Build in windows? Information, help and advice on many architecture, self build and design problems and issues

[ihampshire]

Advice please! Am having extension built and doing a lot of work myself. Windows will be plastic so should they be built in, or measured and fitted after building is done? Thank you.

[Perry525]

I can never understand why people pay thousands of pounds for well made windows, only to have some lazy fitter make a bad job of fitting them.
So many fitters leave gaps round the frame for the warm air to escape and cold air to enter.
If you build them in, then they will be the devil to remove, better than having them fall out.
Properly fitted, you will end up with a warm comfortable room, a room that will save you a fortune on heating over the years.