I'm insulating all the walls. It's single brick . I will use rockwool r2.5 acoustic batts
Do I need a vapor barrier filt behind the batts for extra protection? I do live in melbourne
thanks
Welcome to the Bunnings Workshop community @michaeljb. It's fantastic to have you join us, and many thanks for your question about installing insulation.It's important to have sarking as it prevents your insulation batts from coming in contact with the bricks and mortar and wicking moisture from them to the timber frame. You can retrofit Ametalin 1370mm x 30m VapourTech Brane VHP Vapour Permeable Wall Insulation between studs. Measure the width between your studs and add 100mm to that. Cut the sarking into strips and use a staple gun to staple 50mm to the side of one stud at the back. Place a staple every 200mm. Transfer across to the next stud and staple it to the side of that one. Repeat this across the span. You'll then be able to install your wall insulation.
Here's an image of how it's done on floor joists, and it will be the same with your wall studs.Please let me know if you have any questions.Mitchell
I did found some information and it says I have to place it next to the internal wall lining? That means I have to also put it in between the gyprock and insulation batts? Ametalin recommended that in colder climates like Melbourne
Maybe I'm reading it wrong.
I spoke with Ametalin technical support, and I have advised what they suggested, @michaeljb. There was no mention of needing to line between the batt and wall lining. If you can link me to the information you've come across from them, I'd be happy to follow up for qualification.
Mitchell
How does this work with the electricals in the wall? Do you go over it? Under it?
Welcome to the Bunnings Workshop community @NadiaTee. It's great to have you join us, and many thanks for your question about installing sarking.That would depend on where the wiring is positioned in the wall. There's no reason why the sarking should go over or under it; the decision would be down to what's easier.
When working around power, it is exceptionally important to ensure any fixings for the sarking do not damage the cable. If in doubt, I recommend you enlist the services of a professional.Please let me know if you have any questions.Mitchell
Hi Mitchell,
Thanks for explaining how to install the sarking. I have a couple of questions:
1. How do you do the top an bottom part? 50mm also? So if my wall is 2.4m, the sarking needs to be 2.5m long
2. What do you do for overlapping if the sarking is only 1.35m?
Thanks
Hi @jose17,
A warm welcome to the Bunnings Workshop community and thank you for your question.
At the top and bottom, you would also add a 50mm turndown to staple into the top and bottom plate. You will need to make a relief cut in the corner to allow the sarking to sit flush against both surfaces. You can tape up this cut with Reinforced Insulation / Ducting Tape to prevent thermal transfer through this relief cut.
Ideally, you would use this Ametalin 2740mm x 30m VapourTech Brane VHP Vapour Permeable Wall Insulation so that there are no joins, but if need be, you would tape any joins with Reinforced Insulation / Ducting Tape.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
Hi Jacob,
Thanks for getting back to me. The 2740mm x 30m roll is out of stock everywhere in Melbourne, not sure if there is a supplier issue or Bunnings doesn't stock it any more.
It appears the 2730mm roll is not stocked in those stores. You may want to speak with our helpful Special Orders team at your local store, as they should be able to order some in for you. Alternatively, as Jacob mentioned, you can tape lengths together to achieve your desired height.
Please let me know if you have any questions.
I am looking at retro fitting wall batts to a weatherboard house as we are getting rooms re-plastered.
We are in regional Victoria near Seymour.
So would I be right to put vapour wrap between the weatherboards and the wall batt.
Do I need an air gap between the wrap and the weatherboard or is it ok to let the wrap be stapled up against the weatherboards. Then I would place the batts between the vapour wrap and plasterboard.
There is only about a 75mm cavity
Cheers
Hi @zippyf,
Welcome to the Bunnings Workshop community, it is fantastic to have you with us.
It would certainly be worthwhile to include a vapour barrier between the weatherboard and the batts, but you'll have to let me get in touch with Ametalin, our main supplier for building wraps and vapour barriers, when they reopen tomorrow for the particular method that they would recommend.
Please bear with me, I will get back to you as soon as possible.
Thanks JacobZ
And I guess if the vapour barrier is best or a breathable product. But the big question is the air gap or not.
Unfortunately, the answer I received from Ametalin is that the only effective way to protect the cavity from moisture entry is to remove the weatherboard, install a membrane over the studs, with the Ametalin VapourTech Brane VHP being their recommendation for your climate area. You would then need to install battens over the studs to create an air gap, then reinstall the weatherboards over the battens.
This is because if you were to retrofit the membrane from the inside, it would not cover the outside of the timber studs, which would in turn allow moisture transfer through those timber studs, which would then end up in the cavity, which has the potential to cause mould and further issues with the insulation batts.
The other issue that arises, is that you have a 75mm cavity and the thinnest batts that are available are 75mm thick, so you would not have any room for an air gap anyway.
Unfortunately, the best suggestion I have is to speak with an insulation company for their advice. They may have experience insulating older homes that weren't designed for modern building standards and will be able to offer a solution that will work for you.
Sorry I couldn't be more help.
