Spray Foam Insulation

[r carl]

Avion's use of foam insulation has been brought up several times in this thread and it seems no one wants to talk about that.... Avion's are insulated good and quiet inside. Is there any problems with their use of their foam?

[kikileg]

Rockwool? Mineral wool? I used to own a stainless business and we always used a Mineral wool as it had a free chloride content of less than 25 ppm...and would therefore not affect the stainless long term. Not real familiar with aluminum...

I am about to do a reno so any advice would be appreciated.

Keith

[slowmover]

Originally Posted by StingrayL82

Streamline started using their Insul-XL aerospace urethane spray foam in 1968; our 1968 29' Empress had it. When I took the interior walls off in 2003, I was surprised to find it, because the brochure I had didn't mention it, but the 1969 brochure does. The foam was perfectly intact. There was actually about 1/4" of space between the inner wall and the insulation. I can tell you that the Empress was always warmer than our Sovereign has ever been.

Would the reason that spray foam insulation wouldn't work in the Airstream be because of its semi-monocoque construction?

That's my suspicion. Streamline and Avion had the best frames (triple 5" or 6" mains); and, along with Silver Streak a full 6" of insulation and dead air space under the floor. Complete double shell on all three if I remember correctly, where the floor is not a structural member (only indirectly); none of this "belly pan" business (why A/S needs to get back to roots of light weight and best aero, IMO; make that design work 'cause then the trade-off doesn't hurt so much).

This is a great thread, keep it coming!

[hampstead38]

We're going to find out if spray foam works. One of the appeals (for me) in using the medium density foam was noise reduction. I think the inside of the coach will be a little more quiet... which I prefer for sleepy time. I'm with Nax on the belly pan thing.

As for the foam we used, I posted the manufacturer and the technical specs. Of course, we won't really have anything major to report until we've used the coach for a few years.

[A-Merry-Can]

foam it up! I wanna see pics!

[slowmover]

Was reading some more yesterday on AVION and found this (practice prior to closed cell polyurethane):

". . The inside of the outer skin is sprayed with a rubber coat covering all seams and rivets to prevent water penetration. The spray also acts as a mastic for applying blankets of 1.25" plastic treated Fiberglas insulation. Next, an inner skin of aluminum is riveted to the rib framework leaving ample air space between the insulation and inner skin. This air space prevents any inside condensation.

In reference to the overall insulation, it appears that, then and later, AVION insulated the shell above the floor. The floor was two panels of wood with a substantial "sandwich filling" of Styrofoam. I have read that when these trailers leak (badly installed awning upper mounts) that water does get to the floor. There is at least one thread/resto blog entry out there showing how to sister-in a repair (shell off ain't gonna be happen'in). How the tanks were insulated and outer skin done -- the interplay -- isn't as clear to me though drawings make it appear straightforward.

[slowmover]

Yah, Hampstead, we WILL need pics. Be sure to get the Al Quaeda hospital gown pictured in the water treatment/filter thread on first. In camo, as befits your profile pic . . . .

[Kevin245]

Originally Posted by REDNAX

Was reading some more yesterday on AVION and found this (practice prior to closed cell polyurethane):

". . The inside of the outer skin is sprayed with a rubber coat covering all seams and rivets to prevent water penetration. The spray also acts as a mastic for applying blankets of 1.25" plastic treated Fiberglas insulation. Next, an inner skin of aluminum is riveted to the rib framework leaving ample air space between the insulation and inner skin. This air space prevents any inside condensation.

In reference to the overall insulation, it appears that, then and later, AVION insulated the shell above the floor. The floor was two panels of wood with a substantial "sandwich filling" of Styrofoam. I have read that when these trailers leak (badly installed awning upper mounts) that water does get to the floor. There is at least one thread/resto blog entry out there showing how to sister-in a repair (shell off ain't gonna be happen'in). How the tanks were insulated and outer skin done -- the interplay -- isn't as clear to me though drawings make it appear straightforward.

Our 73 Avion has spray foam in the walls and a sandwich insulated floor and yes it leaks just like our 76 Sov. However, since the wood floor and the structural ribs attach directly to the frame floor replacement/repair can be performed shell-on. Removing interior components for access is still a pain though.

The tanks sit below the sandwich floor and are not insulated.

