Home › Forums › SUSTAINABLE CONSTRUCTION, ENERGY and WATER CONSERVATION › Building and Construction › Alternatives to expanding foam stuff for gap filling?
March 29, 2013 at 4:54 pm #257701
I am in the process of turning an old tin shed into a habitable home. A friend is going to do most of the work for me, but I am researching materials etc. There are gaps in the walls and between the walls and roof, from 1-7 cms, I would say. Friend has suggested that expanding foam stuff for the gaps but I wasn’t sure about the toxicity/offgassing/ugliness of it.
What else could I use? Or does anyone know how toxic that stuff is anyway?March 30, 2013 at 1:40 am #531990
How big are the holes?
Whats the final internal finish, plaster, tin, wood?March 30, 2013 at 6:09 pm #531991
A quick look through google will indicate that most expanding foam/fillers are toxic during application, but are less so when cured. Most are flammable as well.
Most are, when dry, able to be sanded or painted (I’d wear a dust mask).
There are a couple apparently ‘eco-friendly’, but it looks like you’ll have to find and order them from OS.
You say it is a tin shed. Is it going to be clad in anything?March 30, 2013 at 6:14 pm #531992
If its a tin shed, I would use sticky aluminium flashing. Its very maleable and has a sticky coating that stick like you know what to a blanket.March 31, 2013 at 1:18 pm #531993
We live in a weatherboard and tin house that was built insulated with sisal (the foil). It is very cold in winter and very hot in summer as doesnt have much thermal mass. I would not recommend useing only foil if your hoping to live in it for any length of time. Can you insulate internally using batting (wool would be awesome but expensive) and cover that with plaster board?March 31, 2013 at 3:53 pm #531994
Or another idea is to sheath it in a strawbale skin 🙂
Depending on how much room you have around the outside.
:whistle:April 1, 2013 at 3:00 pm #531995
The inside will be insulated with wool batts, “clad” in a fine aviary wire to begin with (to hold the insulation up, and hopefully exclude mice somewhat). No solid internal cladding, because a)timeframe b)cost and c)the shed is tiny enough now I hate to take up more space with internal cladding.
The expanding foam stuff is like this http://www.bunnings.com.au/products_product_filler-expanding-foam-sika-850ml-boom-expanding-foam_P1210302.aspx?filter=categoryname–Paint+Fillers
which looks less toxic but I have no idea of the difference otherwise.
At the top of the tin walls, there is a gap maybe 5-7cm wide before the roof, all the way along the walls (was obviously not built with sealed-box qualities in mind. the floor is always covered in leaves etc that blow in from outside through the gaps 😀 ) and that is where he thought the expanding filler stuff would be handy.
i did think about strawbales for the outside 🙂 but there isn’t really the space.
It’s only small. Maybe 30-40m2? If that? In an L shape. But I have hopes that it can be turned into something cute and cosy. And hopefully non-toxic.April 1, 2013 at 3:35 pm #531996
If the gap is uniformish you could get a piece of metal bent up at a sheet metal place and put it in.
Its not that expensive or hard to do.
Just match the existing materials so you dont get electrolysis (rusting)April 2, 2013 at 12:26 pm #531997
For example, roughly the size of the structure you are talking about, is just a small 6 metre by 6 metre building with walls say 2.7 metres high. You could do away with the old sheeting with the gaps problems and replace with new. That would be 8 sheets for each side, 4 sides that’s 32 sheets and 16 sheets for the roof. A corrugated sheet covers 762 mm. Add some new gutters, flashing and vermin proof sheet metal strips around the entire bottom edge, plus fasteners. You have a perfectly sealed building from weather, wildlife and insects. No need to fuss around with patches for gaps and toxic expanding foam insulation that the wildlife eat through anyway.
At $13 per linear metre, it would cost about $1800 for new corrugated zinc sheets for the walls and roof.
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