Filling a 40 mm window frame gap.

[Dodgyrog]

Replacing an old alu window with UPVC and reducing window width at same time by a full block length but long story short the new opening ended 40mm more than the new window. Height (1.2m) is fine. If I leave 5mm at one end it's 35mm to fill....or do I centre leaving 20/20?. I'm thinking that's too wide for just foam or mortar? Being new block it's a nice clean straight edge and it'll be rendered over so any / best options appreciated. Got a load of hardiebacker board lying around if some strips of that would work, but want to make sure I do it right. Ta.

 

[noseall]

Replacing an old alu window with UPVC and reducing window width at same time by a full block length but long story short the new opening ended 40mm more than the new window. Height (1.2m) is fine. If I leave 5mm at one end it's 35mm to fill....or do I centre leaving 20/20?. I'm thinking that's too wide for just foam or mortar? Being new block it's a nice clean straight edge and it'll be rendered over so any / best options appreciated. Got a load of hardiebacker board lying around if some strips of that would work, but want to make sure I do it right. Ta.

x2 15mm UPVC knock-on pieces each side of the window.

Most people build the opening THEN have the window made to suit.

 

[Dodgyrog]

x2 15mm UPVC knock-on pieces each side of the window.

Most people build the opening THEN have the window made to suit.

Cheers - but I want to render over those UPVC strips - is that ok to do? Will I need to coat them ? - don't want them showing either side of the frame or wont match other windows. Plus thats a trip out somewhere and I'm a bit isolated.

Couldn't build the opening first as the room is in constant use, new window delivery was a few weeks, then when came to fitting had to address something on the opposite side reveal to the new blocked up side which took out that 30mm.

 

[Notch7]

Cheers - but I want to render over those UPVC strips - is that ok to do? Will I need to coat them ? - don't want them showing either side of the frame or wont match other windows. Plus thats a trip out somewhere and I'm a bit isolated.

Couldn't build the opening first as the room is in constant use, new window delivery was a few weeks, then when came to fitting had to address something on the opposite side reveal to the new blocked up side which took out that 30mm.

if you are covering up the packers anyway you could use anything suitable -a bit of pressure treated batten would be fine. Obviously plastic is ideal as its rot proof and same as windows

as far as rendering goes -butting up to plastic trims is no different to butting up to a upvc window

 

[noseall]

^^^^^^^^^^^^^^
wot he said