Steico flex 100mm WF compression tolerances

[sb1202]

Apologies if this is a daft question but I can't find an answer in any tech sheets or on here.

I'm looking to order 100mm steico flex 1190 x 375mm WF insulation and fit it into new stud walls. The stud walls are standard CLS at 38x89mm and will be built to 400 centres, so I'm presuming the 375mm insulation will give a nice tight fit and I can work out for the long side with dwangs.

My question is about the depth. Does this insulation compress into the depth of a 89mm stud against a membrane or do I need to pack out the joists with strips to get to the 100mm? (I couldn't get 95mm cls anywhere and 120mm/140mm deep studs are too deep for my application)  

 

Cheers

[Canski]

Years ago I made the mistake of putting 100 mm rock wool into a 4x2 stud wall. Bear in mind the 4x2 comes out at 97 x 47mm. We squeezed it in and fixed the plasterboard only for the fixings to pop. 

[Conor]

Are these external stud walls, and therefore is this your main insulation layer? Or, are these internal partition walls?

 

If the former, then you'll need to batten out using 22 or 25mm battens. If you compress the insulation, you reduce it's performance.

 

If these are internal partition walls, use 50mm acoustic insulation instead.

 

How are you running services?

[sb1202]

3 hours ago, Conor said:

Are these external stud walls, and therefore is this your main insulation layer?

Yes

 

3 hours ago, Conor said:

you'll need to batten out using 22 or 25mm battens

Not sure what you mean by this. Do you mean to pin a 25mm batten on to the short face of the stud? I can easily rip a 10mm strip for this.

 

3 hours ago, Conor said:

How are you running services?

Electrical only, through the insulation and sealed over the VCL with tape. This is a renovation so I can't afford reduce the room space with a service layer. 

[Russell griffiths]

I’ve only had this product in my hands for a few minutes, and it felt very firm. 
the stuff I messed with might not have been the flex version, have they made one more squishy for this sort of application. 
 

my opinion would be that it won’t compress down to 89mm. 
 

that’s a very expensive insulation option, have you looked at other methods. 

Edited yesterday at 08:03 by Russell griffiths