Solid floor slab (extension) without final screed?

[oly]

Just wondering about feasibility of laying a concrete slab to domestic extension in one hit with no final screed? So, less excavation (a rougher final finish which might be okay if it's to be tiled). Anyone had experience of doing a floor like this?

100?mm C25 concrete (with mesh reinforcement if req'd)
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100mm Cellotex insualtion
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1200g DPM
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Sand blinding
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150?mm type 1 or hardcore

 

[r896neo]

Its perfectly doable. You do need to finish the floor well though so there are no large high spots or low spots.

Don't try it if its your first go at a concrete floor. Or get a plasterer to float it for you.

Also if your matching up to existing floors be very careful.

 

[noseall]

We leave room for a screed (regards extensions) for convenience because of the difficulties of achieving the correct levels and a scar free connection to the existing floor. You have the added problem of the thickness of the wall to make good once this has been removed, if you go via the full thickness concrete route.

Another reason is it is difficult to get a decent finish with concrete which can go south if it happens to rain. It will leave the surface dusty and friable.

UFH is also another good reason to leave room for a screed (and insulation).

Screeds can accommodate pipes or wires if needs be.

The screed can be shaped into the existing should the existing run out a little.

We never go for finished concrete. EVER.

 

[oly]

We leave room for a screed (regards extensions) for convenience because of the difficulties of achieving the correct levels and a scar free connection to the existing floor. You have the added problem of the thickness of the wall to make good once this has been removed, if you go via the full thickness concrete route.

Another reason is it is difficult to get a decent finish with concrete which can go south if it happens to rain. It will leave the surface dusty and friable.

UFH is also another good reason to leave room for a screed (and insulation).

Screeds can accommodate pipes or wires if needs be.

The screed can be shaped into the existing should the existing run out a little.

We never go for finished concrete. EVER.

Okay all good advice made me realise I should stick with conventional screed floor, obviously much safer.

 

[hankmarvin]

I'm planning to do it as Oly's first post but with wet ufh attached to the mesh.

Started looking into it to cut the cost on the screed and labour which is a fair amount over 35msq.


If you do the concrete floor right is there any other reason not to just have concrete instead of a screed?

I can measure off existing floor in three places to aid with getting the height right.

 

[oly]

Just to say the BC has said for 31 sq metres no need to add reinforcement mesh grid.

 

[hankmarvin]

yes that's what they said to me too but I need something to attach my ufh pipes to.