Cut 1/2" off a UPVC window?

Hi folks,
I've got a UPVC double-glazed window that is perfect for my purposes except that it is 1/2" too tall. You might ask me why I don't make the opening bigger, but it's really not easy, as the house is built of hard stone, and there is a shaped stone sill at the bottom and a stone lintel at the top, both of which I'd like to avoid carving up.
I wonder if I can take 1/2" off the bottom of the frame with a circular saw. Once the window in place and securely bedded in with expanding foam, the fact that I cut 1/2" off is not likely to cause any problems, is it?
(The window is about 33" wide and 56" tall. The bottom half has a fixed pane and the top half has a top-hung opening.
Many thanks...
JD
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I would say no. The frame is hollow and contains square metal reinforcment pieces. These keep the frame stiff and catch the screws for the hinges etc You might be able to trim a very small amount off top and bottom so long as you don't cut into the hollow bit
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There are no hinges in the bottom half of the window. Unfortunately, shaving the ridges off the top and bottom isn't quite going to be enough.
JD
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Well then, it's a no no.
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I have seen it done at work.
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Adam


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On Tue, 26 May 2015 19:14:36 +0100, ARW wrote:

quite

By "professionals" no doubt.
How much more will be needed after the ridges have gone? If you don't want to hack bits of the stone work and I don't blame you if you don't. You appear to have two alternatives, lift the lintel or buy a window of the correct size. You might get away with removing a face completely but I wouldn't leave it like that glueing (aka solvent weld) a U shaped bit of uPVC into the void would give back much of the strength. Assuming any metal reinforcing allows that much to be taken off. You're unlikely to find a U channel of the corect width but this isn't sen so two L bits overlapped down the middle would do.
Lifting the lintel would mean removing a course above it, jacking up on acro props, packing the gap under each end and replacing the course above. Random stone would probably repack into the space, bricks or other fixed size materials would give a problem and if the mortar beds are visible look a bit odd as they halved or more in thickness above the window.
One also wonders why this window is 1/2" to high, unless you live in a "standard" modern box windows will be made to measure not off the shelf.

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Cheers
Dave.
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Some good suggestions there - thank you. Another option I wondered about was to see if I can get a local UPVC window maker to reduce the size of my window. Hopefully that would cost a lot less than the ?200 it would cost to have a suitable new window made from scratch.
It's an old Georgian stone house that has been rendered, so I am reluctant to raise the heavy stone lintel. Lowering the heavy stone sill might be an option. It would require less 'making good' afterwards.
I'll chew on it for a bit...
JD
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If the part you're going to be sawing into might be box section...
Before doing anything, drill a hole, or holes and inject high density polyeurethane expanding foam into the cavity. You could so position the holes to be sure that the foam has penetrated right through the cavity. Allow the foam to harden and then make the cut. You can then coat any exposed polyurethane core with a single coat of polyester resin with maybe a single layer of glass fibre surface tissue,
michael adams
...
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email.me:

Hi, Thanks for the expanding foam tip. That sounds like a good idea.
JD
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michael adams wrote:

If planing the ribs off isn't enough, then this is the most sensible suggestion, short of replacing it ...
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JD wrote:

The corner mitres are welded, by the time you cut it apart, avoiding any metal reinforcing, remove 1/4" from each upright and re-welded it, it would be 1/2" narrower as well as 1/2" shorter, and would need new glazing unit as the size would have changed.
I suspect they'd be more inclined to roll their eyes and offer to make you a new one ...
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Yes the construction of these varies so much I seem to recall. You might be able to avoid structure or maybe not. The other problem is one of the vibration cracking the glass, unleess you can remove it while working.
If you tried this on one I have in my kitchen, then only about 1 quarter inch would remove the bottom of the moulding that holds metal blocks that the screws go through to hold it all together. Brian
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Thanks for the tip, Phil. I may have to plane it down past the flat part beyond the ribs, so that the hollow is exposed, I would think this is a gamble worth taking rather than forking out for a new made-to-measure window.
JD
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On 27/05/2015 08:28, JD wrote:

Certainly sounds doable. I might stick to your original plan and use a circular saw, mainly because it's easier to get the accurate square cut you need by following a straightedge.
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I suggest you drill a hole first so you can see what depth you have to play with.
Mike
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1/2 inch is 12.5mm, planing the ribs off top & bottom should easily get you that?
Jim K
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