Installing new windows before EWI

william

Hi all.

Are there any technical issues or financial downsides to installing new windows (aluclad) now and then in 2 years time getting external wall insulation done for the whole house.

I understand that the windows have to be installed more forward in the opes which may look unusual for a while.

The EWI reveal boards will have to be a certain thickness (not sure how many mm) but is it necessary to get thicker window frames when ordering the windows? Would window companies know what’s required?

Lastly, would there be any issues with installing the cill extension when doing the EWI?

Thanks for help.

William

Calahonda52

The best solution, IMO is to do both together and hang the new windows on the outside of the wall, eliminates thermal bridging with narrow reveals.

BryanF

+1

MicktheMan

As above. But to add there is no reason you cannot get new windows now and move them out flush with outer walls when time comes to do ewi. But, imo, best to wait to do all together if you can.

william

Thanks for the replies. Was hoping to spread out the work but will take your advice.

listermint

I've done this myself.

My insulation requirements were 200mm . Mad I know but I'm a bit mad.

I removed the existing old timber windows boxed out the frames 100 mm from the house envelope so that the new frames would be smack bang in the middle of the 200 mm insulation layer and then reinstalled the timber frames temp few weeks till the new window were installed. Once done I then launched into the insulation installation.

Make sure the window boxing and the frames are made properly airtight or else it's all pointless. That means airtight tapes and membranes

Also please do good research on aluclad in Irish climate. You might think they look nice now but unless you are going to give them maintenance every so often then don't get them. We went with pvc because I was not willing to maintain timber windows again. Absolute nightmare.

Calahonda52

I would echo the thoughts on aluclad in irish climate, which is really too humid for aluclad, moisture gets in behind and stays there, leading in time to the window rotting, maybe 10 years but well after the g/tee runs out

william

Thanks. Didn’t realise that about aluclad. Will take on board.