[Greenbuilding] [BULK] Designy metal frame windows with good U-value?

[Ted Inoue]

I'm with Larry on this. Low expansion foam.
However, some manufacturers specifically state that your warranty will be
voided if the window fails and it is found that foam is used.
In my own home, I foamed all the windows *carefully*. spray in a thin bead
and wait until expansion has stopped. Do this several times, allowing the
foam to naturally expand into the space. The foam is dense enough too that
it will fully and evenly support the window.
I'm not sure about wood expansion however. If you foam the window like this,
then the wood expands, which it will, there may be distortion issues. With
just shims on the bottom, there's room for the window to move up and
sideways, so that would be safer. You'd have to make the call.

The other recommended practice is to use foam backer rod, which is
compliant. You can get this in a wide variety of widths and it will fill the
gap very nicely without stressing the window. They suggest caulking this as
well to ensure a fully air and water tight seal.

The fiberglass packing method is something currently frowned on because it
isn't air or moisture tight. Plus, bugs have a tendency to burrow into it.
I've pulled out a bunch of windows and the associated fiberglass mess and
would never allow this practice.

I'm a big Loewen fan, so I can't provide alternative suggestions there
either.

On 2/27/07, Lawrence Lile <LLile at projsolco.com> wrote:
>
> I debated the foam-in-shim-space issue with my contractor.  He said that
> he had seen window frames bow when filled with expanding foam, causing
> the sash to stick.  I have always used minimally expanding foam (there
> are two kinds) in these and have been fine.  I guess the answer is you
> have a risk of messing up your window with the foam.  Fiberglass can be
> stuffed in here, to good effect.  Jamb extensions or sheetrock returns
> allow a space for foam.  I still go with the foam idea, just don't get
> too aggressive about it, i.e. don't pump foam in there until it runs out
> the next hole.
>
> I ran foam around all the replacement windows in my old house (low cost
> vinyl double glazed units) without any issue.
>
> I think the foam also can cause more trouble in a larger window, more
> leverage.  Foam can exert quite a lot of pressure if you squirt it in
> too much.  I tend to err on the side of "foam everything"
>
> Can't help you with a "stylish" window, I think anderson is stylish
> enough.
>
>
> Lawrence Lile, P.E., LEED AP
>
> -----Original Message-----
> From: greenbuilding-bounces at listserv.repp.org
> [mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Dan
> Johnson
> Sent: Tuesday, February 27, 2007 12:40 PM
> To: greenbuilding at listserv.repp.org
> Subject: [BULK] [Greenbuilding] Designy metal frame windows with good
> U-value?
> Importance: Low
>
> Blomberg and Bonelli, two local California companies, put out
> clean-looking, hollow frame alum. windows that are really holes in
> the wall at R-1.3 or so.  A typical chunky Loewen or Andersen wood
> window is R-3. Anybody know of a "stylish" window with a frame this
> good? Asking on behalf of high-designy clients who want to "go
> green."
>
> Second question: does anyone recommend using expanding foam in the
> shim space between a window frame and its rough opening? Previously
> we caulked the outside of this space and stuffed the inside with
> loose fiberglass batting. Less infiltration with foam?
>
> Thanks, --Dan
>
>
> Dan Johnson
> danjoh99 at gmail.com
>
>
>
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