Which airtight tape is needed?

[ruggers]

Which airtight tape is best for window reveal cavity closers to blockwork?

 

I need to start buying air tight tape for various areas of the build, but first up, i need to order some asap to seal the plastic cavity closers to the internal block work reveals before the windows get fitted next week. 

 

I've just realised I'm going to need to tape one side of the closer before the frames go in. I'm having the frames set back into the cavity by 25mm, so window reveal fixing straps are being used, these will over lap the closer, meaning taping later wont make a decent seal.

 

Siga fentrim was suggested for some areas but its very expensive.

 

Just to add, all block work reveals are painted in airtight paint and closers will be modified to be thicker.

[Nickfromwales]

You don't tape to blockwork.

 

You need to parge the blockwork, to get it flat and uniform, and then paint it with liquid airtight membrane (assume Passive Purple from Intelligent Membranes?) and then you tap to that.

 

If you've PP the bare blockwork then that's less than great as the pours of the blockwork will allow air to pass behind the tape.

 

A pic of what you have would help, but, tbh, you just get the windows installed and then airtight afterwards, which reduces unnecessary work and effort.

 

 

This was one where I got the builders to fully parge the woodcrete ICF, as it's pretty dogshit unless you do the lot, and then PP over. Then they foamed, then they taped.

 

Very difficult project where I was principal consultant, but the builders were really good guys and we got an initial 0.88 ACH, then a bit of 'go find the leaks', and then a final test at 0.66 ACH (as built, end of project test) which was really not expected.