Double glazing a shed. Out of my depth.

[Grahamshed]

I am more usually found in the turning section than here.
I am building a wooden shed / greenhouse. 4x2 construction with wood slats over.

I am using old house upvc double glazing units into the 4 x 2 framing and have heard that you can just hold them in place with expanding foam squirted into the gap around the UPVC frame. Is that correct ?

 

[Steve Maskery]

Sure, PU foam will hold them securely, but how are you going to ensure that the frames stay in place while the foam cures? I'd use a couple of 4" screws in each side first.

 

[Grahamshed]

Thanks for that Steve.

 

[RobinBHM]

Im assuming by upvc double glazed units you are referring to upvc windows that take double glazed -either with an opening sash or direct glazed.

The best way to fix, is through the upvc frame with screws into your studwork. Ideally use plastic frame packers, these are wedge shaped plastic packers with an open ended slot that goes over your frame screw. Timber packers also work but they need to be adjacent to the screw. When tightening the screws be careful to avoid distorting tbe frame. If your windows have openers you may want to wedge the frame in place, fit the sashes, open and close the sashes and adjust the frame for squareness or wind be screwing in.

It is possible to wedge a window in place then foam up, but you risk squirting in too much foam which may cause frame distortion.

 

[skipdiver]

Was about to make the same comment as Robin. Too much foam will distort the frames, so take it easy, though you can wedge and foam fix windows. I've done it before a few times. Wedges need to be placed where they won't bow the framing. Corners and where the transom is are good spots. You can also place a piece of timber between the frames where the glass sits to stop it pushing in if you get too much foam behind the frames. Having said all that, if i was fixing into a timber frame, i'd just use screws.

 

[Grahamshed]

These frames already have the glass in and from previous experience I am reluctant to take it out.

 

[Steve Maskery]

Ah, I see. So you can't get into the side to screw, is that it?
In which case you could screw the other way, through the stud and into the UPVC, just get your length right.
Or just wedge it securely so there is no chance of it moving and foam it up. Provided that there is room for the foam to expand outwards, as opposed to only towards the frame, then you should be able to do it without distorting the frame.

 

[ComfortablyNumb]

Using foam will fine just use sparingly and allow it to expand or you might make the frames bow. I removed a upvc front door that was foamed in and it would have survived ww3 I had to cut it out with a recip saw