Any Experience With Insulation?

[HanSolo]

I have recently bought a Ford E450 Box Truck which I will be converting into an RV. I have some work ahead of me!

My first job will be to insulate, and I am thinking about using closed cell Polyurethane foam for the walls. For both cost and space reasons, I would like to put no more foam than necessary into the walls.

From surfing the web, it seems like 1 to 2 inches might be sufficient. Does anyone have experience with this type of insulation? How much of a difference do you think 2 inches will make as opposed to 1?

Also, does anyone know if it is safe to spray the foam directly against the metal outsides of the box?

[HanSolo]

No there is no sheeting. Here are a few pics if you're interested.

http://www.flickr.com/photos/63401930@N05/

Maybe 3 inches would be best. I think I might make this my plan.

[westend]

If you spray 2" of foam, you' have about R14. If you cover the sprayed foam and wall studs with 1/4" polystyrene (fan-fold used for residential siding) and them install a 4 mil vapor barrier, you'll have R-16 and a complete thermal break from the exterior walls/ceiling. You can install any wall surface onto the inside. 1/4" plywood makes an excellent interior surface.

[recycler]

is there some kind of sheeting behind the boards in your truck..the drygoods bodies i have worked on had vertical members that got panels attached to if this is the case in your's it will give your another 3/4in if i remember the depth of the uprights..3in insulation would be nice and if i build another camper it will have it..good luck on your project

[HanSolo]

Spike99 thanks for taking the time to post all of your comments. This is really helpful!!

I've been so busy working to pay for all these new expenditures that I haven't had the time to log into the site.

It seems that most people recommend 3 to 4 inches of spray foam, however, a few youtube videos show people spraying 1 to 2 inches for trucks that are built for refrigeration. I'm not sure how this would be adequate for a refrigeration unit if not for an RV.

Our truck was used previously as a moving truck, so it has boards screwed into the walls. I was considering fixing plywood directly to the boards. This would provide 1 and 3/4 inches of foam behind the plywood. Not enough??? If not, then I guess we would want to remove all boards and attach vertical beams to allow more space within the walls.

We're more concerned about losing the width of our living space than we are with the extra money, but temperature comfort will come first. We want to find the point where the difference will be most noticeable, if not perfect.

It's hard for me to imagine our box truck catching fire in a way that wasn't obvious for us to immediately get out. But fire proof foam certainly sounds like an easy precaution. Pianotuna, do you know any advisable fire proof foam?

[pianotuna]

Hi,

There is also fire resistant (fire proof?) foam. That is what I'd use.

[spike99]

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Before spaying the E450 cargo box van with spray foam insulation, I highly recommend the install of a ceiling vent (variable speed) and small side windows as well. Get the small RV rated side windows that can open up. When roof top fan pushes air out, the OPEN side windows allow air to come into the large cavity. Variable speed fan motor to adjust both CFMs and sound as well. re: - click here - And, remember to install the roof cover over it. re: - click here - Note: Pick black over bedroom areas and white over living room area. Thus, control light entry as well.

For good video to install vent and Maxx air cover, surf: - click here -

Note: before screwing down the vent assembly to the roof, add some dicor sealer between the roof and vent flange. Give vent assembly a few small 1/2" twists (to squeeze some of the dicor out of the touching layers), then suck down the roof vent using screws. Thus, sealing the roof vent to the roof surface even better.

If not into large roof top fans with covers (and travel in NO snow regions), do investigate - click here -

If wondering, sealing a home, RV or even a box van cavity too much does allow moisture to be trapped inside it. Thus, best to install a power fan and "you" can manually control its air flow behavior. Just like folks install a power fan inside a RV & home's bathroom.

Hope this helps as well...

[Golden_HVAC]

What do you plan on using for the interior surface? Perhpas the foam can be sprayed directly onto the inside ofthe box van walls, then the inner surface attached to stop the foam from over expanding, and also will hold that surface in place - sometimes very tightly!

The recommendations to do all the wiring first is a great one, then you will not have to cover the wiring, it will be encased into the foam. With the inner surface attached to the still expanding foam, it should stick in place, and you will have a very vibration free wall system.

Check with the installers about the R value per inch of installed foam. Some are better than others, and most provide a 100% draft free vapor barrier.

But it is also hazardous to spray, you need supplied air respirator with emergency egress system, no cartridge will filter out the air, it is brought in from another room, or the outdoors. The egress system is a 2 minute oxygen container like a SCUBA tank, you carry it with you, and should your air line get tangled, you disconnect and get out before the 2 minutes is up, or hold your breath!

If your intention is to install the 1" thick or 2" thick panels already expanded, and sold at Home Depot and other places, there is no hazards to that material (unless it catches on fire - then look out). You can cut it and fit it around anything that is in the way, then put up a interior panel, to make it look nice. It will still vibrate, and should provide up to R3 or R4 per inch of thickness.

