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R values

What R value should I use?

This page on choice says 1.5 for the walls and 1.5 to 3.0 for the ceiling : http://www.choice.com.au/reviews-and-tests/household/heating-and-cooling/home-heating/home-insulation-buying-guide/page/r-value-what-is-it.aspx

However when I follow the link I read 2.8 for the walls and 4.1 for the ceiling: http://www.yourhome.gov.au/passive-design/insulation

However it also says there "Total R-value". Including the drywall and the cladding then?

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Comments

  • As much as you can fit in the walls without compressing batts, typically a 1.5 batt plus a building wrap (foilboard might be higher). In the ceiling...I'd go for at least R4 if you can...more the better. But the same rules of non-compression apply.

  • Hi John

    We looked this product gives you a total seal . http://www.foam-insulation.com.au

  • In the ceiling, what happens if you use two layers of 90mm instead of one layer of 180mm? Seems like that would actually be better (no gaps)?

  • Just use a R6 batt

  • Seano knows his stuff.

    Why argue? Just do it! ;)

  • I'm not arguing, I said can you use two layer instead of one. Seems you can, saw a video on it. So I'm going to try 1.5+2.5 in part of the ceiling and see if we can tell any difference.

  • John are you on floor boards , if so have insulated under the floor . Cheers

  • Good Point Mal

  • I'm thinking I will just encase myself in insulation. Cheaper.

  • JohnR said: I'm thinking I will just encase myself in insulation. Cheaper.

    Insulation & bubble wrap :-)

  • and a gimp mask!

  • JohnR said: I'm not arguing, I said can you use two layer instead of one. Seems you can, saw a video on it. So I'm going to try 1.5+2.5 in part of the ceiling and see if we can tell any difference.

    You will notice the difference...either with doubled insulation or a gimp mask. Assuming you are currently wearing neither.

    Wrapping yourself in insulation is quite silly. I once got partially wrapped in glass fibre insulation as a result of misadventure and the result begs one to query why it hasn't been used as a torture technique in some B grade action film...

    I also recall trying to install reflective film on the roof of the house on a sunny day and damn near getting killed by concentrated infra red reflected off the stuff as it shifted with the breeze...it was like being punched by a blast furnace.

  • No glass! Poly, nice clean green (literally) poly. Had enough of that have I just given myself a horrible respiratory illness feeling every time I come down from in the roof! Bagged most of the old glass today coff coff yes I wore a respirator gah is that what a gimp mask feels like? Graham enquiring minds... Don't need to know.

    Need to call the store tomorrow see if I can get some roofing battens along with everything else, funny how these little repair projects grow....

  • Speaking of reflective film is some better than others? Or are thaey all basically the same,

  • Some is better than others...I prefer the heavy duty woven plastic versions rather than the reinforced paper versions. It costs a bit more but is lighter and stronger and much easier to handle. http://www.insulation.com.au/products/reflective-foil-insulation-and-laminates/

  • I'm confused as heck. There is one for tile roofs, and one for metal roofs, and nobody can tell me what the difference is! Any ideas?

  • OK I found it. The emittance of the anti-glare face is 0.1 for the metal roof sarking, and 0.8 for the tiled roof sarking. The metal roof one says it's "double-sided". The emittance of the reflective face in both cases is 0.03.

    I have metal tiles. They are coated in something. ("Decromastic")

    :-/

    :-/

  • Decromastic - these guys say it's crap and replace it with colorbond - http://www.masterroofingaus.com/gallery--blog/decromastic-roofs-what-how-and-why

    :'(

  • I feel your pain. We had a similar sort of roof just without the bitumen. It was fairly awful but it didn't leak much because it had been laid directly over the original corrugated iron. Well...nailed to hardwood battens that were themselves nailed into the corrugated iron...if you can call that 'laid'. To their credit, they did survive the best part of thirty years...

    Use the metal roof product range. Don't panic about the roof...if it doesn't leak then it doesn't matter.

  • Seano said: it had been laid directly over the original corrugated iron. Well...nailed to hardwood battens that were themselves nailed into the corrugated iron...

    Dodgy Bros Roofing Co! Coming to you in all states and territories.

    Use the metal roof product range. Don't panic about the roof...if it doesn't leak then it doesn't matter.

    I've decided the Decra at least has the advantage that one person can repair it solo. Biggest problem is at the edges - poorly done flashing. I'll eventually get all of it sorted though...

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