slump for floor screed?

[CharlieB1981]

relaying the kitchen floor, hardcore and DPC is down, just not sure what 'slump' to order for the readymix for the main slab

area is 3x3mm and laying it about 120mm deep, this will have 75mm insulation and underfloor heating in 65mm screed after.

structural engineers recommended reinforcing the main slab with wire mesh.

whats best, very dry mix, lay 50mm lay the wire then lay the rest on top, or prop the wire on blocks so it'll sit in the middle of the screed and request a wetter mix.

many thanks in advance.

 

[Blagard]

structural engineers recommended reinforcing the main slab with wire mesh.

Really? So let him specify the type and where in the slab to put it. Use spacers to position. It is not as if it's bar reinforcement where you would blind the surface to work from it. Seems OTT to me

Click for slump guide

 

[noseall]

area is 3x3mm and laying it about 120mm deep, this will have 75mm insulation and underfloor heating in 65mm screed after.

structural engineers recommended reinforcing the main slab with wire mesh.

For the sake of a couple of tonne of gear we would mix this ourselves affording us time to faff about with the mesh.

I would personally go for a thinner slab (100mm) and have a thicker screed.

Having reinforcing in such a small thick slab seems a bit much to me. Is the ground beneath unstable?

As for slump, you are fretting and reading too much into it.

If you do happen to have readymix just make sure that the gear is workable. Lay a couple of inches down, drop the mesh on then lay the rest.

 

[RonnyRaygun]

If you've got a decent layer of hardcore and good ground below that, you won't have any problems with the concrete. The mesh would be there to prevent shrinkage cracking, but as long as the concrete doesn't dry too quickly, mass concrete of that size on a DPM should not crack anyway.

 

[CharlieB1981]

Cheers everyone.

Wire mesh was recommended as the house had subsidence in the past and although there's been no movement recently it was recommended as a precaution.

Only confused over the slump rating as I've not done a floor this big before and the ready mix company insisted I tell them the slump rating before ordering!

As for thickness, I have a desperate ugh contractor who recommended no thicker than 70mm for the top screed, so would need to increase the main slab so it's the right hight