# Forum Home Renovation Cladding  Ply bracing behind cladding

## turbopsi

Can anyone please advise whether covering all the walls in ply bracing could introduce any issues such as trapping any internal condensation trying to make it out through the walls and out through the wall wrap? 
Wall materials in order from internal to external will be : 10mm plasterboard internal lining, insulation batts, 4mm ply bracing, breathable / vapour permeable house wrap (Procter wrap or James Hardy (HardieWrap weather wrap), cavity batten, external cladding (mix of horizontal corrugated and vertical grooved CFC boards). 
The reason I'm thinking about covering the walls in ply bracing is to have a uniform flush finish across all studs as the walls are already specified to have bracing in some areas. 
Alternatively I could cut the bracing into strips but thought using full sheets would save some time. 
Thanks.

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## CraigandKate

Doing this currently, and I have done full sheet ply bracing everywhere, the ply is certainly vapor permeable so not worried about that at all. 
What I do think is worthwhile is using a foil reflective wrap instead of the breathable membranes especially on the North/West sides of the house, you want to reflect the heat on those and that is not something the house wraps seem to do, hard to find firm information however. 
I am actually using Kingspan permishield 6.5 between ply brace and 25mm battens then between the batten and weatherboard I am also considering using another non foil permeable house wrap as that will make my window flashing's work properly.

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## JB1

Is any reflective foil wrap permeable? 
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## pharmaboy2

> Is any reflective foil wrap permeable?

  Well, the manufacturers of the foil with holes in it claim it's permeable and waterproof, but the manufactures who specify for their system do not recommend the old school holed foil wrap. 
im not convinced that foil has any heat advantages behind cladding, unless that cladding is steel, because the steel re radiates heat through it, timber, fc etc don't create radiation they transfer via convection

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## turbopsi

> Doing this currently, and I have done full sheet ply bracing everywhere, the ply is certainly vapor permeable so not worried about that at all. 
> What I do think is worthwhile is using a foil reflective wrap instead of the breathable membranes especially on the North/West sides of the house, you want to reflect the heat on those and that is not something the house wraps seem to do, hard to find firm information however. 
> I am actually using Kingspan permishield 6.5 between ply brace and 25mm battens then between the batten and weatherboard I am also considering using another non foil permeable house wrap as that will make my window flashing's work properly.

  Thanks, can you share some info on "make my window flashing's work properly". Thanks

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## turbopsi

HardieWrap seems to be the only wrap out of the "breathable" type that advertise a reflective property as well. "Triple shield". I was thinking this or the Enviroseal ProctorWrap Residential Wall but no mention of any reflective properties. 
HardieWrap. https://irp-cdn.multiscreensite.com/...%2014%20v2.pdf   https://irp-cdn.multiscreensite.com/...4%20-%20LR.pdf  
Enviroseal ProctorWrap http://www.proctorgroup.com.au/proctorwrap-rw/

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## DavoSyd

> HardieWrap seems to be the only wrap out of the "breathable" type that advertise a reflective property as well. "Triple shield". I was thinking this or the Enviroseal ProctorWrap Residential Wall but no mention of any reflective properties.

  after I looked into the wall wraps available, it is very important you get the wrap that is suited to your house's actual climate.   https://www.bradfordinsulation.com.a...election-guide 
what climate zone are you in? and do your individual site anomalies mean that your 'zone' is modified?  https://www.bradfordinsulation.com.a...ctor.pdf?la=en

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## CraigandKate

Sorry, was short on time the other day, in the aluminium windows I have there is a recess for a building/foil wrap or flashing to sit into but with the extra battens to create the cavity it is obviously not inline with the outside of the wall and my permishield. For that reason I am thinking that I will wrap outside the battens and run that into the window recess to create a extra water barrier to prevent water ingress into the cavity. 
You can possibly see the recess in this photo, battens are still to go on obviously.    
That Hardiewrap looks to be foil based anyway. 
This is what I am using:  https://www.kingspan.com/au/en-au/pr...ll-permishield

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## turbopsi

> after I looked into the wall wraps available, it is very important you get the wrap that is suited to your house's actual climate.   https://www.bradfordinsulation.com.a...election-guide 
> what climate zone are you in? and do your individual site anomalies mean that your 'zone' is modified?  https://www.bradfordinsulation.com.a...ctor.pdf?la=en

  Thanks for that. We re in the Shire of Mitchel (VIC) which puts us under "Cold". Funny that I called their hotline and they advised I was in "Temperate"

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## turbopsi

> Sorry, was short on time the other day, in the aluminium windows I have there is a recess for a building/foil wrap or flashing to sit into but with the extra battens to create the cavity it is obviously not inline with the outside of the wall and my permishield. For that reason I am thinking that I will wrap outside the battens and run that into the window recess to create a extra water barrier to prevent water ingress into the cavity. 
> You can possibly see the recess in this photo, battens are still to go on obviously.    
> That Hardiewrap looks to be foil based anyway. 
> This is what I am using:  https://www.kingspan.com/au/en-au/pr...ll-permishield

  Thanks, a bit hard to see the detail in the photo. Can't see my to expand the pic. Any reason why you didn't go for the more traditional wraps? Are you also putting bulk insulation in the walls?

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## CraigandKate

Yeah sorry mate was the best I had available at the time I will get some more pictures over the weekend, need to test out the process on a window anyway to make sure it works. 
Few reasons for using the permiwall, it obviously has a better R value than just regular foil as it is double sided with the foam in the middle and with my lightweight construction I wanted to get as much insulation in as possible. Also there is no firm data on this but I am reasonably sure it will make an appreciable difference to sound transmission through my walls. I don't live right next to but am reasonably close to a train line that runs freight trains and I think having that isolation between the stud wall/ply and battens/weatherboards will assist with blocking some noise.

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## TheHammer

What type of weatherboard. What type of battens are you using?

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## CraigandKate

I have some 25x40mm KD Harwood battens (just happened to pickup a cheap pack) and am using Baltic pine bullnose weatherboards. Will get some pics up over the weekend.

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## CraigandKate

Here we go, close up of the recess that is all the way around my Rylock windows, it is designed to have the building wrap run into it.   
This is with the 25x40mm batten next to it, which the weatherboards will be attached to. I am also using standard 31x31 internal stop to frame around all the windows.

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## turbopsi

Thanks for the pics

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## manofaus

how do the weatherboards finish up to the windows? are you going to add architraves?

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## CraigandKate

Using 31mm x 31mm internal stop to frame the window then butting the weatherboards up to the internal stop and caulking it.

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