Thermal bridging around window frame

[tvrulesme]

In the process of converting a garage to living accomodation. I'm replacing the old garage windows which were just about good enough for a shed with some high performance aluminium windows. 

The block walls will be insulated with insulated plasterboard mechanically fixed on to 25 x 47 battens.

 

For the window reveals, I was wondering if it's sensible to use some 25mm PIR around the blockwork joining to the insulated plasterboard insulation layer and install the frames on top (through the PIR into the blockwork) to minimise thermal bridging. 

Does this make sense?

[Mr Punter]

You may need building regs for this, and that could dictate insulation etc.  You may need to do the floor and ceiling.

[tvrulesme]

4 minutes ago, Mr Punter said:

You may need building regs for this, and that could dictate insulation etc.  You may need to do the floor and ceiling.

Yes it's all going through building regs and I have all my calculations for walls, floors and ceilings. Building control didn't specify for this reveal so trying to get a head start before giving him a call

[Redbeard]

10 hours ago, tvrulesme said:

For the window reveals, I was wondering if it's sensible to use some 25mm PIR around the blockwork joining to the insulated plasterboard insulation layer and install the frames on top (through the PIR into the blockwork) to minimise thermal bridging. 

Does this make sense?

 

It does but how would you detail the 'raw' PIR perimeter on the outside - just a timber (or Alu?) fillet?

Edited Wednesday at 19:58 by Redbeard
Remove extraneous'n'

[tvrulesme]

5 minutes ago, Redbeard said:

 

It does but how would you detail the 'raw' PIR perimeter on the outside - just a timber (or Alu?) fillet?

Outside is rendered so I was thinking of filling with render carrier board and render over it

[Nick Laslett]

Good discussion here about cold bridging, includes discussion of window reveals. 
 

 

 

Edited Thursday at 07:52 by Nick Laslett