Building off a rc slab - Would you build this off this slab?

[Ted]

Here are some photos of the RC slab in the project I have taken on:











The plan is to lay 500 gauge polythene on this slab (a vapour barrier essentially) and then lay 62.5mm Kingspan. I then do a 90mm screed over the Kingspan and lay my floor finish on that.

However, there are many imperfections with this slab.

It is not level, nor smooth , nor flat.

The RIBA-qualified arch who has signed this work off says that the slab is fine for this method of construction but I do not see how you can accept inaccuracies in the slab if one is planning to lay a relatively stiff board on it and screed on top of that. You run the risk of creating cavities under the boards which could fail once the screed is laid.

I am a perfectionist when it come to concrete work and to me this is simply awful concrete work. But am I being too pernickerty here?

Could you let me know if you would consider building the above plan off this slab, or not?

Or would you pour a self levelling screed first before doing any more floor construction?

[lutonlagerlout]

I am a perfectionist when it come to concrete work and to me this is simply awful concrete work. But am I being too pernickerty here?

a bit,yes
i cannot understand why they didnt put the kingspan under the concrete==> normal procedure
as long as the screed has a minimum depth of 60 mm no problem if its thicker
you could always use some self leveling on the roughest areasjust to avoid voids??????
cheers LLL

[Ted]

I agree...

That is a much better method of construction IMHO; whacking it under the slab...