You might also look into Reflex bubble wrap type insulation. You can buy it in 4' wide rolls, I bought 125' long one to insulate the attic around my sister's A/C unit, and all the ductwork, installing an additional R4 to all the ducts I could reach, then lined the room the HVAC unit was located in with more Reflex, insulated the cabinet itself, so the coldest air in your whole house (51F typically while it is running) is within the A/C cooler cabinet, insulated from 115F attic temps by 3/4" of fiberglass (R3?) and I increased that to R-7 or so.

It can be stapled to the paneeling that will become the inside wall surface, then the wall surface installed. Ot can also be taped to the exterior walls of the box van (inside of course) with good duct tape, and will also create a vapor and wind barier. I was thinking about putting Reflex under my carpet in my RV, but being exposed to the heat of the engine might be to much for it, and walking on the Reflex should pop the bubbles, making it useless.

For the doghouse lining, air duct liner about 1" to 1.5" thick will provide about R4 insulation to keep the heat out. It is also flame resistant, and will not support flame spread (I tested with a BBQ lighter, the flame would not start on the material, or spread, or damage it much).

Good luck on your project.

By the way, a domestic refrigerator can not run on a modified sine wave inverter. High torque motors like in a refrigerator would require a pure sine wave inverter.

Fred.

[spike99]

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For a good comparison of fibreglass batt insulation vs. "inner cavity" foam, surf: - click here -

This RV foam video is worth watching as well.

Hope this helps as well..

[spike99]

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Forgot to mention...

If spray foam is burned, its killer smoke instantly knocks down humans. Many spray foam companies recommended a fire protection covering "over" their spray foam as well. Especially where humans might sleep.

If their fire protection spray (over the spray foam layer) is too expensive, and your inner walls are flat surface, do investigate cement board covering as well. Same cement board (with proper galvanized screws) that folks install in their bathroom shower walls (before tiling the walls). re: - click here - If wondering, this cement board is available at home hardware type stores as well.

When my RV/TTs inner walls needs spray foam, I'll be applying cement board in the bedrooms. Then, install the normal 1/4" wall paneling sheets over the cement wall board. And, installing a smoke detector in each RV/TT bedroom as well. Thus, increasing human safety (from killer smoke) protection as well.

Hope this helps as well..

[spike99]

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Spray Foam (2 lbs / medium density) Closed Cell "contractor grade" within RV walls, ceiling and underbelly is an amazing product. If wondering, I applied 3-4" under my 2006 TT and am very impressed with its before and after results. Not only did it create 7.5 R "per inch" with vapour barrier, Contractor Grade spray foam also tightened up its floor movement. IMO, Spray Foam insulation should be minimum factory build in all RVs - just like housing industry is realizing that Spray Foam in outside house walls is a great thing as well.

Lessons learned:
- Stay away from those diluted DIY Kits - like Tiger and other companies. Only use Contractor Grade foam.
- You can tow your RV/TV to their spray booth. Or, you can ask them to visit your RV location with their mobile truck. Either method works great.
- To reduce costs, do as much before preparation tasks yourself. Simple DIY stuff like taping plastic sheets on the over spray areas. And, ensure inner wall wires / PEX piping is in excellent condition (before spraying). And where needed, created access door boxes - where one might need access (like behind the tail light assemblies (to change a blown bulb from the inside).
- To reduce costs, do offer clean-up tasks as well. For example, you remove overspray plastic sheets, you clean up the over spray droppings, etc. etc.
- Ensure all needed speaker wiring, 12 volt wiring, electrical wiring, etc. etc. are installed - before Spray Foaming task as well. If you think wiring might be replaced or pulled in later on, simply install some 1/2" flexible PEX or PVC plastic piping and if needed, use wide smooth corners. Thus, one can "fish" replacement wires to that specific spot (like TV/DVD/Media Player) later on.

For a good video showing contractor spray foam in a Sprinter van, surf: - click here -

For good video showing contractor spray foam in large box van, surf: - Click Here -

To view the spray foam (contractor grade with their mobile truck) under my 2006 Jayco, surf many pictures within: - Click Here -

Would I install "contractor grade" Closed Cell Spray Foam 3"-4" thick under my RV/TT again? YES. Without hesitation!!! Amazing upgrade with amazing results. Especially since we plan to keep our 2006 Jayco 29ft RV/TT for 5+ years.

Note: Do shop around because prices for same contractor grade spray foam does dramatically vary. I found one local company at nearly 1/2 the cost of others. And, he didn't charge me travel time (because my RV location was on the way to a very large job).

If there's a wide 18" inner wall cavity that has smooth surface (re: no spots for the liquid foam to stick to), simply install some galvanized wire mesh. Same galvanized wire mesh (available at many home hardware type stores) that's used on rabbit cages. Then, spray foam over this wire mesh. Vision same effect as steel re-bars in a cement floor - before pouring the liquid cement on the floor.

Hope this helps.

[pianotuna]

Hi,

I'd go for more than two inches. Spray foam--if done on the outside--what will you cover it with?