Rigid foam insulation

Junk Man · 06-02-2003, 08:17 AM

For those of you building your own, what are you using for insulation? I would like to use rigid foam insulation (beadboard?) if possible, since it is easy to work with and does not settle. It can be cut with a table saw so it will fit tight between the frame, and comes in many different thicknesses. The main downside is that it doesn't have a very high R value, and I wonder if it will sqeek while going down the road.

I have also thought about the other foil faced foam (possibly made by Firestone?), which has a much higher R value, but is also much more expensive. Again, I wonder if it will squeek. Does anyone have any eperience with either of these?

I would sure hate to build the darn thing and then have it sqeek like crazy and have to tear it apart and change the insulation.

Jeff in South Dakota
1995 Ford F-250 4X4 PSD
1992 Skamper Slide in camper
1984 Holiday Rambler 5er
1979 Mercedes Benz Unimog

geof · 06-02-2003, 05:10 PM

I use a polyisocynate foam board with aluminum foil on each side[R-max]...it's $10.00 per sheet[4X8' at 1.5 inches thick with a "R" value of 15....cut it with a razor knife-box knife or carpet blade....score and fold then cut the backing just like drywall....glue in with liquid nail and hold in place with carton tape till the next day....foam fill gaps with spray can foam....it won't squeek. Make sure you cover it with a fire resistant finish such as alminum or maybe a flame resistant panel....finished, it's overkill but you will be more confortable-and won't need so much heat/cool....If you can't get 1.5 inch use two sheets: one 1'' and the other 1/2 '' or two 3/4"....ask store for a discount on janged sheets that are busted snagged....I saved at least 50% that way....The better the job foaming you do, the better the insulation in your coach....some reefer trailers are spray-foamed with polyisocynate....thats the best way to do it...costs about $1.00 per sq ft per inch thickness it's "R" value is 10+ per inch thickness because of no air movement what-so-ever any foam will not decay-shift-settle if it is covered and the sun can't shine on it....heat won't bother it if there is a radiant barrier....geof

Jim Gehlen · 06-02-2003, 08:16 PM

Jeff: Nothing to do with insulation but, we are now at Angostura, Cheyenne campground. If you get to this area, look for the us on your way to the reservoir. Little red truck is visible from the access road. E-mail me at jgehlen538@aol.com and I'll send you the phone #.

geof · 06-02-2003, 09:36 PM

Jim:....there's no way I'm getting away this summer for more than 3 days....I am in the middle of selling my warehouse!...[HOO-RAY]... once that is done, I might have time to travel but, that looks like this fall-at the earliest....at this point...enjoy your stay in Cheye-town....wish I was there...geof<in rainey Cincinnati in a leaking warehouse...OY!...>

Junk Man · 06-03-2003, 06:18 PM

Jim,

I was wondering if you were there yet, figured you were. Came through Hot Springs a couple of weeks ago on the way back from Zion NP and Las Vegas, but was anxious to get home, so didn't swing down to the lake.

I want to get down there and see your rig, but am pretty busy this week, and leave for an Alaskan cruise next saturday. I might have to try to sneek a fishing trip in before I leave if possible. How long will you be there?

Jeff in South Dakota
1995 Ford F-250 4X4 PSD
1992 Skamper Slide in camper
1984 Holiday Rambler 5er
1979 Mercedes Benz Unimog

Junk Man · 06-03-2003, 06:26 PM

Geof,

The polyisocynate foam board is the other foam I was thinking of (I think). I don't know if I have seen it in 1 1/2 thick sheets, seems like it is usually 3/4 in thick. Will have to ask next time I stop at the lumber yard.

I was also wondering if the steel framing would transfer the heat (or cold) very much. When framing with wood, there is a thermal break, but on the truck box, the framing will be steel tubing, with OSB or plywood fastened inside, then the finish paneling attached to that. Will that be enough of a thermal break? This is how Showhauler builds thiers as near as I can tell, so I suppose it must work.

Jeff in South Dakota
1995 Ford F-250 4X4 PSD
1992 Skamper Slide in camper
1984 Holiday Rambler 5er
1979 Mercedes Benz Unimog

Jim Gehlen · 06-03-2003, 08:15 PM

Jeff: as it stands right now, September 5.

geof · 06-03-2003, 11:15 PM

Jeff-Showhauler uses a aluminized bubble wrap material....a neighbor that works for our local uility, that is an engineer working on insulation/heat/cold transfer problems, told me that it didn't have a very long life because of abrasion inside a cavity on a moving vehicle....and it was his opinion that polyisocynate was the way to go-best sprayed on. If not, that glued in place and the gaps filled with spray can foam was the way to go....that is how I have re-done my Airstream....I'm assuming you are talking about filling the hat chanels or the tubing...to increase the "R" value....I would if I was doing the retro....but them again I don't have a big labor expense as I use my office worker to do this work-as she needs income[cash] because she is a single mom. I guess the best way to go is fill the cavitys-the hat channels and insulate the face before applying the interior material.... therefore minimizing the transfer which would be only through the fasteners....what do you other guys think?....I can ask my neighbor about what you describe within 2 days....He has been a tremendous source of knowledge and experience as I have a super-insulated house so heat and cooling costs are cheap....geof

Junk Man · 06-04-2003, 08:23 AM

Jim,

Sounds good, I'm sure that I can make it down there before then.

Geoff,

I plan to frame it with box tubing, so it would not be easy to fill the tubing with foam, unless I drilled several holes in each section, and sprayed foam in. I don't think that filling the tubes with foam would make enough of a difference to juustify the trouble (but I could be wrong). If I was using a C channel instead of a tube, I think I would try to fill them.

I don't plan to spend much time in extreme weather conditions (at least not if I can help it), so the insulation is not going to be real critical, as long as I have enough for normal conditions.

The reason I ask about heat transfer through the steel framing, is that I had a converted school bus in the past, and although there was insulation in the cieling, the heat (or cold) still transferred through it quite easily. Of course, it had a steel headliner, which didn't help. If I changed it to wood, it probably would have made a big difference. Because the headroom was limited in it to begin with, I didn't bother.

On a hot day, one A/C unit would barely cool half of the bus, where I can cool all of my 34' fifth wheel with one A/C unit. Of course, the 5er has less windows, and also is better insulated under the floor.

Jeff in South Dakota
1995 Ford F-250 4X4 PSD
1992 Skamper Slide in camper
1984 Holiday Rambler 5er
1979 Mercedes Benz Unimog

geof · 06-04-2003, 08:36 PM

The A/C issue is the most critical as heat is instant and there are several alternatives for space heating-electric radiant-recirulating hot water-electric blanket-fireplaces and now I understand heat pumps....which is A/C in reverse down to what?...50 degrees?....There are NO 4 season trailers made to my knowledge [because of lack of insulation]....and most salespersons say the same thing....though some have an upgrade insulation package....which might be an advantage...I'd have to have it looked at. There are some things that a person can do the upgrade existing insulation-which takes some planning and a little money which will make a big differance in the HVAC issue. I'd rather build it correctly than retro it later....I've done my house over the last few years and I'm tired of drywall dust etc-buts it's done now so I'm expermenting on/with the Airstream currently....geof

You may also like: