Gaps in celotex floor insulation

[Rich49]

Hello all

Thought this would be pretty obvious but came home from work yesterday to find the builder has laid the floor insulation in my new extension and seems to be large gaps everywhere…. I thought the joints were supposed to be butted up tight together… some of the gaps look 20mm wide along the whole length of the board in places…. Should he replace some of them? I wouldn’t imagine expanding foam for this many gaps was a good idea, and not comfortable having screed laid where there is these gaps, surely it would affect the structure over time?
Any advice welcome, pics attached
Thanks

 

[King Billy]

It's not acceptable. If the concrete gets under the insulation, despite the membrane, the insulation could well float up.
There's no excuse for it not butting up.
I wouldn't accept it.
If it's tongue and grooved, and that prevents butting up, it's been installed wrong.
It's just a matter of flipping some of the boards.

 

[freddiemercurystwin]

Agree it's not acceptable, also once he's redone it and you've seen it or seen photo evidence check the membrane is sealed where its joined else screed may seep through the gap.

 

[noseall]

Hello all

Thought this would be pretty obvious but came home from work yesterday to find the builder has laid the floor insulation in my new extension and seems to be large gaps everywhere…. I thought the joints were supposed to be butted up tight together… some of the gaps look 20mm wide along the whole length of the board in places…. Should he replace some of them? I wouldn’t imagine expanding foam for this many gaps was a good idea, and not comfortable having screed laid where there is these gaps, surely it would affect the structure over time?
Any advice welcome, pics attached
Thanks

Poor. 3/10.

 

[stevie888]

Poor. 3/10.

Genorous today!

 

[noseall]

Genorous today!

I gave him marks for DPM and secondary VCL. Although the latter served to hide the poor installation.

 

[Rich49]

Thanks for confirming my fears!!! Apparently the screed is going in tomorrow so guess I’ll just have to lock the doors until he agrees to fix it!!

 

[freddiemercurystwin]

You can print this off and shove it under his nose if gets funny. https://celotex.co.uk/assets/concrete-slab-floor_application-datasheet_nov18.pdf

 

[Rich49]

Thanks - I also ready about the perimeter upstand… that hasn’t been done either… is it a necessity ? Thanks

 

[freddiemercurystwin]

If you're doing a proper job, I would expect BC to pick him up on that too. Local BC or Private?

 

[Rich49]

Yeah it’s private

 

[noseall]

Thanks - I also ready about the perimeter upstand… that hasn’t been done either… is it a necessity ? Thanks

On external walls yes. The DPM should go vertically up the walls so that it protects the whole floor detail.

 

[Koolpc]

Blimey, that ain't good.

Insulation has to be laid butted up against each other. No gaps. Plus taped. I would contact him asap and tell him he can't move forward until that is all done as per regs....

 

[Rich49]

On external walls yes. The DPM should go vertically up the walls so that it protects the whole floor detail.

Oh yes the DPM upstand is done, I thought the celotex info sheet meant it needed a celotex upstand round the perimeter too !

 

[Rich49]

Is taping required if there is additional VCL on top of the celotex? If it is I’ll go get some tonight and do it myself. I have ended up moving all the boards myself to create one big gap in a corner and cut some smaller bits of celotex to fill the gap. Unfortunately none of the boards seem to have been cut straight so it’s still far from perfect. Wonder if I should get some expanding foam too cos I don’t think he is going to fix it