Kevin

[slowmover]

The tanks sit below the sandwich floor and are not insulated.

Thanks. That's what wasn't clear.

(Are there any pics here or elsewhere of that '73? I'd really like to have a '72 Avion, but am growing more fond of '73-'76).

[markdoane]

Originally Posted by REDNAX

The tanks sit below the sandwich floor and are not insulated.

Thanks. That's what wasn't clear.

(Are there any pics here or elsewhere of that '73? I'd really like to have a '72 Avion, but am growing more fond of '73-'76).

What is clear is that this is your 1000th post on the Airforums!

Which has now been documented for posterity. Congrats.

[boatdoc]

Originally Posted by hampstead38

We're going to find out if spray foam works. One of the appeals (for me) in using the medium density foam was noise reduction. I think the inside of the coach will be a little more quiet... which I prefer for sleepy time. I'm with Nax on the belly pan thing.

As for the foam we used, I posted the manufacturer and the technical specs. Of course, we won't really have anything major to report until we've used the coach for a few years.

Hi hampstead38;
I hate to beat posts with hundreds of different opinions. What I like to tell you is this; I have worked over 40 years with mix and pour closed cell urethane foam, otherwise known as rigid closed cell foam. The rule #1 is that it should be installed only in places which will not flex any more than temperature related expansion and contraction. Seven and even 10 points in R value does not justify the expense. The walls are 2" inside and you need room for wiring and other stuff. Secondly, Airstream flexes under towing condition. Hence this is why it is riveted and not welded. Welds would crack and the more times you weld aluminum the more brittle it becomes. With time as the trailer flexes foam will fatigue and fragment creating a microscopic dust which is extremely hazardous to your health.
This dust will eventually find a way into the interior where it will be carried by moving air with help of your furnace, AC or fan. While the rigid foam has insulating quality it is mainly used as structural component by it's rigid quality pending it's weight per cubic foot. The heavier it is, the more rigid it is. The lighter weights are used as flotation in boats and in many structural components.

My question is this; Why would anyone go through the expense and effort to install a rigid foam in the Airstream? Bubble foils are easy to install and are higher in R factor. If you spend equal amount of money as you spend on contract of installing a rigid foam, you can almost buy aircraft quality insulation. Even the inexpensive bubble foils in 1/2" thickness can give 12+ R factor if properly installed. I am truly sorry for getting involved in this post again as I have already voiced my opinion based on my experience with rigid foam in Airstream. I did not intended to fire up anyone therefore I will refrain from any further arguments. My point is; Before jumping into something with both feet, do your research. With the wealth of information available on the INTERNET which is mind boggling and it is free. I hate to see mistakes being made while good sources of information are available. Thanks, "Boatdoc"

[ticki2]

Boatdoc
Could you please give us the name and type insulation that yields an R factor of 12+ in only 1/2" thickness ? Thanks

[Wabbiteer]

He is speaking of the reflective foil types installed in a favorable orientation with the correct 'dead air' spaces. Up to R-14+ in certain circumstances, such as bouncing heat upwards by helping it do what it naturally wants to do - rise. Where that rating drops is holding heat down, or cold up and it falls back to R-6 or less.

Non bubble "foil-foam-foil" was my choice...

[boatdoc]

Originally Posted by ticki2

Boatdoc
Could you please give us the name and type insulation that yields an R factor of 12+ in only 1/2" thickness ? Thanks

Hi ticky2
As Wabbiteer has said One of them is reflectix. Walls do not absorb as much heat as the roof. I have done my Argosy with back to back two layers. One reflects heat away the other keeps heat in. With 15.000 BTU low profile Carrier my trailer becomes a refrigerator in 95 degree heat with direct sun. It is nice and overly toasty in cold temps. Walls had urethane foam 5/8" strips glued onto outer skin. Reflectix was cut oversize and cut edges of each panel were glued with 3M 5200 onto the ribs. After the adhesive set up pre-cut edges were trimmed to 1/16" past the rib. This way the inner skins sealed the cut edges by compressing them during installation. One important note; you must provide some exit holes in the bottom channel to drain any possible condensation. My floor is a 5/8" aluminum clad on both sides plywood. I have drilled four 1/4" holes per side in the attaching to the floor channel at even distances. Into the holes a aluminum tubing was driven in to seal the plywood. I do not camp in below 0 temps therefore it is more than sufficient for me. We ran a test last late Fall at 34 degree temp. Our furnace kicked in for 7 minutes every 160 minutes. That may not be good enough for some folks, but I think it turned out great. Most times we keep the kitchen window cracked open an inch to eliviate the condensation inside. Thanks, "Boatdoc"

[hampstead38]

I appreciate the advice, Boatdoc, but the deal is done. The spray foam is in. As for air quality, maybe I'm a bit fatalistic having grown up in Libby, Montana, ground zero for vermiculite.

