Windows and render

[23vc]

Hi
On my extension I was planning on fitting the new windows first, before rendering the blocks up to them with a corner bead and a narrow reveal.
Then I thought replacing them in future would be a nightmare as it would mean the render around them and the corner beads would have to be removed.
Still can't think of a better way, is that how it's normally done?

 

[garyo]

That's how I'm doing mine. I guess you might be able to sacrifice the internal plaster instead, but it's all much of a muchness...

Are you going to silicone them in or just foam them then trim off the excess before rendering?

 

[23vc]

I've only ever siliconed windows before, but every time I see any nowadays they've *always* got foam around them. I thought it may be some thermal requirement but my bco didn't think so.
So I'll probably do a bit of foaming just to make it look the part
Not sure which foams best for this, don't want anything that's going to go beserk, any recommendations?

 

[garyo]

I always silicone mine from the outside then foam from the inside using gun-grade foam - seems like an easy way to add another layer of draft reduction and secures them in place.

I'm not sure if there's much point in the silicone if rendering though?

 

[23vc]

Yeah, I'd probably silicone after rendering and painting ... I think

 

[oldbutnotdead]

The foam is put in so window fitters can bash off a whole house in a day. Knock out old windows, put in new ones with min 10mm gap to structure (to allow for shoddy rapid measuring. Foam, leave it 30 mins, stick a few screws in, whack some pvc strips over the gaps and away you go. If you're lucky they'll include solid bay poles and actually make sure they're supporting something not just flapping in the breeze.

(Done some doors and windows myself- took way too long but they fit properly and there isn't too much frame for the amount of door/window. Had 'window fitters' to do the bays but they made such a dogs breakfast I binned them off and finished the job myself. Finally found a trustworthy builder who supplied and nicely fitted French windows (as part of a larger job) for a very good price)

 

[garyo]

Had 'window fitters' to do the bays but they made such a dogs breakfast I binned them off and finished the job myself.

I've done that too when I saw that their idea of 'making good' was superglueing plastic strips everywhere. I do my own nowadays with packers and concrete screws, but then always solidify them in place by filling the 5mm gap with foam.