Insulating a van with a curved/uneven surface with polyiso

Just wondering what people's thoughts are on insulating a van with walls which have a curved and/or an uneven surface? I am looking to buy a van to live out of for periods of the year and heard that  polyiso is the best product to use for insulation. Having good insulation is a big priority as I'd like the van to be as warm and draught-free as possible during winter. I've been looking at a Toyota Hiace SLWB because of the space it offers and it's driveability but I'm concerned that it might be difficult to insulate well with polyiso. Would I better off looking for a van that's more square?

Below is a picture of the Toyota Hiace SLWB.




As you can see the walls and ceiling are slightly curved and the ribs of the van (if you can call them that) don't protrude out very far and come out at different lengths.

If I was to insulate it I'd try to even out the surface as much as possible with some thin sheets of polyiso and then insulate over it again. Would this work? Maybe put some cuts in the polyiso sheets to allow for the curves on the walls and ceiling.

Or would it be a better idea to go for a van that would be more straight forward to insulate?

Any ideas are greatly appreciated!

Thanks

I just insulated with 1.5 inch poly-board - http://www.van-tramp.com/wp/big-blue-version-4-0-demo-to-blank-canvas/

The curves are easy enough to deal with; just slice along the rear side of the foam board, and snap. Leave the interior facing side foil intact so the board conforms while leaving the foil to stay as one solid piece. But honestly, having small air gaps due to the curve of the van is not a big deal at all. You will be fine.

I use the rtech foam from home depot, I use the 1/2 inch foam (cost 8 dollars for 4x8 foot section) which bends extremely well to curves. The van in the picture would be ideal for the rtech foam, get a hotglue gun and you be done in a day. Cut in small sections because the hotglue drys quickly.

With the rtech foam you can hotglue another layer over if you need more insulation. I got 3 layers on the roof and 2 layers in most other places. Some places you can get away with 1 layer, use a ir thermometer to find hotspots/coldspots and throw another layer in that section. Use as many layers as required. 

If you are going to use the hard polyiso, just cut into small sections and that will work also. I also recommend hotglue on that, it sticks to everything, drys in minutes and wont come off easily.

Dont overlook building some sort of sliding door between the driving area and rear. I have a divider build out of rtech foam sandwich by 2 pieces of thin wood, all the heat comes in from those windows. With the rear of my astrovan heavily insulated I'm very comfortable in the summer or winter. I can park in the hotsun and spend all day in my van with just a small swampcooler running, foam insulation works extremely well. If its not working, its because not enough was used. For winter you want to be as airtight as possible, I also put a removable foam section by the vans right side sliding door, I had cold air coming in from that area. 



This is a picture of the temperature in front of van and the back, without foam insulation/divider it would be about the same in both sides.

A well-controlled heat gun will allow for that much bending, check out the "foamie" builders, teardrop shape campers also boats.

Yes scoring helps, but fill gaps with poured or sprayed foam

https://vanlivingforum.com/showthread.php?pid=352495#pid352495

Bob has a couple of really good videos on the subject (I just happened to watch them recently):

Layers of thinner foam.

John61CT said:

Yes scoring helps, but fill gaps with poured or sprayed foam

https://vanlivingforum.com/showthread.php?pid=352495#pid352495

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Please don't use that 'Great Stuff' foam in a can. It can and will do more damage than you can prevent.

Also, I'm not sure what 'hot glue gun' other posters are referring to but if they're using the glue that comes in sticks in the craft section of W/M or at Michael's it has a very low melt temp which is great for crafting, not so great for using on the metal wall of a van. The glue WILL melt on even a warm day and if that's all that's holding a panel in place...well, it wont' be!

Far better to tape your panels with the aluminum tape or even the red tape that is used for holding insulation panels in place and for taping vapor barriers on house construction.

Almost There said:

Please don't use that 'Great Stuff' foam in a can. It can and will do more damage than you can prevent.

Click to expand...

I haven't, but people do, and I'm looking for some more specifics please.

I used the 1/2 inch hotglue sticks from harbor freight and also bought 6 pounds of generic 1/2 inch gluesticks from amazon (about 20 dollars). 5 years later the foam is still glue on there tight on my roof. 
Even in my driver compartment where the temperature gets over 140 degrees, the foam is still firmly attached to the roof.
But they do sell specialty hot glue sticks that melt at higher temps, but not needed for the modest temps encounter in everyday vehicule use.
Working with the hotglue is quick to apply, and no fumes, especially in confined areas. If you have ryobi cordless tools, they even make a cordless gluegun.

If you buy the high temp glue sticks and the high temp guns, you can be pretty sure it wont re-flow at normal temps found in any van during even the hottest days. 