We chose the foam for a number of reasons. It has good insulating qualities. It should reduce noise from outside the coach. I spoke with one of the engineers at Icynene about the product. He felt it was appropriate for a mobile environment where shock and vibration issues were present. Honestly, I couldn't find any information that suggested outgassing or particulant issues. I'm not disagreeing with you, but I did do my homework before we pulled the trigger. I'm also not opposed to putting a small HEPA air filtration unit.

[A-Merry-Can]

pics!!!

[ticki2]

Boatdoc and Wabbeteer , i appreciate the response but I did ask a very specific question that did not get answered . I have been a builder for 40 years and know of no such product . Still always willing to learn.

[boatdoc]

Originally Posted by ticki2

Boatdoc and Wabbeteer , i appreciate the response but I did ask a very specific question that did not get answered . I have been a builder for 40 years and know of no such product . Still always willing to learn.

Hi ticky; Sorry that I have misunderstood your question but at times mind does not follow the print. Here is the scoop;

R-Values is not the only factor to consider [sorry Wabbiteer]. Simply putting it the technique of installation can reduce R-Value in half. It is important to consider reflective and conductive R-Values of insulation. Any polyurethane spray foam offers only R-Value of 6.3 per 1" of thickness.
With 1.5" of available wall depth you are under R-10 Value. It must be said here that conductive transfer is excellent, however it comes short in reflective properties. See www.pasprayfoam.com. Fiberglass insulation offers very little in Conductive properties as the air flow is not restricted unless the vapor barrier is sealed well and not perforated by items such as wires fittings of all sort, etc. In order to achieve maximum R-Value one must look at both factors.

The ease of installation of bubble foils makes sense. It can offer you great reflectivity as well as conductive transfer barrier. One of products is Refleticx. There is other products of quality such as FarmTex and "Foil double bubble foil" from Texfoil. Most of them are 97 percent reflective and with only 0.03 emissivity, 100% vapor barrier, resists mildew, fungus insects and rodents and it has Class/AClass fire rating.
First you must understand conditions to which your Airstream will be exposed to. Climate in which you will do most of your camping should dictate different approach to your needs. If you camp in 120 degree
temperatures you will need to have reflectivity on both sides of your foil.
Most bubble Foils are reflective on one side. The curved area of the roof should receive back to back foil to keep heat out and in. The wall in most application may need only one layer, but attention needs to be paid to stopping Conductive Transfer from the roof area into walls. It can be done by providing a separating vapor barrier between the two spaces. Also, be sure to provide a air space on both sides of the foil which adds a bit to R-Value. This can be done by gluing strips of rigid foam on the inside of the outer roof and wall skins and gluing in a stretched bubble foil to maintain an air space rather than placing it on the skins. Provide enough excess to wrap the foil along the ribs to minimize area of Conductive Transfer. Be sure all edges are sealed. Work requires lot of measuring and fitting but it is fun. No need to outsource the labor unless you do not have time to DIY. I hope this clarifies the point. Thanks, "Boatdoc"

[Gene]

Boatdoc,

I have used Reflectix on some windows and skylight and both sides look the same to me. If I understand your posts, they are not and that's why you double it. I don't understand.

By putting it on all the bedroom windows, it has moderated temps a bit even though it doesn't seal as well as putting it in walls.

Gene

[Kevin245]

Originally Posted by REDNAX

Are there any pics here or elsewhere of that '73? I'd really like to have a '72 Avion, but am growing more fond of '73-'76.

Here are a couple from the 2009 Fall Vintage Rally. Nothing up close though.
Ours is a 73 Travelcader. 25 footer with a center double bed and a factory convertible fold down bunk.