I am close to fitting the windows into my extension and after some advise/comments.
Construction consists of 145mm timber frame clad in 9mm OSB,50mm cavity and then finished with 100mm concrete blocks.
Planning to proceed with the windows as follows:
1.Cut cill to length and glue on end caps.
2.Bed cill in silicone and fix to timber frame taken care not to distort.
3.Apply bead of silicone to back edge of cill and set window into position.
4.Centralize window in hole and plumb and level, hold in position with
spacers/wedges.
5.Fix window to timber frame using galv straps provided,150mm in from corners
and 450mm max centres again taken care not to distort frame.
Now for the questions!
I have 10mm clearance on the opening and frame,
Should I pack the cill up by 5mm or let it sit on the timber frame leaving the 10mm at the top?
Does the window then get screwed to the cill or will the silicone be sufficient to hold it, bearing in mind it will also be held in place by the straps?
And finally what would you use to fill the 5mm gap silicone or expanding foam? if the latter, does this allow much for expansion?
Sorry its a bit long winded trying to explain as fully as I can.
Forgot to mention, the window will protrude from the timber frame outwards by 50mm and some 2"x2" timber with DPC stapled to its face will go around the perimeter of the frame for a fire stop.
Construction consists of 145mm timber frame clad in 9mm OSB,50mm cavity and then finished with 100mm concrete blocks.
Planning to proceed with the windows as follows:
1.Cut cill to length and glue on end caps.
2.Bed cill in silicone and fix to timber frame taken care not to distort.
3.Apply bead of silicone to back edge of cill and set window into position.
4.Centralize window in hole and plumb and level, hold in position with
spacers/wedges.
5.Fix window to timber frame using galv straps provided,150mm in from corners
and 450mm max centres again taken care not to distort frame.
Now for the questions!
I have 10mm clearance on the opening and frame,
Should I pack the cill up by 5mm or let it sit on the timber frame leaving the 10mm at the top?
Does the window then get screwed to the cill or will the silicone be sufficient to hold it, bearing in mind it will also be held in place by the straps?
And finally what would you use to fill the 5mm gap silicone or expanding foam? if the latter, does this allow much for expansion?
Sorry its a bit long winded trying to explain as fully as I can.
Forgot to mention, the window will protrude from the timber frame outwards by 50mm and some 2"x2" timber with DPC stapled to its face will go around the perimeter of the frame for a fire stop.