Insulated Board for Window Reveals

Technophobe

Hi

Anyone any ideas on what the minimum depth Insulated board you can get for Window reveals? And who supplies it or where it can be got? (example, it looks like Xtratherm do a 9.5mm + 17mm as their minimum)

I dont want to cover up too much of the window frame but I do want to insulate well, so any ideas welcome. The windows will have the usual fitting and foam from the installer's point of view and I will also be taping them with tape from Moy....so what are my options in terms of keeping below 30mm or so??



thanks

Technophobe

So far, have found Xtratherm will provide Polyiso at 27mm (9.5mm board +) and also a Polysterene 22mm (9.5mm board +)...

In case it helps anyone....If anyone has other suggestions let me know...

thks

mickdw

You inner blockwork should have been kept back 20 to 30mm compared to the outer blockwork. THen fit a treated timber batten a position of window frame so that window is actually smaller than the internal block opening thereby leaving lots of room for insulation.

clint_eastman

Q?

Is it best practice to extend the insulated slab around the reveal? Has it always been like that? The reason I ask is that I haven't seen it done in the last few houses some friends have built and hadn't planned on doing myself because I didn't think it was done or the "norm".
I can see the logic in it, but thought it overkill and the losing of alot of the window frame didn't appeal to me. I'd glady take some advice on whether or not to do it.
Kingspans data sheet say that it should be done to avoid cold bridging but don't say in what manner or give a technical detail.

clogher71

Hi

I am in the same position now, did not leave enough room for insulation, I cannot find anything below 25mm.
Very intrested if you come up with anything.
I think I might have to foresake insulation around windows.....

Technophobe

Well, as I say above, there is the 22mm Polysterene option, not as good as Polyiso but better than nothing...

HTH

bakerbhoy

My window supplier fitted 50mm extension pieces to the frame edges .I then insulated outside reveal with phenolic board before plastering and used 50mm thermal liner boards on the internal reveal over airtightness tape having closed the reveal with 30mm xtratherm and siliconed damp coarse to outer frame.

soldsold

"My window supplier fitted 50mm extension pieces to the frame edges .I then insulated outside reveal with phenolic board before plastering and used 50mm thermal liner boards on the internal reveal over airtightness tape having closed the reveal with 30mm xtratherm and siliconed damp coarse to outer frame"

Thanks for the info but can you clarity the different stages? Its a bit vague/ complex for me to picture

thanks,

Steve

gman2k

clogher71 wrote: »

Hi
I am in the same position now, did not leave enough room for insulation, I cannot find anything below 25mm.

I believe Hunton board can be got in 12mm.

bakerbhoy

soldsold
I will try and clarify

1. My blockwork was finished inner/outer leafs flush to each other.
2. When window opes were been measured the window supplier suggested adding extension ribs to the frame to allow for insulated reveal boards and still leave plenty of frame visible internally,but would leave a large frame vsible externally.I had been thinking of the external reveals being insulated so no problem there.
3.The cavity in the opes was closed with 30mm xtratherm foil board and gaps filled wth expanding foam.
4. Windows were then installed and again gaps filled with the foam.
5.Damp coarse was then siliconed to the outer edges of the frame
6.Phenolic boards 30mm were fitted to the external reveal with mushrooms and edges siliconed.
Expanded metal was used over the boards to help with mortar adhesion.
7.External reveals were plastered.

INTERNAL REVEALS
1.Reveals were taped with airtighness tape, all sides/top /bottom to frame and skim coated to blockwork.
Tape i used was contiga.
2.Insulated boards were then applied to reveal

onq

Possibly off topic for thsi particular query I know, but I think its related, given that insulation details at reveals are being discussed

What provides the cavity barrier function in these details - the fire insulation, if you will?

I'm thinking of TGD B http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,1640,en.pdf

Diagram 17
Masonry cavity walls excluded from provisions for cavity barriers
Table 3.2 Par. 3.3.3

The insulation exclusion refers to insulation in the cavity, not insulation between the habitable space and the cavity.

A tight-fitting timber window frame seals the cavity, or a sub-frame.

Alternatively fire retarding material can fill any gap between the frame and the cavity, or you can use an insulated fire rated cavity closer.

But filling the gap with any insulation other than Rockwool seems to be non-compliant.

I'm thinking particularly about this yellow foam stuff you see everywhere these days - is this mean to be fire-retardant or intumescent?

ONQ.