Sole plate can go where?

[meadowhog]

I'm putting down a floating screed (sand/cement) with ufh on 100mm insulation over concrete subfloor.(dpm under). I guess where the non load bearing stud wall sole plate is fitted is a matter of personal preference and was going to fit it on top where the expansion joints are.(70m split into 3 rooms). But what with the weather , timing etc I want to get the walls up first.

Is there a best place/way to fit the sole plate? Cut out the insulation and screw straight onto slab, or build up 100mm with bricks/blocks/etc and screw to that, or sandwich 50mm insulation between slab and sole plate or even gripfix it to the top of insulation, Or none of the above? I am presuming cold bridging is not an issue but the insulation may be an advantage.

 

[hotrod]

How thick is the screed going to be?

 

[meadowhog]

Hi Hotrod

60mm

Thanks

 

[noseall]

Fix it direct to the slab and pin a piece of dpm to the underside of the sole plate before fixing.

Also fix a run of horizontal noggins at what will be the finished skirting board height.

P.s. i am not a fan of inso' directly beneath the screed so we always fit it beneath the sub-slab.

 

[Chukka63]

dont forget to run rhe DPC/DPM up the stud wlla to lap your floor DPM

 

[meadowhog]

Thanks guys

I put the ins ontop of slab to have more efficient ufh reaction. However Im concerned the screed could crack due to flexing so I'm adding fibres and possibly SBR. Ive had a nightmare getting rid of the hollows and high spots on the slab. It may help someone reading this, I mixed sand in with self levelling compound to at least double its volume. It worked out a lot cheaper and set/dried quicker than a slurry. And yes I made up a weak sharp sand and 5:1 pva slurry for a deep hollow. That taught me not to rush the slab. Noseall, I agree with you if theres no ufh, put the ins under the slab.

 

[Chukka63]

i would have levelled the floor with sharp sand,increased the insulation thickness and had a chipboard floating floor myself.