Upstand PIR and foam expansion strip?

[CH_18]

Hi everyone,

 

I'm in the middle of putting my floor down for underfloor heating. Typical set up, Block and beam floor, Radon barrier, 150mm celotex, 75mm screed.

 

I've put 25mm celotex around the perimeter upstands to eliminate thermal bridge, my question is, do I also need the foam expansion strip around the perimeter also? For reference it's a 75mm sand & cement screed with fibres.

 

Thanks

[Canski]

I would say not needed. 

[JohnMo]

3 minutes ago, Canski said:

I would say not needed. 

+1

[CH_18]

Thanks @JohnMo  @Canski

 

As I understand it (still learning), the 25mm upstand is there for thermal bridging and the foam strip is there for expansion of the slab? The longest length of slab is going to be 12m?

[Conor]

Our build was ICF so basically no upstand needed. The screed company insisted on the foam perimeter strip as said EPS wasn't compressible enough. I'd assume same applies to PIR.