Hey all, I know that this horse has been beaten to near death but... for the cause of science I thought that I would throw out another INSULATION idea for your consideration: Quick curing two-component spray polyurethane foam insulation.
It's the stuff that you've seen used on PBS's This Old House. They spray it into the open stud bays where it sticks and immediatly begins to expand. Usually they spray it on thick enough where it expands beyond the face of the studs and is then cut off flush to the wall surface. In an older home renovation the benefit is that it seals the walls and acts as a moisture "resistant" barrier. I may use it on the house we are about to purchase, a century home with plaster walls and no insulation. The foam can be sprayed (or poured ?) through small holes into the wall cavity where it rises and fills it up providing R-7 per inch of wall thickness.
On an Airstream perhaps spraying 1 inch thick into the open wall and then adding foil would be a good use? It's not cheap but it will provide another layer agains water penetration, provide more soundproofing, it's non-offgassing, and mold doesn't like it
Also could an ideal use be for insulating under the floor?
This is the only DIY distributor I've found so far. Good web site with lots of tech info and FAQs answered.
Hey all, I know that this horse has been beaten to near death but... for the cause of science I thought that I would throw out another INSULATION idea for your consideration: Quick curing two-component spray polyurethane foam insulation.
!
Steve
Houses don't move. Trailers and motorhomes do.
The twisting of the shell or body, in time, will grind the spray on foam insulation to a powder.
Airstream tried in in the doors of the early 69 models.
I've use the spray foam to help "mouse proof". I used it to fill lots of nooks and cranies. I read somewhere else they will knaw through it.??? the jury is out but so far no mice. "I hate those meces to pieces"----pieman
Let that horse die. the 1/4" foil bubble is the new horse
Quote:
Originally Posted by Inland RV Center, In
...Airstream tried in in the doors of the early 69 models. It was an absolute failure....
I'm not shot down that easily...recall this is for the cause of science. Also, I bet the technology has changed maybe a tad in the last 40 years. I remember that old foam would turn to dust with age even without abuse. I plan to set up some tests when I order the product next summer.
Steve
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I recently had an estimate to insulate the house with foam, while he was there I asked about Chummy. This product goes in with existing Fiberglas insulation and expands around it to fill the cavity. The installer said it would work and would guarantee the product not to break down. However, the cost was three times what regular blown insulation would be for the house and he did not give me a price for Chummy.
One downside to spray in place foam is that in the event of any damage(dents etc), it makes removal and repair much more labour intensive.
As for vapour barrier the glue laminations in the plywood floor are an effective barrier by themselves.
Also if any condensation or other moisture was to find its way between foam and adjacent surface it would not escape easily.
I have a related question for those who have had their belly pans off.
Is the fiberglass insulation fastened up to the underside of the floor ply or does it rest on the belly pan?
Al
I used that foam in a can on engine hood for Suburban.
The two metal sheets had separated making a tin can sound and a 'ding' when the hood was closed.
After adding foam it is solid unit.
Slams shut with a very nice thud.
Did this 5 years ago..zero grinding and is still holding panels tightly together.
I'm reluctant to add fuel to this fire, but in the interest of science, I feel I need to add some additional considerations. When I was an active architect, I seem to remember something about urethane foam insulation posing two problems. First, if my memory serves me correctly, it off gasses urea formaldehyde for some time after placement. Some people are very sensitive to formaldehyde, causing nausea and vomiting. Second, in the event of a fire, it can give off fosgene gas and other toxic gases which can be deadly. Also, it can add fuel to a fire, which fiberglass insulation does not do. For commercial buildings, it is almost impossible to achieve required fire safety ratings for assemblies using urethane foam. That said, there are expanding foam urethanes as comes in those cans you see at Home Depot. These tend to be fairly flexible and contribute no structural strength.
Then there are expanding structural urethane foams as can be found here: Fiberglass , Epoxy , Composites, Carbon Fiber - U.S. Composites, Inc. These are they types of urethane foam used in surfboards and such. They come in different densities, are closed cell so they don't absorb water, and would be very much up to the task of making a door rigid. Airstream may or may not have used their best and brightest engineers on that experiment. The urethane I've been using on windsurf boards would have made those doors rigid, light, and ding resistant. One of the upsides of urethane foam is it acts like a glue, bonding to most materials.
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I have a related question for those who have had their belly pans off.
Is the fiberglass insulation fastened up to the underside of the floor ply or does it rest on the belly pan?
Al
In my 1975 and 1980...both There is a 3" layer that is paper faced that is laid in place from above the frame, then there is a layer of unfaced that was apparently laid in place prior to the belly skins being installed. If you have ever seen pictures of the Airstream plant, they install the floor on the frame first, then flip the chassis over and install the belly pan...at least that is the way they used to do it.
Aaron
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This is for informational purposes only . I have a 12'x8' military enclosed trailer that I converted into a construction trailer. The walls ,floor and ceiling (roof) are all aluminum with 2" of foam(I think urethane) sandwiched between the inner and outer aluminum . The frame is aluminum I channel. This trailer was ment to travel on the ruffest of terrain . During the conversion I have taken some of the panels apart and there was no break down of the foam . This trailer was made in 1959 . I would think from this observation that the technology for the proper foam exists.
...it off gasses urea formaldehyde for some time after placement.... For commercial buildings, it is almost impossible to achieve required fire safety ratings for assemblies using urethane foam.
TIGER FOAM Insulation has NEVER contained Octa or Penta BDE's or VOCs, CFCs or Formaldehyde. We have, from the beginning, used ONLY the safest and most environmentally friendly fire retardants.
I think that "GREEN" building technologies have come a long way. I am sensitive to chemicals so avoid them at all costs.
Yes, It's expensive but in an older house there is no other way to provide the moisure barrier short of removing the interior walls, or the exterior clapboards. I'm estimating that I will be able to do nearly the whole house myself for the cost the installer quoted for just the attic....which is still 3 times the cost of blown insulation. BTW, the technical literature claims that the open cell foam will allow the movement of moisture through it, much like Tyvek house wrap does.
Thanks to all for keeping this discussion alive. It is certainly worth exploring even if it's not ideal for every application.
Steve
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It’s obvious that there has been tremendous technological advancement in components and methods since then.
Giant intercity buses, now made of composite materials instead of aluminum, have foam sandwich insulation.
Many advanced motorhomes made in Germany also use similar materials and techniques.
Wiltsie Truck Body, were some of my Argosy renovation takes place, uses sprayed-in foam in trailer building all the time. Wiltsie is a 55 year-old family company that knows what it’s doing.
The difficulty of spraying foam in place in an Airstream or Argosy is, I think, that the ribs in the trailer run both vertically and horizontally.
At Wiltsie, they spray the foam in place between the ribs, level and carve off any excess, and then apply the interior skin.
I didn’t use spray insulation but I wish now that I had.
Some people have mentioned the wiring harnesses, suggesting foam would make later servicing difficult. I think that is of small concern, when judged against how superior a foam insulating job can be.
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There is a 3" layer that is paper faced that is laid in place from above the frame, then there is a layer of unfaced that was apparently laid in place prior to the belly skins being installed. If you have ever seen pictures of the Airstream plant, they install the floor on the frame first, then flip the chassis over and install the belly pan...at least that is the way they used to do it.
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