High temp glue sticks melt at about 400 degrees. 

The main problem is of course, that it will melt the foam boards you're trying to install. 

High bond spray adhesive works well, but you still need to mechanically secure the panels, such as with screws or bolts.

Thanks for all the input!

It's reassuring to know that if I went for the Toyota Hiace SLWB I could do a reasonable job of insulating it either with polyiso or R-tech foam.

If I used polyiso and cut it into smaller pieces would the gaps be an issue? Would you fill them in and what with?

My other concern is preventing the cold coming in from the dual sliding doors. I would try and insulate them maybe with a thinner piece of polyiso or R-tech foam but it might not be possible if it interferes with the functioning of the doors. Jonyjoe303, you said you put a removable section of foam by the door to stop the cold coming in. Does it work?

A sliding door or divider between the front and the back of the van is something I considered but probably wouldn't have done. I'm now leaning towards it. I was more concerned about the cold than the heat but it definitely looks like it would be worthwhile doing.

Thanks for the videos, dawnann7. I've watched them and have bookmarked them to watch again.

Van-Tramp - your van looks awesome. Really spacious, powerful and well insulated. I like the top on it as well and the positioning of the windows.

Thanks for the tips on which glue to use as well. All very informative and very much appreciated!

Just got off from a call with a very helpful guy at Dow tech support

GreatStuff is closed cell (yes 80% rating), reasonably waterproof when cured properly but all insulated areas should be sealed up with a vapour barrier to be effective long term.

It is best for filling in small exposed gap areas and cracks, and if deep should be done in layers, 15-25 minutes curing. Not designed for filling contained enclosed spaces, needs exposure to **humid** air to cure.

Otherwise you get a very sticky gooey mess to clean up.

Warm conditions are best, and if the air is dry, spray a fine mist between layers to cure, but better to just wait for humid weather, over 30% is best.

If you screw up and think it didn't cure right, do remove it, partially cured sections left in place will off-gas forever, not just the smell, but some people get sensitized and have health issues.

I also found notes from a guy who makes custom freezer boxes for yachts, highly recommends this pourable expanding foam for sealing in and around XPS (on the cold side) and polyiso (for the rest, max R-value per inch)
http://www.uscomposites.com/foam.html

It can make a huge mess, careful to mask off well and do in small batches, work quickly.

It expands very forcefully so measure very carefully if pouring into an enclosed space, can definitely buckle sheetmetal if you're not careful.

3M Super77 is a good spray adhesive for foam

https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Super-77-Multipurpose-Spray-Adhesive

Van-Tramp said:

I just insulated with 1.5 inch poly-board - http://www.van-tramp.com/wp/big-blue-version-4-0-demo-to-blank-canvas/

The curves are easy enough to deal with; just slice along the rear side of the foam board, and snap. Leave the interior facing side foil intact so the board conforms while leaving the foil to stay as one solid piece. But honestly, having small air gaps due to the curve of the van is not a big deal at all. You will be fine.

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I'm curious how you are going to finish off the inside of the top to make it look nice.   Keep the pics coming! 

This morning got down to 46 degrees, with no heater, the inside of the van was 60 degrees. That just with the insulation and covering all the areas were air might come in. 

Besides the sliding door between the front and back of the van, I made a Foam cutout to put over that door (it had too much cold air coming in) , that help keeping front and back isolated. also the sliding right side door I have foam that comes off, wont affect door if I want to use it. 

Use several thin layers.

--jg

This thread got me super-curious about the actual temperatures involved with hot-glue!

According to https://en.wikipedia.org/wiki/Hot-melt_adhesive#Glue_gun_specifications_and_usage, 

Glue guns come in low-temperature and high-temperature (hot-melt) versions. Low-temperature glue guns operate at approximately 120 °C (248 °F) and are well suited when high temperatures are undesirable, such as gluing lace and cloth. High-temperature guns operate at approximately 190–210 °C (374–410 °F) and produce a stronger bond. Dual Temperature guns have a switch for both low- and high-temperature use.

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If my van is hitting 250 degrees, I'm doing something wrong, yikes!  Time to go up in elevation!

no matter how hot your van gets, the hotglue won't be coming off. I have some foam on the roof in the driver area, where it hits 140 degrees in the summer, after 4 years foam is still on there tight. 
Excellent glue for applying the foam. 
Only concern is wear gloves when applying it, it gets very hot. Drys quickly and no fumes when working on the interior of your van.

My question about hot glue is whether it is easy to remove cleanly. I don't want to do anything to my van that would deter a potential buyer when the time comes to sell it!