How to fit window that's slightly too small?

[ilikewatchingtv]

Hi all,
I really need to replace the rotten single glazed window in my kitchen - I'm on an incredibly tight budget and have been scanning eBay and other sources for a suitable used unit.
I have spotted a really cheap window, but it is about 30mm smaller on both the width and height (with the cill fitted). Is there any simple way to make this fit, or should I just keep on looking for something more suitable?
I had wondered about fixing a board on top of the opening below the cill to reduce the gap, then just gunning foam into the 15mm gap on either side of the window and letting this cure before fully tightening the fixings.

 

[crank39]

You can make up the difference with a 'frame extender' usually called 'clip on' or 'add on' in the trade, google these terms and you'll see what i mean, it might take a trip to a friendly local DG company who could sell you some

 

[ilikewatchingtv]

You can make up the difference with a 'frame extender' usually called 'clip on' or 'add on' in the trade, google these terms and you'll see what i mean, it might take a trip to a friendly local DG company who could sell you some

Cool, thanks! I guess I just need to get my hands on the window and find out what profile it is, or are these clip ons/add ons universal?

 

[crank39]

Correct they are profile specific but seeing as they're screwed on you can normally get any to fit any profile, don't forget the frame depth too when thinking about sourcing add on's, most frames now are 70mm thick so look for add on's for a 70mm frame

 

[masona]

If you're having problem finding the right profile you might get away with using coupler which is similar when they join the 2 frames together, they're normally 15mm