Dormer window replacement help/advice

[Reeves2k2]

Hi guys right need a bit of help please

I have a flat roof dormer in my attic constructed in the 80's typical build studded frame and plasterboard the window is old wooden and rotten so will be replacing it
I have the replacement window upvc type
And I have only just noticed this issue
The new window is the same dimension as the original timber one but the frame of the original is wider in diameter so once the new window is in place the internal plasterboard cheeks will be nearly flush up to the glass there is about 10mm max
The original as it is at the moment has barely any frame showing on the sides

I am a plasterer by trade so removing the plasterboards aren't a problem my question is I will need to widen the cheeks slightly by maybe 12.5mm on each side to make it all look symetrical from the inside

Can this be done or is there any trade tips that will help with the issue

Again the window will fit with the existing but the internal cheeks will look odd only having a little bit of frame showing on the sides and have more on the top and bottom

Thanks

 

[pinenot]

Depends what's behind the plasterboard. Assuming the frames have nothing packing the their faces, then nothing can be removed = no dimensional gain, which would therefore require reposition of the "cheek" frames.
There would be but one alternative I can think of in this instance, splaying/stepping the cheek ends to fit the new windows. View media item 62469 ...pinenot

 

[Reeves2k2]

Thanks for the reply I did have that same idea this morning as well

Luckily once the window went in there was e ought room to jiggle it about and even the frames up

I know have the most joyous of jobs trying to make the whole dormer watertight from the outside which will be no easy task as the cill sits below the tiles :-/