Foams in general are not a good practice in architecture in most (if not all) applications...especially natural building, in my view of the topic.
I find it amusing (not really) that everyone that claims "environmentally safe" are either installers, manufactures or folks that are already invested in living in one of these "plastic houses," (until they can't take the smell or other issues.)
Always read your MSDS (if you can find and interpret the silly things.) Do these chemicals sound like something you want to live wrapped all around you...??
Polymethylene polyphenyl isocyanate
4,4'Methylene bisphenyl isocyanate
There are many articals both for and against foams...here is just one...
Manufacturer Faces Class Action Lawsuit
Dale Hodgins wrote:
Results were as variable as those doing the work were.
That is the truth.
There are places I would use spray foam, but it has to be done right and with compatible materials. Under the floor of a tiny house sounds like a good use, but does it trap moisture to rot wood and rust metal?
Tiny houses need to be extra careful about offgassing and air quality, there just isn't enough volume to dilute any problems. They also need to minimize wall thickness so most natural materials have a real problem fitting.
Are you worried about heating or cooling? The other design details (windows and doors, primarily, but also thermal bridging) and how you park it (shade and wind protection) have a much bigger influence on heating and cooling than insulation A vs B.
R Scott wrote:but does it trap moisture to rot wood and rust metal?
Yep...very badly in my experience, and one of the reasons I have stopped using it completely and returned to "packed oakum" or related methods...
In some very rare locations do I find or think it may be viable...but those areas too I think could have a more "natural method" used to just as good long term performance...
R Scott wrote:Tiny houses need to be extra careful about off gassing and air quality, there just isn't enough volume to dilute any problems. They also need to minimize wall thickness so most natural materials have a real problem fitting
Exactly and very much part of this equation...
Angelika Maier wrote:Why not the simple cheap yellow or pink bats? They are better for your health and do insulate better too. Because the foam is rigid and as the timber moves it will give you cavities were the cold gets through.
It's been my experience and findings in the research I have done that "spun glass" insulations of all types are an overly "hyped" product with many unfounded manufacture claims and very subjective application results.
All forms are highly prone to "air infiltration," wipes out its performance efficiency.
It loses its R value the colder it gets outside.
It goes to zero R value if expose to moisture and if the humidity is above 60% the same effect takes place...lowered or no R value. This renders it a "nonviable insulation" in my experience....which both these conditions can take place in the interstitial voids of walls...
I do not have experience with ALL SPRAY FOAM.
I have some exeriences with Rigid Foam insulation and ROXUL insulation.
We have access to FREE rigid foam insulation because a company which makes SIPS Stuctural Insulated Panels gives away
what they do not use, sometimes pieces are 4x8 or longer, sometimes smaller.
I fitted this into our space and used canned spray foam inbetween to create what some people call
Poor Man's Spray Foam...
This rigid foam is R-4 per inch and some pieces were 5 and a half inches, some 7 and a half, some 4 inches thick.
I put this insulation into my 220 sq ft. tiny living space which is part of a mobile home. It created a much warmer space which I am able to
heat with a small Delonghi radiant oil space heater.
I first put in Arma Foil Radiant Barrier with 2x2s between the exterior walls and the insulation to create a dead air space.
THen I added the rigid foam in some areas and ROXUL insuation in others.
I did this on the interior of the rooms, rather than try to put it into the already poorly insulated mobile home walls.
AND IT WORKS GREAT.
ROXUL insulation is made from STONE.
It is water resistant, pest resistant and fire resistant, and does not grow molds.
IT can be cut with a serrated knife. It compresses into place.
Quoted from ROXUL's site:
ROXUL’s line of fire-resistant insulation for residential use includes both thermal and soundproofing products: ROXUL COMFORTBATT® and ROXUL SAFE’n’SOUND®
The advantages of ROXUL make your insulation choice easy.
ROXUL insulation goes beyond what most conventional insulations offer. The main ingredient of ROXUL insulation is stone. As a result, it provides some very distinct advantages:
Delays the spread of fire, providing you and your family with precious extra minutes to escape.
Won't burn, or release toxic gases or smoke when exposed to high heat.
Withstands temperatures of up to 2150˚F (1177˚C) – well above heat levels of typical house fires.
After exposure to water and moisture, won't slump in the wall cavity like many conventional batt insulation products and R-value will not be affected.
Inert substance that does not support mold or fungal growth; resulting in a safer indoor environment for your home.
Made from Stone:
Created from a unique combination of stone and recycled slag – a by-product of steel production that would otherwise go to landfill.
Non-directional fiber structure and higher density for better dimensional stability and an effective barrier against noise.
Easy to Install:
Easy to cut precisely with a serrated blade, such as a bread knife.
Non-directional fiber of ROXUL stone wool helps absorb acoustic waves and can reduce the intensity and propagation of noise.
Effectively reduces airflow and sound transmissions.
Higher air flow resistivity means better sound attenuation.
Jimmy Catlin wrote:I am in the design phase of a tiny house build and exploring insulation options. I can not find a consistent reliable answer as to whether or not icynene spray foam is a safe product. Any insight from people with more knowledge and experience with this product would be greatly appreciated.
Safe in what way? What will happen to it at the end of the life of the tiny home? What ecosystem are you expecting to deal with this product when it eventually becomes waste? I'm betting there are safety issues with manufacture too (and disposal of containers, applicators etc, as well as waste at the factory).
We have other options for insulation that create far less problems from a permaculture perspective.