Best Ways to Improve Insulation in Newmar Cypress Walls

[rbprvf]

Hey all, Newmar Cypress with aluminum studs, think ply walls, and fiberglass insualtion. My son wants to add more insul, it's pretty cold/ drafty in winter, is closed-cell expanding foam a decent option? Drill holes, insert straw, and spray? Are there any accepted techiniques for this, or is it a dumb idea? Better to add 1/2" of polyiso foam board inside, and sacrifice a little interior volume? Any suggestions appreciated. Thanks!

 

[John From Detroit]

Not sure but at a guess multiple NOs.
For one that is rather nasty stuff for a small seal (Say around a pipe) not bad but over a large area the out-gas not good.

Second, I suspect here is not much room in the walls as they are full of something. Likely Styrofoam which is as good as the expanding stuff if not better.
You may need to add to the inside walls (a layer of something) and that's a major re-fit.


You said 'Drafty" other than doors and windows if you can identify source of draft expanding foam works there. (Small areas) on doors and windows weather seal or weather tape may help. Blanket over window may also help. I do that in my apartment.

 

[Gary RV_Wizard]

I think John hit the key reasons to be dubious of that plan. I'll add that expanding foam creates a lot of pressure in an enclosed space - I've seen it bulge plywood or fiberglass panels out of shape.

But if you can locate the gaps where those drafts are coming in, e.g. around water line coming though the floor or maybe around windows where the factory styrofoam did not quite fill the space, by all means carefully squirt a little foam in to fill that area. I've also added foam board at the back of cabinets where it's not seen but adds to the R-factor in that area. Doesn't cut storage space much. Also check the front and rear walls/caps - the factory sometimes neglects those areas. Batt insulation can be pushed into open areas there.

 

[Kirk]

I agree with both previous posts. There are different levels/types of expanding foam, so if you do use some, get one of the low expansion versions.

 

[rbprvf]

Was definitely planning on closed-cell, low expansion. Evolving plan is to do CC foam only where needed, and put 1/4" GoBoard over all the walls, which has some R-value, and makes a good substrate for a thin surface topping. Will lose very little space that way, and should tighten it up quite a bit.

 

[Mark_K5LXP]

Sounds like a lot of work and expense for an incremental gain at best. Even if the spray foam has a higher R factor than what's there you're not replacing what's there, maybe just filling in some voids. The elephant in the room is the thin roof, single pane windows, skylights, slides, on and on. So spray foam won't hurt but don't expect a huge improvement.

Mark B.
Albuquerque, NM

 

[IBTripping]

I've found that simply putting in Camco roof vent pillows make a considerable difference in heating and cooling.

 

[TXMOOSE]

That foam stuff is awsome. But not for a trailer unfortunately. Mu buddy tried 1 wall we both were thinking about how easy it would be. At least the 1 wall was easy to fix.

The wall did pop a bit and the rising stretching foam pulled some electrical wires and a speaker wire. But we took care of it using the same boards and trimming it down.
But that wall is more sound and can be pointed at the wind.
We did the addition , second floor to my uncles house. After building it he had gotten this insulation truck ( 1980 ? ) and me and him blew this stuff in. Don't know if that type would work but I know it was lite and stuck to the walls. Next day we took a 2x4 scraped each wall even for sheet rock. Nothing like the heavy foam.

Still don't know how it would be in a trailer.

 

[dcairns]

Another thought about the spray foam. Adding and repairing wiring in the future will be difficult. This is fresh in my mind as I have been fishing wires for some projects I have been doing in my trailer (LED lights, cable for battery monitor, cable for inverter remote panel). It can be a pain with just the fiberglass insulation, I can't imagine trying to bore a hole in the spray foam inside the wall.