Vapour barrier

[Onoff]

Does that wall pir continue down behind the horizontal timber? Ideally you want no gap / a continuation between floor pir and wall pir to avoid cold bridging.

[Pocster]

8 minutes ago, Onoff said:

Does that wall pir continue down behind the horizontal timber? Ideally you want no gap / a continuation between floor pir and wall pir to avoid cold bridging.

No 

 

Here’s a better photo 

[Pocster]

Horizontal timber is base of timber frame 

[Onoff]

25 minutes ago, pocster said:

Horizontal timber is base of timber frame 

 

Similar to what I did then.

 

I spaced all my timber off the wall by a minimum of a 5mm pack and gun foamed the gap behind as a token against cold bridging through the timber. I think your pir upstand wants to come up to the finished screed height. The upstand limits heat leeching through the slab edge as well as guarding against expansion when the slab heats up, to stop it pushing against the walls. Not sure if pir on its own is good for that. I used a corrugated cardboard/eps sandwich against the upstand. Others favour like a rubbery foam strip.

 

The cleverer brigade will be along shortly.

 

Edited April 9, 2019 by Onoff

[Pocster]

3 minutes ago, Onoff said:

 

Similar to what I did then.

 

I spaced all my timber off the wall by a minimum of a 5mm pack and gun foamed the gap behind as a token against cold bridging through the timber. I think your pir upstand wants to come up to the finished screed height.

 

The cleverer brigade will be along shortly.

 

So you are suggesting potentially this type of affair ?

[Pocster]

1 minute ago, pocster said:

So you are suggesting potentially this type of affair ?

Confused myself now . The original photo was upstand at finished screed - but that then means the edges won’t have any screed over them !!

Edited April 9, 2019 by pocster

[Pocster]

I can ignore the lip and do this ?

Can I trim the dpc under the timber frame as it gets in the way ?

 

 

[Onoff]

2 minutes ago, pocster said:

Confused myself now . The original photo was upstand at finished screed - but that then means the edges won’t have any screed over them !!

 

As it stands you've no insulation as I see it at the slab edge?

 

Think I'd bring one of those upstand pieces up to the screed height. What is it, 50mm? You could lose that pretty much with the plaster board and skirting and have the flooring just oversail the edge maybe...

[Pocster]

17 minutes ago, Onoff said:

 

As it stands you've no insulation as I see it at the slab edge?

 

Think I'd bring one of those upstand pieces up to the screed height. What is it, 50mm? You could lose that pretty much with the plaster board and skirting and have the flooring just oversail the edge maybe...

True - it would be lost with pb etc .

yeah upstand pir 50mm

So this type of thing ?

Dpc overhang pushing the back pir out hence why I want to know if just taking a Stanley knife to it and trimming flush to timber frame ok .

Edited April 9, 2019 by pocster

[Onoff]

6 minutes ago, pocster said:

True - it would be lost with pb etc .

So this type of thing ?

Dpc overhang pushing the back pir out hence why I want to know if just taking a Stanley knife to it and trimming flush to timber frame ok .

 

That's what I was thinking.

 

Tbh my dpm comes up and is glued to the face of the studs. The face of the studs is then covered in vcl and joined to the dpm that comes up. All to make it draught free as possible.

[Onoff]

I hereby give up the @onoffcrownfor makingitupasyougoalong to @pocster!

 

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[Pocster]

7 minutes ago, Onoff said:

I hereby give up the @onoffcrownfor makingitupasyougoalong to @pocster!

 

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You made it up good ! . I’m going with that !

Might have to pack between vertical timbers as membrane could sag between when screed goes on .

[Pocster]

26 minutes ago, Onoff said:

 

That's what I was thinking.

 

Tbh my dpm comes up and is glued to the face of the studs. The face of the studs is then covered in vcl and joined to the dpm that comes up. All to make it draught free as possible.

Surely I just need vcl 

Installer suggests 

 

https://www.permagard.co.uk/catalog/product/view/id/1532

 

Doesnt want black 

[Onoff]

8 minutes ago, pocster said:

Surely I just need vcl 

Installer suggests 

 

https://www.permagard.co.uk/catalog/product/view/id/1532

 

Doesnt want black 

 

Looks good to me. Thinking about it...On two previously damp walls (external path higher than dpc) I just ran a metre high piece of blue DPM a metre up the walls. I then put the stud wall in front of that. VCL (green) went on face of studs.

[Pocster]

1 hour ago, Onoff said:

 

Looks good to me. Thinking about it...On two previously damp walls (external path higher than dpc) I just ran a metre high piece of blue DPM a metre up the walls. I then put the stud wall in front of that. VCL (green) went on face of studs.

So should I bend the dpc timber up onto the studs and nail it ? (only about a 30mm overhang)

Then DPM 60cm wide around edges and up stud. Then that permagard membrane over the lot?

[Pocster]

Why can’t I just cover the whole thing in vcl and tape it further up the timber .

Why do the dpc strip around the perimeter?

Is the vcl thin and likely to tear ??? That why ???

[Onoff]

4 minutes ago, pocster said:

Why can’t I just cover the whole thing in vcl and tape it further up the timber .

Why do the dpc strip around the perimeter?

Is the vcl thin and likely to tear ??? That why ???

 

I only did the perimeter dpc as my walls were rough. Go with the vcl I would. 

[Pocster]

1 minute ago, Onoff said:

 

I only did the perimeter dpc as my walls were rough. Go with the vcl I would. 

I see !

Right ! Vcl over the lot and up past the upstands . All taped 

 

got it !

[Pocster]

Just now, pocster said:

I see !

Right ! Vcl over the lot and up past the upstands . All taped 

 

got it !

I *presume* I silver tape the joints on the floor between each pir piece ????

[Pocster]

If I put expansion tape at the perimeter like this 

 

https://underfloorparts.co.uk/product/underfloor-heating-perimeter-50m-foam-edging-strip-5rolls/

 

Does it go under vcl or ontop it ? ( i’m Guessing ontop ! )

[Pocster]

Ufh company said expansion perimeter not required ; pir upstands good enough for that . Nearly done one room of upstands - not neat - but every piece of pir is an off cut left over - so free ?

Mind you the 15 sheets of 150mm pir will be expensive ? 

Edited April 10, 2019 by pocster

[Pocster]

Pir upstands done .

Foam where I had to ; foil tape on joints . Osb on timber frame just so vcl has something easier to stick to .

[Pocster]

Done to @Onoff ‘s made up spec ! ?

[Pocster]

150mm pir ordered ; cheapest I could find certainly not local builders merchants .

Also found vcl ( looks the same as Permagard ) slightly cheaper . Double tape ( for vcl overlaps ) , tape for edges , foil tape all found cheaper on eBay 

[CC45]

I also put some of the foam on as well - its cheap & just an insurance policy.  25mm celotex as well.

 

19/12/15 I paid £37.89 for 8x4 x 150mm celotex sheets, I've still got 6 lurking in the garage how much are they now?  Have I made a profit by hoarding??