Multi-layered bubblewrap (non-foil type) as replacement for rigid foam? Or other ideas??
I am building a house in Japan and have not been able to source affordable rigid-foam panels. The house is a timber frame with a surround of DIY “SIPS” (non-structural) in which I want to sandwich 120mm or 4.7inches of rigid foam (R30). I am nearing the point where I am about to import Celotex panels from the UK (http://www.celotex.co.uk/products/celotex-products/celotex-xr4000), which are cost effective (even inc. shipping) compared to domestic products.
For ecological reasons, however, I really don’t want to have to import “air” (these panels fill an entire container load), and was wondering if anyone here could suggest an alternative? One idea I had was common (non-foil) packing bubble wrap which could be folded 20 (or more) times over itself (up to 120mm). This would be around half the cost of the UK panels, and perhaps would give me a similar R-value? Any thoughts?? Is this a crazy idea?
Another idea would be to fill the sandwich with rice husks, but I think 120mm (4.7′) would not get me as much R-value…
Any help greatly appreciated!
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Replies
I believe if you search here for bubble wrap you'll get your answer. I don't recall much + said about it, but that could be just my brain. Buildingscience.com is another good place to look. Wouldn't you be feeding bugs and rodents w/ rice husks in your walls? Good luck, whatever you decide.
Bruce,
Bubble wrap has a very low R-value, so I don't suggest you go the bubble-wrap route.
Almost any insulation product would be better than your two suggestions -- bubble wrap or rice husks. Japan is an advanced industrial nation, and I find it hard to believe that insulation is unavailable in Japan. You need to find out what types of insulation are commonly used in Japan, and choose an available local product.
Thanks for the responses. Japan does have great products but anything that is not conventional (glass/rock wool etc.) is 2x or 3x the cost of the European equivalent. This is especially true as the thickness decreases and the r-value increases. Largish house means it is at least half the cost to import good rigid panels... Spent A LOT of time researching (I read Japanese and have connections here to builders and architects) but it looks as though I'll be sending a container load of "air" across the oceans :(
Bruce,
If you have considered building wall panels that you were willing to fill with rice husks, why not build wall panels and fill them with Japanese insulation? Rock wool is good insulation as long as you install it carefully and pay attention to airtight construction details.
Thank you again, Martin. Yes, I looked at this. Trouble is that the cost/performance balances so that R16 Japanese rock wool= R38 European rigid foam. As you go up in Japanese R-values the cost just increases and makes the import better and better value... Real shame...