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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Building Questions >> Concrete or Screed? https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1398195843 Message started by Lectrician on Apr 22^nd, 2014, 8:44pm

Title: Concrete or Screed?
Post by Lectrician on Apr 22^nd, 2014, 8:44pm

Looking to lay the floor in my lean to shed.

The floor is compacted soil with (at the moment) broken up rubble on top.

Was intending on blinding the rubble with chippings and sand, and then laying a DPM.

I guess then it has to be concreted, not just screeded?

Screed seems easier to lay than concrete, but I assume it has to go on a hard surface such as concrete, not just down onto the DPM?

Title: Re: Concrete or Screed?
Post by thescruff on Apr 22^nd, 2014, 9:00pm

Concrete then trowel or powerfloat it.

Title: Re: Concrete or Screed?
Post by TIMBA-WOLF on Apr 22^nd, 2014, 10:21pm

after the DPM, what thickness do you have left, and as for a power float, from my recollection, I do not believe you would have the room to swing a power float paddle set up..
also to get a good finish on a trowelled concrete (even a PF type) you would need a good concrete with a good "fat" content..

Title: Re: Concrete or Screed?
Post by woodsmith on Apr 23^rd, 2014, 8:03am

What do you intend to use the room for? If it's going to be lived in in any way I would add insulation under the floor first.

If you have soil under the rubble I would remove the rubble and dig the soil out, it's not a stable base on which to lay a floor.

If you are going to use rubble under the floor you need to make sure that you completely bind it with sand/stone otherwise the sand will settle into the voids and leave the concrete unsupported.

Screed does not have the same strength as concrete and it will crack if it is not supported by a good concrete base.

Once you get a mixer running, as long as it's not too big a room, it's pretty quick mixing it yourself.

Title: Re: Concrete or Screed?
Post by Lectrician on Apr 23^rd, 2014, 3:15pm

When I say soil, it is compacted soil which was under the existing path which has been dug up. It's sound ground.

The rubble is the old path, broken into small pieces.

It is just a shed for bikes, mower, tools etc. Insulation not really an issue, but would prefer a DPM.

I think I will get a builder mate to help lay concrete, as want the finish "good". Doesn't need to be perfect, but nice!

Normally have wood around the concrete to be able to pull a batten over or similar to level, but you cant do that "inside" a room as such?