Upvc window problems

[Louylou]

Hi i am looking for some advice as to fitting windows for the first time I've come to a problem , I measured the external opening size and it is 910 mm wide ,The internal width is 1m so should I buy a 900mm window and add a 40mm extender to each side ,or is there another way thanks any advice be appreciated

 

[diy_fun_uk]

Most advice seems to state taking 3 x width and height measurements from outside (brick to brick, ignoring existing framing etc) then, using the smallest of each, deduct 10mm in total to give the required size. However I think this approach is based on some assumptions as to the existing cavity i.e. it's not always that straightforward.

Are you buying and installing the windows yourself or simply measuring to enable companies to provide a quote? If the former, some pics of the existing window setup from outside and inside (showing the edge i.e. where window meets the walls) would be useful.

Also, Googling something like 'how to measure UPVC windows' will throw up lots of sites offering advice, hints & tips.

 

[Louylou]

Yes i am installing myself i have measured external as I should and that will look great from the outside, but then there will be a 40 mm gap to the internal reveal from the edge of the window each side

 

[crank39]

You can't put a 40mm frame extender on each side of the frame as that'll make it 990mm wide and your opening is only 910mm, its very strange to have the internal plaster sizes wider than the brickwork size, unless its a box sash, some pictures inside and out would help

 

[Louylou]

Hi i can fit it from the inside then it will but up to the back of the external reveals, I'm replacing old wood windows add it a pic don't know it that helps

 

[crank39]

Yes that's fine it's as I expected as your not fitting between the brickwork but behind, yes using extenders is fine, saves trimming over a large void even if filled with foam