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| Green Building Bible, Fourth Edition |
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These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment. PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book. |
Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.
Posted By: bardoAside from the itching during fitting.
I wonder about the thermal performance of rockwool compared to sheepswool.
Will rockwall release moisture?
Posted By: PetlynThe expanded glass beads would be usable in direct contact with cable ducts or trunking without determent
" alt="" src="/newforum/extensions/Vanillacons/smilies/standard/bigsmile.gif"></img><img title="Posted By: bardobtw...n your straw bale home how did you detail the bathroom to reduce and deal with moisture?
Posted By: PetlynOverall areas is approx 115 M2 with an over all depth of about 700mm. I presume that would mean a lot of glass bead?
Posted By: PetlynWe have a minimum of 30m3 available which, over your square area and allowing for the joists in the space, would give you a depth of 30cm at an insulation value of 0.0661 W/(m-K). At this depth, one would have thought the insulation value itself beneath the floor would be sufficient which would allow the lower part of the void to be backfilled with a cheaper material before introducing the beads in their free-flowing form to fill the irregularities beneath and in between the joists.
Alternatively, you could consider using more of the beads which we obtained direct from the manufacturer in Europe - we can give you details of our source and as we said, a sample and spec sheet are available for your consideration.
Our beads at a very attractive price are available at £5000 for 30m3 and to fill the void entirely would seem to be an expensive option. The beads are indestructible and non-compressible and so will give a permanent result, warranting the use of an aggregate, such as pea shingle as the substrate with geotextile to separate?
The beds are available in normal big-bags holding approx 0.55m3 each and can be moved across a floor easily by two people for siting.
Hope all this helps.
Posted By: GreenPaddyOk, so JJI's in place, with 400mm gap to solum...
If you set say 9mm OSB onto the JJI flanges, then your Uvalues would worsen, to something like;
wool lambda 0.044 (typical cheap loft roll) = Uval 0.18 W/m2K
wool lambda 0.04 = Uval 0.17 W/m2K
wool lambda 0.032 = Uval 0.14 W/m2K
What about running a foil faced breathable membrane under the JJI's, running perp to the JJI's?
Start by fixing a timber 25x50 batten to the external block underbuild, at JJI underside height. Staple (and glue) the VPM to that batten, to give a seal to the wall. Then, VPM to first JJI, passing under it, bring the VPM up the vert face of the lower flange and onto the top side of that flange, fold back on itself, staple through the double thickness of VPM onto the top side of the flange, then go back down side of flange, and across to next JJI, passing under it, before repeating.
The foil should face the solum! That will give a well supported continuous layer, at full JJI depth, not losing the depth of the lower flange. You could actually let the foil VPM droop below the JJI's, by say 100mm, and even put 400mm of the cheap loft roll 44 (Uvalue for that arrangement = 0.12W/mK).
That's deff how I'd do it, and not just on paper, have done that on a previous project. Remember to fluff up the wool insulation as you install it, so it's got lots of air en-trained in it, and not squashed, as it comes out of the roll.
Posted By: GreenPaddyThe obvious answer is about 20%, but you're not asking that of course. All things being equal, I would go for the best Uvalue I could sensibly get. Usually cost or available depth sets the "sensible" limit, though Passiv Huas empirical data suggests something around 0.15 is a "sensible" limit. I go a bit below that, where possible, as passiv solar gain here in the Highlands can be a scarce commodity.
They are both good values (0.11 and 0.14), but here's the thing, the cost of the cheap loft roll 44 is much less than the reduction in thermal properties.
Comparing 100mm depth per m2 - loft roll44 = £2, rafterroll32 = £8
You could install the 400mm depth of LR44 (sitting in the VPM hammock) for much much cheaper than the 255mm depth of RR32 sitting on the OSB board, or indeed say 125mm rigid insul board.
Or slice it this way... say target Uvalue of 0.13 ish, the costs for full thickness of insulating material for each m2 of your floor would be in the order of;
- LR44 £8
- RR32 £24
- rigid PUR/PIR £20
So to the question of OSB mouse barrier. I'd take the large savings over the chance of the odd mouse, making itself at home. Pays your money, makes your choice. As usual, there isn't a RIGHT answer, you've got to set your own position on the specturm.
Posted By: GreenPaddyStaple (and glue) the VPM to that batten, to give a seal to the wall.
Posted By: GreenPaddywe fix for a lasting secure insulation base. If a membrane, would it need to be a vapour check type such as intello or a breather membrane such as solidex?Posted By: GreenPaddyThe obvious answer is about 20%, but you're not asking that of course. All things being equal, I would go for the best Uvalue I could sensibly get. Usually cost or available depth sets the "sensible" limit, though Passiv Huas empirical data suggests something around 0.15 is a "sensible" limit. I go a bit below that, where possible, as passiv solar gain here in the Highlands can be a scarce commodity.
They are both good values (0.11 and 0.14), but here's the thing, the cost of the cheap loft roll 44 is much less than the reduction in thermal properties.
Comparing 100mm depth per m2 - loft roll44 = £2, rafterroll32 = £8
You could install the 400mm depth of LR44 (sitting in the VPM hammock) for much much cheaper than the 255mm depth of RR32 sitting on the OSB board, or indeed say 125mm rigid insul board.
Or slice it this way... say target Uvalue of 0.13 ish, the costs for full thickness of insulating material for each m2 of your floor would be in the order of;
- LR44 £8
- RR32 £24
- rigid PUR/PIR £20
So to the question of OSB mouse barrier. I'd take the large savings over the chance of the odd mouse, making itself at home. Pays your money, makes your choice. As usual, there isn't a RIGHT answer, you've got to set your own position on the specturm.quote
- CommentAuthorhttp://www.greenbuildingforum.co.uk/newforum/account.php?u=6193" >GreenPaddy
- CommentTimeOct 24th 2019
Hi Bardo,
