Spray foam underbelly

Nursejoe · February 2021

Has anyone spray foamed their trailers underbelly? Would doing so get you a 4 season trailer? I am a traveling ER nurse and am considering buying a Tab 320 Boondock to travel with. I need you be able to travel year round. Any other suggestions would be appreciated.

AirBoss · February 2021

Aside from the issue of permanently encasing a variety of electrical and plumbing components (if I understand your intent), you'd still have to deal with keeping your black and grey tank gate valve assemblies from freezing, as we as your city water connection. Likely a type of heat tape but that also requires a trustworthy source of power to keep that tape warm. Not to mention the issue of expansion of the foam and how it may displace components. It's one thing if a rig is design-built for this type of thing. It's another to retrofit it. I don't know about the Nautilus system on the new T@B's but suspect they are not 4-season approved either. I could be wrong.

I believe there are some folks on here who have taken some steps to "winter-proof" their T@B's. Perhaps they'll chime in to share their thoughts.

Not to drive you away from T@B but there are several manufacturers who produce 4-season rigs...or so they claim.

Nursejoe · February 2021

Thank you for the response. The only other "small" trailer that I have found that is "4 season" from the factory is the Airstream Basecamp. Didn't want to spend 40k but might need to do so. Again thanks

VictoriaP · February 2021

@Nursejoe Lance & Winnebago both make 4 season trailers.

That said, a travel nurse friend spent a particularly snowy winter in Klamath Falls OR two years ago in a non 4 season Winnie. She skirted the undercarriage and put a small heater under there for the tanks and pipes, and used a heated water supply hose. There are ways to handle the problem in moderate winter climates that don’t involve potential issues with repairs down the road the way spray foam could.

bergger · February 2021

You may also want to look at Big Foot Trailers and Escape Trailers. They appear to have options to make them true 4 season trailers, to include spray foam and heat pads on the tanks. Both offer a small trailer as well. My next trailer may be one of those two brands.

DougH · February 2021

@Nursejoe Hi, I'm one of the many folks on the forum who put heat cable on the fresh water lines and waste tank pipes and gates, and heating pads on the gray and fresh tanks. If at a campsite with electric, I can flip everything on and keep things thawed down to 15-20F. But if I hit the highway without winterizing, even with the heaters on, I can't manage as well. Of course that's true of all travel trailers unless you [1] do something shady like run the propane when on the road, [2] get an oversized alternator so you can power all the supplemental heating circuits, or [3] get LOTS of solar. Only vans, some truck campers, class B, B+, C, and motorhome RVs can be true 4 season while traveling.

However, while better insulation and heating circuits help the 320, the T@B is not very airtight, and the walls are not that well insulated for winter park long term life (1" block foam and Azdel). That and the default hydronic heater is not really that powerful and will need supplemental heaters below 10F. Trailers that others have mentioned... many models from Lance, Oliver, Bigfoot or Northwood, are probably a better starting point if you'll be supporting several colder locations. Of course this week shows any state can suddenly have sub-zero conditions.

As you know, the phrases "Four Season", "Arctic Package", or similar terms are just vague industry selling jargons... not any kind of enforceable standard. In general the lighter weight or less expensive the trailer, the thinner the walls and the more likely the windows will be single pane. You can find some Forest Rivers like the Ibex series that have heated tanks and enclosed gate valves, but no heat on the piping. Step up to a Grand Design model and there's usually some insulation in the basement, some simple reflective sheeting, thicker walls and at least a heat duct or two running into the basement. Step up to the Lance (not the thickest walls on many models) and there's more formal targeted heat ducting in the basement to protect everything as long as the furnace is running. Go up to a Northwood Nash, Arctic Fox or even heavier model, and there are up to 5" thick walls with some of the highest R values on walls and ceiling. But so heavy you need a 3/4 or 1 ton truck to pull it, so fuel mileage will be horrid.

Most of the Airstreams do have heated tanks, but many have single pane windows, and most only have 2" of insulation. They're beautiful, but most models are described by their owners as 3 season, not 4 season. On the other hand, content creators like tailssofwanderlust have a Basecamp and stay in the mountains in winter all the time. But that price, though.

That's not to say you can't make a T@B, Basecamp, Lance 1475, or anything work with enough skirting, heat cable, heaters under the camper, and extra space heaters and dehumidifiers inside the camper. It's just that the 320 is just a bit small to support all that extra equipment.

grubbster · February 2021

Look at Oliver trailers if you need a 4 season. Not cheap.
https://olivertraveltrailers.com/

Nursejoe · February 2021

Thanks everyone for the informative responses. Frankly, I am surprised by the courtesy, effort, and concise information provided in the responses. I "belong" to a couple of other forums and for the most part find them to be trite, pedestrian, as well as "troll heaven" (if I understand the meaning of troll). To have a conversation of this caliber... again, all I can say is Thank You!

DougH · February 2021

@Nursejoe That content creator is not on this forum... only Instagram and YouTube

https://youtu.be/8To3842tOdw

ScottG · February 2021

There are at least a couple other owners (@tybladesmith, @Tabaz?) here who did some pretty clever modifications to winterize their trailers, including extending an Alde heat loop into an insulated "basement" to keep the tanks warm. IIRC, someone even wrote up and posted detailed documentation of their work. I not sure of their final verdict on how well the mods worked.

The mods were probably more involved than the average T@bber would be willing to tackle, but might be interesting to at least check out what they did if you are even thinking along those lines.

Tabaz · February 2021

I’ve been very happy with the results of extending the Alde loop into the basement and around the black and grey tank valves. Can’t recall the name of the post (started by another member). It is doable but not sure you can still get all the needed parts from Alde.

DougH · February 2021

Tabaz: gregp and you documented your awesome mods at:

https://tab-rv.vanillacommunity.com/discussion/7978/winter-use-of-our-t-b/p1

Nursejoe · February 2021

Thanks again all for the useful information

GatorEgg · February 2021

Just insulating doesn’t make it a 4season trailer. For example the Safari package on Airstreams adds furnace ducting to the under belly tanks and plumbing.
If 4season is needed then get one, T@bs aren’t it.

Nursejoe · February 2021

Well ok then.

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