Airstream renovation
Hi, I’m helping someone renovate an airstream, which is to be a non moveable, room near their house. The house is in upstate NY, on the border between zone 5a and 6a. It’s completely gutted, so it’s just an aluminum can at this point. The plan is insulate it with closed cell foam, 1-1 1/2″ on walls and ceiling, 3″ in floor. That’s all the insulation the frame will allow, unless some more extensive modifications are done. It’s going to be heated in winter with a small propane heater, designed for boats. The interior finish is still being decided, but the owner is leaning towards wood, which would match the interior of the house. I’m wondering about condensation in this situation, and where the dew point would be, but I don’t know how to figure that out. I don’t want the wood, if that’s what we use, to become moist, develop mold, etc. The airstream is 27’6″ x 7’6″ x 6’8″. It has about 60 sq ft of windows in it.
Would appreciate any help
Thanks,
Mark
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Replies
Here's a photo of the gutted airstream
Do you think you'll be comfortable in a trailer insulated to somewhere below R-8?
The idea is to used closed cell spray foam, which should make it a pretty air tight can, so it shouldn't take much to heat it since it's a small space. Also, it's not going to be used all the time, but more as an outdoor hangout for a young boy.
I have no experience with such work, however, the wall and floor skeleton would not be insulated and it would have some serious thermal bridging. I would try to get an extra inch or two and get more CC insulation. Also, I would think a propane heater is bad for air quality; since is such small space, I would think on a small electric heater and maybe combo AC unit if they have humid summers.
You can make a pretty-airtight space out of a plastic garbage bag, but that doesn't mean the bag is well-insulated. So, to amend the question: Do you think the young boy will be comfortable in a trailer insulated to somewhere below R-8?
For the record, I think it's a neat idea, even if most building inspectors wouldn't.
MD, there are millions of people that are comfortable in their uninsulated brick and frame homes, so the answer is yes, the boy would be comfortable in a heated, R8 trailer.
With the heat on, R8 is enough to prevent condensation in most conditions, if breathing is the only source of water, (no cooking). The single glazed windows will sweat and freeze up, though.
99% of all RVs and trailers and boats use propane heaters, so I don't see a problem there either. An air to air heat pump should be cheaper at today's rates.
Kevin, yes, breathing would be the only source of water. There's no plumbing, kitchen, bath, etc. and the propane heater is one designed for boats.
I agree with you that it should be comfortable in there. It's a trailer that's been used for years as portable living quarters, and it's going to be insulated much better than it originally was. It's just that an aluminum can is a different sort of envelope than I'm used to, and I don't want to create an environment that is a problem for wood, if that's what the finish material will be.
I renovated a 1956 Airstream and also have a marine stove, mine is from Dickerson. If the airstream is on a fixed base then why not consider using spray foam under the floor as well. The comment about thermal bridging is funny, of course there will be bridges it's all aluminum and there really is no method to avoid bridging or use good windows. Do your best, there is no one best answer. We used tekfoil and then pink insulation which was then covered with a new aluminum skin. The dickerson heaters do a nice job of keeping the interior nice and warm, but you might want to include an under floor electric radiant mat towards the rear to supplement during really cold days.
If your airstream will never see the road again, using spray foam is fine. If you ever want to use on the road again, I would not use the product as there is a fair amount of movement/flexing of the shell. Ridgid foam will turn to dust over time.
HTH
Doug, the marine stove we're going to use is from that same company.
The airstream is definitely never going to see the road again, so I thought closed cell spray foam made the most sense, due to the limited amount of space there is and also for making an airtight enclosure.
What did you use for the interior finish? and in particular, how did you deal with those compound curves?
We used new sheet metal ordered from an aircraft supplier and used the old sheet metal as templates. The internal end caps on ours were the original 13 panel aluminum, which we stripped and polished. The shell of yours looks like a late 70s, early 80s which probably had a composite end cap. I would keep that on hand if you haven't already thrown it out. It could be helpful to make a template out of.
I have seen end caps crafted from Baltic Birch plywood (bendy stuff). I used the product to make curved cabinets for our renovation. Make sure to get Baltic birch since it is design to bend easily in one directly, regular birth ply will not bend. Good luck crafting one, I have only seen a couple successful creations.
There are a couple artists on the net that are worth referencing on how they skinned the interior using birch plywood. vintagetrailering.com is one, Dave is amazing. There are others on airforums.com, http://www.airforums.com/forums/f321/1962-22-safari-15592.html is a great thread I looked at loads.
As for air tightness and insulation, make sure to block up all little holes with metal that is caulked and riveted. Even closed cell foam will attract mice if they can get to it from underneath. Most older airstreams have had mice at one time or another, doesn't hurt to give it a good power wash on the interior with a little detergent.
HTH
Thanks, Doug. Those look like some great links!
Here's a link and a pic of an old FEMA trailer that was refurbed to be a sustainable artist's den-type thing. I thought it was the coolest thing I'd seen for a long time. I know it's not an Airstream, but neat anyway.
http://www.emergencyresponsestudio.org/
This is another cool project along the same lines: http://www.winkarch.com/project.php?id=65.
David and Michael, thanks , those links are interesting. Trailers and in particular Airstreams seem to bring out the creativity in people. Right now, I'm trying to figure out how to insulate this one for Northeast temperatures in a low VOC, IAQ friendly kinda way.