry out before the screed and the screed will fail.

apply sbr to oversite, add sbr to the screed mix. you can screed this down very thin.

 

[Dr.B]

Is there a DPM?

 

[boza]

There's no DPM it's the original floor probably being down 100 years plus no sign of damp dry as a bone. Was going to put down a liquid DPM but think I'll be wasting money.Has anyone used grano 6mm to dust been told mix this with grit sand and cement at a ratio of 3:3:1!

 

[malc]

have not laid a grano screed for years, did not know grano dust was still available as it is classified as cancergenic.

 

[bubbles65]

Any more info on that @malc? We have grano up here, i use it all the time in my wet dash mixes and it's brilliant for screeds :RpS_thumbup:

 

[Dr.B]

I'd put a liquid DPM before screeding.
Then do as @malc said.

 

[boza]

I've decided to lift the stones with a big bar and level using grit sand done half a dozen easier than I thought! Thanks for the advice guys.

 

[Dr.B]

If you lift the stone out and lay a new floor you might make a few quid on the stone.
I've done it a few times with skate floors or quarry tile floors.

 

[boza]

I did think that originally but it's extra time and effort, some of these stone flags are mega heavy.