Engineered wood floor over PIR upstand (thermal bridging and strength)

[paro]

Hi All - Trying to figure out the best way to deal with the thermal bridge insulation around the bifold doors. Originally I was going to pull the 25mm PIR upstand around the whole floor including the bi-folds but the more I think about it the less I think it's the right way to go. For the rest of the room it will be lost behind the plasterboard and skirting but for the bifolds the floor will run all the way up to the edge and because its a herringbone pattern floor I am not sure about sticking down onto PIR and whether there is a risk of compression over time. 

 

Would appreciate any views on how best to approach this. I've sketched out the way I thought I was going to do this originally against alternatively just allowing the foam strip to go up to the bifolds.  My preference now would be option 2 but not sure if I am going to give myself issues with thermal bridging

 

Thanks, Paul

 

[JohnMo]

You could live with the foam strip as your door frame will be an insulator anyway, in effect no thermal bridge.

 

But is your drawing correct, the frame looks to be below floor level, if you want it all level wouldn't you get a level threshold frame? Would you door actually open and close correctly as drawn?

[paro]

Thanks. So a flush threshold from the inside is the goal. The bifolds open outward and don't impede on the internal space at all so think I can bring the floor all the way to the edge of the frame. I was told that what I have is appropriate for a flush threshold. The drawing extract from for the door comes from the manufacturer so hopefully I'm good on that front. 

[Conor]

Keep the upstand. The wood will be fine. I've 7mm laminate over a 50mm upstand and it's fine. I put a bead of silicone between the foam and boards, rather than underlay (as per the laminate instructions).

[Nickfromwales]

If that worried just use 2 runs of Compacfoam (20mm) to give 40mm of thermal upstand, instead of the PIR, as that's rock solid and can be bonded without any risk of future movement.

[paro]

Perfect, that is exactly what I need didn't realise I wanted, albeit not cheap. 

[Nickfromwales]

1 minute ago, paro said:

Perfect, that is exactly what I need didn't realise I wanted, albeit not cheap. 

21^o (formerly the Green Build Store) stock it in strip form.

[paro]

So it has just occured to me that I may be about to make a terribly expensive mistake.

 

For an engineered wooden floor it is recommended to have a min 15mm expansion gap around the whole floor. Personally I don't really understand that in the context of a floor that is glued down as surely it can't really more in any meanigful way without pulling itself up. That said if I want a flush threshold up to the back of the bifolds I can't leave a gap and I'm not aware of any flexible material that looks like wood that I can install around the edges to allow for this. 

 

Is this a problem that means I need to switch to tiles or is there a clever solution that I'm not thinking of?

 

Good job I'm always thinking ahead  Ordered the screed today as well.

 

[paro]

Okay so it sounds like liquid cork or regular cork is the solution here. Panic over!