Hi there,
Long time listener, first time caller
We are about to replace the external cladding on our 1940's weatherboard house located in the inner northern suburbs of Melbourne. The house runs south to north so has a long exposed western wall which gets a lot of sun in summer.
We will be removing the old baltic pine weatherboards and replacing with bgc nuline fibre cement weatherboards.
Whilst the walls are open, I plan to install R2.7 insulation batts (already purchased) and wall wrap before recladding.
Regarding the wall wrap, I already have a roll of Tyvek HomeWrap(~2.75 or 3.00m high x 30m length) as well as a couple of rolls of sisalation wallwrap EXHD breather single sided foil (1.35M high x 30 or 60m).
Just wondering if there would be additional insulation or draught stopping benefits by using two layers of the wall wrap?
I've done a lot of reading online and my current thoughts about the wall construction would be this:
Option A: Batts + foil wrap + cladding
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layer 1) R2.7 batts - friction fit between the wall studs
layer 2) sisalation wallwrap with the reflective side foil facing inwards (would be directly touching the studs and insulation batts)
layer 3) fibre cement weatherboards nailed to studs
some other variations on this might be as follows
Option B: Batts + tyvek + cladding
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layer 1) R2.7 batts - friction fit between the wall studs
layer 2) tyvek homewrap (would be directly touching the studs and insulation batts)
layer 3) fibre cement weatherboards nailed to studs
Option C: Batts + foil wrap + tyvek + cladding
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layer 1) R2.7 batts - friction fit between the wall studs
layer 2) sisalation wallwrap with the reflective foil side facing inwards (would be directly touching the studs and insulation batts)
layer 3) tyvek homewrap over the top of the reflective foil
layer 4) fibre cement weatherboards nailed to studs
Option D: Batts + tyvek + thermal break + foil wrap + cladding
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layer 1) R2.7 batts - friction fit between the wall studs
layer 2) tyvek homewrap over the top of the reflective foil
layer 3) some sort of thermal break on top of the foil over the studs(e.g. the james hardie "hardiebreak" thermal strip?)
layer 4) sisalation wallwrap with the reflective foil side facing inwards (there would be a ~12 mm gap between the foil and the tyvek homewrap)
layer 5) fibre cement weatherboards nailed to studs
I'd be interested if anyone out there can make any suggestions for potential improvements to the above, which option they'd go for, etc.
thanks,
Tyrone