How to raise a concrete floor by 50mm?

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Hi,
I am building an extension and where the new floor meets the old there is a 50mm height difference. The new floor is Hardcore -->concrete slab-->100mm celotex-->75mm concrete subfloor.
i know i should have poured the subfloor to within a few mm and then used self levelling compound, but i didn't!

A bit of research suggests that a screed would be best, but i know that it won't be something i will be good at!
Would a simple concrete mix work? What is the advantage of a screed?
The floor will be covered in slate tiles once its all done.
Thanks for you help
James
 
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you are correct about a screed.like anything taking 1s time can produce a good job.
look on youtube for videos on how to lay a screed and see whether this is something you would want to attack.
 
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You could use ta level flex screed. Easy to use and can go up to 50mm.
Won't be cheap though.
 
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Hmm just googled that stuff, 40 bags @£18 a bag.... Not sure that's a goer!
I guess my question is, will a concrete mix work, even if it is not the preferred method?
I've also read something about grano mix, does any one have any experience with that?
Thanks
James
 
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ree

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OP,

Are you saying that you have poured two concrete slabs?

Do you have a membrane (DPM) in position?

Slurry the surface with sand and cement at 1:1 mix. Allow to dry.
Then slurry a workable area and allow to go tacky.
Hand mix a semi-dry S&C mix at 4:1.
Using the semi-dry sand & cement mix, lay your 50mm screed on the tacky area.

AAMOI: modern practice is to pour & finish the slab at the height required for the floor covering to meet the FFL - no screed.
 
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Hi,
I have one proper slab - 150mm w. steel mesh, then some sand blinding, then the DPM, then 100mm of celotex. I then should have poured the remaining 130mm upto FFL, but i didn't - don't ask me why! I am now 50mm short of FFL.

I suppose all i would like to know, is not whether a screed is best (i realise it is) but would a concrete mix work; are there any problems i would run into if i just mixed up some and poured it in?
 

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