Ben100 Posted yesterday at 14:37 Share Posted yesterday at 14:37 Hi, I'm replacing my old bay windows and have questions about how the new ones should sit. The window sills on the new windows are shorter than the old ones, so the windows need to sit more forward on the brickwork. This is the bay window space and new window. Is the sill ok to sit like this below? And is it ok for the middle of the window (not recessed) to return to the brickwork? Or does it need to sit more like this? Thanks! Ben Link to comment Share on other sites More sharing options...
JohnMo Posted yesterday at 15:00 Share Posted yesterday at 15:00 What's going inside the house or within cavity with respect insulation? Ideally the window should straddle the insulation Link to comment Share on other sites More sharing options...
Gone West Posted yesterday at 15:09 Share Posted yesterday at 15:09 The sill should overhang by at least 30mm. It doesn't look as though the sills are deep enough. 1 Link to comment Share on other sites More sharing options...
Ben100 Posted yesterday at 15:35 Author Share Posted yesterday at 15:35 35 minutes ago, JohnMo said: What's going inside the house or within cavity with respect insulation? Ideally the window should straddle the insulation I'm planning to fill the void with foam. S it looks like the window needs to sit back a bit more. Link to comment Share on other sites More sharing options...
Ben100 Posted yesterday at 15:36 Author Share Posted yesterday at 15:36 26 minutes ago, Gone West said: The sill should overhang by at least 30mm. It doesn't look as though the sills are deep enough. Yeah, I was thinking that. Maybe I need to replace the sill and sit the entire window back a little. 1 Link to comment Share on other sites More sharing options...
JohnMo Posted yesterday at 15:54 Share Posted yesterday at 15:54 17 minutes ago, Ben100 said: planning to fill the void with foam. I would consider EPS beads, they will self drain any water away and gravity will fill any voids fully. 1 Link to comment Share on other sites More sharing options...
JohnMo Posted yesterday at 16:02 Share Posted yesterday at 16:02 The window really needs to straddle the insulation Some notes on here https://nhbc-standards.co.uk/6-superstructure-excluding-roofs/6-7-doors-windows-and-glazing/6-7-3-in-service-performance/#:~:text=In cavity masonry walls%2C doors,layer of the external wall. Link to comment Share on other sites More sharing options...
ETC Posted yesterday at 17:03 Share Posted yesterday at 17:03 Get rid of that shit cement strap pointing for a start otherwise you’ll end up with spalled brickwork. 1 Link to comment Share on other sites More sharing options...
Gus Potter Posted 19 hours ago Share Posted 19 hours ago 4 hours ago, ETC said: Get rid of that shit cement strap pointing for a start otherwise you’ll end up with spalled brickwork. No mincing from ETC here on the pointing and I agree. 6 hours ago, Ben100 said: The sill should overhang by at least 30mm. It doesn't look as though the sills are deep enough. NHBC recommend 40mm of a drip which is what I spec as sometimes the render etc are a bit out of line. Your starting point is to work out how you are going to insulate the reveals, cills and head of the window. Then make sure you can fix the window securely and last make sure it is all weather tight with DPC etc. It's OK to mount a window on the outer leaf. Velfac windows adopt this principle. Have a look at their detail. Link to comment Share on other sites More sharing options...
Ben100 Posted 9 hours ago Author Share Posted 9 hours ago 15 hours ago, ETC said: Get rid of that shit cement strap pointing for a start otherwise you’ll end up with spalled brickwork. Yep. It’s on the list of jobs. Link to comment Share on other sites More sharing options...
Ben100 Posted 8 hours ago Author Share Posted 8 hours ago So I guess my two options are to get a longer sill and sit it over the insulation or install it on the outer leaf of brickwork. Link to comment Share on other sites More sharing options...
Gone West Posted 5 hours ago Share Posted 5 hours ago 3 hours ago, Ben100 said: So I guess my two options are to get a longer sill and sit it over the insulation or install it on the outer leaf of brickwork. Yup, if you get a deeper sill there will be a little less thermal bridging but it depends on whether it's worth it for you. 1 Link to comment Share on other sites More sharing options...
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