Jul 29, 2019 9:10 pm
Im shocked at the lack of sill flashing options and window flashing options in Australia.
In the US they use products such as Dupont flexwrap over the vapor barrier but so little resources here.
Does everyone just ignore this step. I can imagine there are thousands of rotted frames due to this?
Re: Sill flashing and window flashing4
Jun 24, 2020 6:04 pm
Are you after a product like this?
Easy enough to find with google. Australia is warmer and houses less insulated than USA. There are some things Australia is still catching up with. A vapour barrier is something that only risen into the consciousness in the last 10 years let alone how to maintain it.while building.
Re: Sill flashing and window flashing5
Jan 04, 2021 10:01 am
yeah I hear you Michael. Try and get any straightforward information about how to build something right in Australia and it's wrapped up in obscurity - we have to pay $100 to get the instructions from SAI Global. Have a look at this from the National Construction Code - Im still uncertain where to get the tape products though, Ive wrapped the building in ametalin brane. Im an owner builder
Re: Sill flashing and window flashing6
Jan 04, 2021 10:03 am
Re: Sill flashing and window flashing7
Jan 04, 2021 11:20 am
this is a useful link frombradford proctorwrap: https://www.bradfordinsulation.com.au/~ ... .pdf?la=en
Re: Sill flashing and window flashing8
Jan 05, 2021 8:18 am
Whether your membrane needs to be breathable or not depends on your climate zone and how the building is conditioned.
Hot climates with a/c use an external vapour barrier with reflective foil whereas cold climates use a breathable external membrane and a internal vapour barrier.
CSIRO ran a great webinar recently but haven’t posted the link yet.
Re: Sill flashing and window flashing9
Jan 05, 2021 8:24 am
Hi gavEco, I thought the law was changed recently to require all membranes to be breathable? This is all new to me, and also the first I've heard of the internal vapour barrier and external breathable membranes. Does this mean two membranes in the same wall? I'm in NSW, cold climate.
Re: Sill flashing and window flashing10
Jan 06, 2021 9:51 am
I don’t know the current position of the law. I read the condensation guidelines in 2012 when they were publicly available. In general your wall system needs a vapour barrier on one side to stop the moisture getting in and a vapour permeable membrane on the other to let out any moisture that snuck in. You may use a reflective foil for your vapour barrier if you need to reduce radiant heat.
Which side the vapour barrier goes on depends on where the moisture and condensation risk is. It only matters when the space is not ventilated. In Canberra we lock up and condition our inside space in winter. The interior warm air holds moisture and the insulation can get cold enough for condensation. So we need an internal vapour barrier. It gets hot in summer but it’s mostly dry and fairly short so the condensation risk from internal cooling is low.
I’ve not lived in Sydney so you will need to weigh up the balance of a heating vs a cooling climate. I didn’t research it. I suspect that in more mixed climates where the vapour barrier goes may be contentious and potentially left out entirely.
Renew has a nice article below but it is focused on cold climates.
https://renew.org.au/renew-magazine/eff ... anagement/
I’ve found the current condensation guidelines which is a revision of what I read in 2012.
https://abcb.gov.au/-/media/Files/Resou ... s_2019.pdf
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