Position of windows within timber frame section

[worldwidewebs]

When fitting the windows into a timber frame, does the window normally sit in the middle of the insulation or flush with the external face of the structure? I'm trying to work out the detailing for my stone cladding and the location of the window is going to affect what I do

[Crofter]

For best thermal performance it should be in the middle of the insulating layer.

'Normally' it seems every joiner I meet wants to put it sticking 50mm out in front of the insulation! They all think I'm crazy for wanting to install it in line with the insulation.

[Gone West]

My windows are fitted within the insulation layer to reduce thermal bridging.

[worldwidewebs]

Yes, I had noticed that the 'traditional' way wasn't particularly good! I came across a few postings back on ebuild where the windows had been installed flush with the outer OSB of the frame - I think Jeremy's is like this and I've also seen a schematic from MBC done the same way. But, I also read comments where people preferred a wider external reveal than this would give.

 

All of the first floor windows in our build will either have render or timber cladding around them. On the ground floor they will have stone slips cladding around them - with the slips affixed to blockwork. The only caveat to this is that one GF window will have render around it and 2 windows and the front door have stone to one side and render the other! (it looks better than it sounds).

 

I think it would look better if the 'rendered' windows had a deep reveal, so putting the window in the middle of the frame would be good. However, I have a bit of a detailing issue with a stone reveal, as by the time I've fitted 25mm battens, 12mm cement board, 5mm adhesive and 40mm stone slip I'd be covering the entire width of the window frame. I know I could always fit an additional 40mm trim to the window, effectively making the frame wider but it feels like I'm fudging it!

 

If the windows are fitted flush with the outer face of the timber frame, the stone problem goes away as I can complete any small reveal detail with an aluminium trim profile. The downside is that the rendered reveals are much smaller - this may or may not be an issue.

 

Thinking about it (typing this is helping actually), what would be good to see is images of rendered walls where the windows are fitted flush to the outer face of the timber frame, as I think getting the detailing right with windows in the middle of the frame could be a right pain!

 

 

[ProDave]

 

 

 

 

Re your "making the frame wider" Our frame was deliberately made 50mm to wide and too tall. The idea being the window opening was lined with 25mm kingspan and then the window fitted.  Could a detail like that work for you allowing a greater width outside the window for the cladding detail?

 

Our windows are set half way in the frame, and half way proud in front of the frame, but then the walls are clad with 100mm thick wood fibre board and then rendered, so arguably the whole window is within insulation.

 

Edited July 24, 2016 by ProDave
Edited to add a couple of pictures

[worldwidewebs]

4 minutes ago, ProDave said:

Re your "making the frame wider" Our frame was deliberately made 50mm to wide and too tall. The idea being the window opening was lined with 25mm kingspan and then the window fitted.  Could a detail like that work for you allowing a greater width outside the window for the cladding detail?

 

Our windows are set half way in the frame, and half way proud in front of the frame, but then the walls are clad with 100mm thick wod fibre board and then rendered, so arguably the whole window is within insulation.
 

 

I'm not sure to be honest - it's an MBC frame so I suppose I get what I'm given!