Airtight layer location?

[DragsterDriver]

I’m going around in circles! I have 140mm frametherm in timber frame, with 50mm pir board on top, then battens and plasterboard.

 

one supplier is adamant that the intello can be stapled to the studs BETWEEN the frametherm and pir board. The other said over the pir board but it will be a painful job.

 

??‍♂️

[ProDave]

Why will it be painful?  Intello over the PIR and the service void battens hold it in place.

[DragsterDriver]

6 minutes ago, ProDave said:

Why will it be painful?  Intello over the PIR and the service void battens hold it in place.

Will staples hold it temporary while it’s battened?

 

on a side note- with pir and the joints taped- what does the expensive breathable intello do?

[MikeSharp01]

19 minutes ago, DragsterDriver said:

on a side note- with pir and the joints taped- what does the expensive breathable intello do?

Any vapour between the Intello and the PIR can come back into the building as Intello is designed to  be humidity variable so if its its damper on the PIR side than in the room the vapour comes back seasonally. Good info and video here: https://proclima.com/products/internal-sealing/intello/how-it-works#sub_navigation

 

[Chablais]

it will make sure you are air tight if you tape the joints and tape it to the ceiling air tight layer, ever fixed a puncture in a bike inner tube, the tiniest almost not visible hole and the tube deflates. So think how many of those size holes are in the PIR joints and gaps. Also prevents moisture laden air reaches cold parts of the wall construction and potentially condensating. It is fiddly but I would say well worth the time and effort if done neatly. Energy costs are only going to go one way, worth spending time and effort now to reduce long term costs.

 

[Thorfun]

1 hour ago, ProDave said:

Why will it be painful?  Intello over the PIR and the service void battens hold it in place.

this is exactly what I am planning to do this week! :-)

 

1 hour ago, DragsterDriver said:

Will staples hold it temporary while it’s battened?

I don't see why not. when I do it this week I'll report back and let you know.

[JohnMo]

Or use double sided tape to hold in place.

[Thorfun]

21 hours ago, DragsterDriver said:

Will staples hold it temporary while it’s battened?

so, the answer is yes, but not very well. the staples are very easy to pull out.

 

and so I will be doing @JohnMo said and purchasing https://www.toolstation.com/double-sided-tape/p44920. should keep it in place until the battens go on.

[DragsterDriver]

12 hours ago, Thorfun said:

so, the answer is yes, but not very well. the staples are very easy to pull out.

 

and so I will be doing @JohnMo said and purchasing https://www.toolstation.com/double-sided-tape/p44920. should keep it in place until the battens go on.

I forgot to say good luck, and take pictures!

I did have an ask around and most seem to staple on stud because a passiv cavity is huge and won’t have the pir layer.

[Thorfun]

1 hour ago, DragsterDriver said:

I forgot to say good luck, and take pictures!

I did have an ask around and most seem to staple on stud because a passiv cavity is huge and won’t have the pir layer.

yes I agree. and part of me is regretting not going for the twin stud passive wall build up. even though I'm saving a lot of money by installing the insulation myself it is a real ball ache and has issues, like this one, that need overcoming.

 

but I will persevere.

[PeterW]

14 hours ago, Thorfun said:

so, the answer is yes, but not very well. the staples are very easy to pull out.

What sort of staples ..?? And what length ..?? 
 

May be worth investing in an air stapler and some glue/resin coated staples as they won’t pull out as easy 

[Thorfun]

3 hours ago, PeterW said:

What sort of staples ..?? And what length ..?? 
 

May be worth investing in an air stapler and some glue/resin coated staples as they won’t pull out as easy 

8mm staples https://www.screwfix.com/p/easyfix-staples-zinc-plated-8-x-10-6mm-5000-pack/803cc

[PeterW]

8mm are too short and will just pull out as you are finding. 

[Thorfun]

10 minutes ago, PeterW said:

8mm are too short and will just pull out as you are finding. 

what size do you think wouldn't pull out?

 

I can buy more staples but I'm loathe to buy a new staple gun to take large staples if my current gun won't as this is just temporary until I get the service cavity battens fixed and double sided tape should do that job.

[PeterW]

Ok so switch to 30mm clout nails as they won’t pull out

[Thorfun]

1 minute ago, PeterW said:

Ok so switch to 30mm clout nails as they won’t pull out

never considered clout nails to attach a VCL to PIR! seems excessive for a temporary hold though. 

[PeterW]

PIR..??? Thought it Was timber sorry !!! Nothing will hold in that unless it is threaded 

[Thorfun]

13 minutes ago, PeterW said:

PIR..??? Thought it Was timber sorry !!! Nothing will hold in that unless it is threaded 

ha ha...no worries. I did wonder! 

[DragsterDriver]

Sounds like a multi person task!

[DragsterDriver]

Ok, I’ve still been unsettled about this and have spoken to intello. There’s a 1/3rd rule with insulation apparently- as I only have 50mm inside and 140mm between studs/rafters I can staple to the timber  

[Thorfun]

43 minutes ago, DragsterDriver said:

Ok, I’ve still been unsettled about this and have spoken to intello. There’s a 1/3rd rule with insulation apparently- as I only have 50mm inside and 140mm between studs/rafters I can staple to the timber  

so the PIR will be inside the VCL? yes, that's possible but me being a paranoid old git I'm concerned about off-gassing from the PIR in to the house. so I want to keep it all on the other side of the VCL so any off-gassing doesn't come in to the house.

 

obviously, this might not be a thing so don't let me stop you! 

[Thorfun]

@DragsterDriver I have started down the double-sided tape route and it is working well so far!

 

 

 

 

but I haven't tried to yank it off the wall yet (and I'm not going to!) but it is staying put for now and I'm sure it'll be ok until I can get the battens up to hold it all in place securely.

[DragsterDriver]

On 07/03/2022 at 11:56, Thorfun said:

@DragsterDriver I have started down the double-sided tape route and it is working well so far!

 

 

 

 

but I haven't tried to yank it off the wall yet (and I'm not going to!) but it is staying put for now and I'm sure it'll be ok until I can get the battens up to hold it all in place securely.

Looking good!

[Mr Punter]

On 07/03/2022 at 11:56, Thorfun said:

@DragsterDriver I have started down the double-sided tape route and it is working well so far!

 

 

 

 

but I haven't tried to yank it off the wall yet (and I'm not going to!) but it is staying put for now and I'm sure it'll be ok until I can get the battens up to hold it all in place securely.

 

Why did you use the intello plus?  You have foil faced PIR underneath.  I thought Intello was mostly for vapour permeable and / or blown in insulation.  Polythene would surely have been fine, or ali taped joins?

[Thorfun]

49 minutes ago, Mr Punter said:

 

Why did you use the intello plus?  You have foil faced PIR underneath.  I thought Intello was mostly for vapour permeable and / or blown in insulation.  Polythene would surely have been fine, or ali taped joins?

coz i'm a sucker for marketing. 😉

 

I wanted some kind of barrier to reduce off-gassing from the PIR in to the house and using polythene sheeting just didn't 'feel' right to me so I wanted something with technology that could potentially help in it. and after shopping around I found I could get the bee-knees stuff from Germany for cheaper than a cheaper AVCL so figured why the heck not!

 

I don't know if it'll make a difference but if I didn't use it I'd always be thinking 'I wonder if using Intello plus would've been better?'