What are the thoughts on window placement.  I live in Western Canada typical winters often reach -30 degrees C and summers often reach plus 30 degrees C.  It seems that a number of window manufacturers offer an icf brickmold which has the full icf width jamb, but the glass pane is centered in the jamb.  My concern with this is that this basically eliminates the insulating component of the outer portion of the icf, because the thermal portion of the window would be in the middle of the concrete portion of the icf wall, thereby allowing exterior temperatures to either heat or cool the concrete surrounding the window.  Given that concrete transfers heat and cold with virtually no insulating capacity, is this not a big no no in my climate.

The other option is to go with a standard window with a 2 1/8" jamb with a 3/4" return and make my own jamb extensions.

Please note that the windows are all casement of fixed glass, triple pane, double low e double argon filled.

Please comment.

Thanks

Regarding thermal bridging, if you use icf bucks that issue is resolved.
Also if I'm not mistaken, when the glass itself of a window is located towards the conditioned space, the efficeicy of the window assembly will be at best.
I do believe I've read this somewhere on this forum.
When ordering your windows, if a drywall finish interests you, order the jambs with a drywall return.
Believe you me you'll have plenty left over. However, it is best to use water resistant drywall (same as in baths)
for there is a chance that condensation from window will stand at bottom (although no window will ever condensate.......not).

Hi Jojo, Although having the window closer to the conditioned space is theoretically more energy efficient, most of my clients (ok, all of them) want a big, large window sill on the inside - so the window ends up set closer to the outside, mostly brick, so standard brick molding back to the window. I haven't had any problems to date setting the window back, and typically have been using wood bucks to accommodate the placement. Although more work on my end, I make up 2 bucks (2- 2x6 frames in a 12" thick wall) to assist in reducing the thermal bridging. Keep in mind that once installed, your window should have a good 1/4" gap all around inside your RO, shimmed/flashed appropriately, then foamed in after the fact which also reduces the thermal bridging you are worried about. Good luck.

i am not terribly worried about the thermal bridging through the wood to the interior of the house because of about r 11 for the wood, I was more concerned with the thermal bridging between the outside and the concrete which would only have about an r1 due to the wood, and then the concrete would carry the thermal differences a much greater distance thereby minimizing the exterior insulation benefit.

The foam buck as thagreen states would eliminate this issue, however, I have always been concerned about the strength and durability of these types of bucks, any comments on this.

Also I am using nudura blocks

Thanks

jojo,
Here are some old threads discussing window bucks and trimming.

http://www.greenbuildingtalk.com/Forums/tabid/53/aff/4/aft/60495/afv/topic/Default.aspx

http://www.greenbuildingtalk.com/Forums/tabid/53/aff/4/aft/52284/afv/topic/Default.aspx

http://www.greenbuildingtalk.com/Forums/tabid/53/aff/4/aft/69764/afv/topic/afpgj/2/Default.aspx#50822

i cant access the last topic.  Thanks

Posted By jojo12 on 26 Sep 2011 04:20 PM
i cant access the last topic.  Thanks

Should come right up when you copy and paste the address. These are not hot links.

Thanks, but in my other post that you responded to jeepster found an error in the link and corrected it so I can now see it.  thanks for your info

You want to recess the windows, it makes them more efficient. If you mount the windows on the exterior they are the first thing the wind hits and the air infiltration is increased. Some manufacturer did a test a few years ago. Thet found that the air hitting a flat surface created an eddy that decreased the wind pressure against the window if it was recessed.

On the window section a while ago a rep for I think it was Fibertech agreed with this.