# Floor slab for extension



## Darlofan (Nov 24, 2010)

Planning just gone in for utility room, shower/downstairs loo, porch, replace garage and rear extension. Doing it mostly myself so will be in stages with utility room, porch loo first.
Wondering how you guys would lay the slab?

Watching youtube etc the way seems to be hardcore, sand, damp membrane, insulation, concrete then screed.


----------



## Kev.O (Dec 10, 2015)

I'm pretty sure we never used sand on top of the hardcore when we done ours, other than that seems spot on.


----------



## dholdi (Oct 1, 2008)

I put the insulation on top of the concrete because we have underfloor heating, apart from that the same.


----------



## dholdi (Oct 1, 2008)

The sand blinding is to stop the hardcore puncturing the dpm.


----------



## Kev.O (Dec 10, 2015)

dholdi said:


> The sand blinding is to stop the hardcore puncturing the dpm.


Good point, I was at work at the time and obviously didn't realise the sand missing from the pile on the drive.


----------



## Darlofan (Nov 24, 2010)

dholdi said:


> I put the insulation on top of the concrete because we have underfloor heating, apart from that the same.


No UFL in this part but will be in the rear and kitchen part.


----------



## Darlofan (Nov 24, 2010)

The screed bit worries me as we had that in conservatory of last house but it was never level so bugged me (I didn't do it). It was the 1st time I'd seen screed(sand/cement mix) used and up till then thought slabs were just concrete then tamped level and smooth.


----------



## wish wash (Aug 25, 2011)

Just make sure you follow building regs then you can't go wrong


----------

