Hi folks,
I have a large enclosed carport area under half my house, and easy access to under the floor in the other half as well. Most of the electrical out wiring is tacked along various floor joists. The house floor is polished floorboards, and it's pretty cold in winter being in a valley in Tasmania. The roof is well insulated.
I was looking for a cost-effective and easy to DIY install option re insulation to provide some thermal insulation, draught protection, and a little muffling of acoustic noise like people moving about in other rooms. I'd prefer a non-allergenic/itchy/environmentally friendly option.
This is leading me to think polyester batts are the way to go. I hear they can be floppy though.
Any suggestions on the best ones to get and installation options?
Cheers,
B
Underfloor insulation: best batts?
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Why not look at foilboard its an aluminium covered fire resisitant foam costs around $30 a 2.4x1.2 sheet
We used foilboard. Quite easy to retrofit also
I've come back to this task after being distracted by other things
The trouble with foilboard and expol etc is they'd cost over $1000 in materials for a 100sq metres, compared to around $500 give or take a $100 for batts. I thought about polybatts, but they are also significantly more expensive and I've found modern glasswool (like the Earthwool brand) seem easy on the hands.
My joists are about 120mm deep - would it work better to get ceiling batts of about that thickness (eg. R2.5 at 115mm, or even thicker if cheaper and compress them 50mm or so) or wall batts which tend to be thinner (eg. R1.5 at 70mm . I'm planning to put up battens or netting to hold the batts in place, so batts would be likely to rest against that, with wall batts leaving a bigger air gap between batt and floorboards.
My floors are draughty around the skirting boards since I took up the carpets, so I'm wondering if the more batt thickness the better to block up draughts.
Are there recommended places to buy batts. buybuildingsupplies.com.au is a lot cheaper than I've found locally in Hobart...
And finally, should I be worried about rats nesting in the batts under the floor? I've seen some signs of rats in the roofspace so baited heavily...
Cheers,
B.
The trouble with foilboard and expol etc is they'd cost over $1000 in materials for a 100sq metres, compared to around $500 give or take a $100 for batts. I thought about polybatts, but they are also significantly more expensive and I've found modern glasswool (like the Earthwool brand) seem easy on the hands.
My joists are about 120mm deep - would it work better to get ceiling batts of about that thickness (eg. R2.5 at 115mm, or even thicker if cheaper and compress them 50mm or so) or wall batts which tend to be thinner (eg. R1.5 at 70mm . I'm planning to put up battens or netting to hold the batts in place, so batts would be likely to rest against that, with wall batts leaving a bigger air gap between batt and floorboards.
My floors are draughty around the skirting boards since I took up the carpets, so I'm wondering if the more batt thickness the better to block up draughts.
Are there recommended places to buy batts. buybuildingsupplies.com.au is a lot cheaper than I've found locally in Hobart...
And finally, should I be worried about rats nesting in the batts under the floor? I've seen some signs of rats in the roofspace so baited heavily...
Cheers,
B.
Although foilboard is more expensive it is self supporting so may be cheaper and easier to fix.
The R value only applies when the batts are uncompressed so there is no advantage in getting a thicker batt than the depth of the joist. Actually putting a 115mm bat in a 120mm deep space would give very similar results to filling the whole space with a batt as you will be creating a 5mm layer of still air which has insulating value.
My joists are about 120mm deep - would it work better to get ceiling batts of about that thickness (eg. R2.5 at 115mm, or even thicker if cheaper and compress them 50mm or so)
The R value only applies when the batts are uncompressed so there is no advantage in getting a thicker batt than the depth of the joist. Actually putting a 115mm bat in a 120mm deep space would give very similar results to filling the whole space with a batt as you will be creating a 5mm layer of still air which has insulating value.
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