Insulation board Kooltherm K12 and XTRATHERM 60mm

[platforminc]

Hi All.

I am reading my building control/architectural plan document, I am having a side/loft extension done, its a framed timber construction with EML and sand cement finish. For the wall insulation, a 60mm insulation board is required for the batterns/dry wall etc.

On the document it states that Kooltherm K12 60mm insulation should be used for the insulation element.

On the other hand, I checked Selco and they have a XTRATHERM 60mm insulation board, and its I would like to know that can I use this in place of the Kooltherm K12 board ?

Kooltherm: http://www.insulationshop.co/60mm_k...qZLOu2fqQ003tEl2Rmzyjt9YDThjXZfkaArteEALw_wcB
Xtratherm: https://www.selcobw.com/xtratherm-pitched-roof-insulation-2400-x-1200-x-60mm

This is the specification

Thanks in advance.

 

[freddiemercurystwin]

Yes they are like for like, the particular information you can check for comparison is their thermal conductivity, which as mentioned is near enough matching as makes no difference.

 

[tomfe]

An r value of 0.3 might make a difference if the wall just passes.
Though probally not, makes you wonder why k5 is speced though.

Why have you got a void between your 2 insulation layers?
That might cause problems would be better filling your joists then counter batten to add a service void.

 

[platforminc]

I'm not sure tbh.
Could it be something to do with allowing the setup to breathe ?

So are you saying I can go ahead with the
Other one and not the Kooltherm

What do you mean by if the wall passes ?

An r value of 0.3 might make a difference if the wall just passes.
Though probally not, makes you wonder why k5 is speced though.

Why have you got a void between your 2 insulation layers?
That might cause problems would be better filling your joists then counter batten to add a service void.

 

[tomfe]

What do you mean by if the wall passes ?

Who ever speced your wall will have worked out the u-value for that wall makeup. There is a difference (though slight) between pir and pur. If the BCO sees you using PIR and PUR has been speced you might get pulled up and asked to prove that this change will not effect the overall target values etc. Ask the person who did your building control drawings, they are really the only ones who can tell you if it's ok as they have all the information. That's the official answer....

However as the chances of BC even looking at the insulation is so small you could risk it and even if they do say anything tell them you are going to add an extra 20mm in the roof.

 

[tomfe]

Could it be something to do with allowing the setup to breathe ?

You have an unvented void between two insulated layers, this does really sound like a good place for condensation to form.
You'd be better off keeping the k12 flush with the internal side of the studs or fully filling the studs.

 

[tomfe]

deja vu