Close Cell Foam Spray

[keightley]

So I think I have pretty much decide to go with close cell foam spray to insulate my van.  It has a good r-value.  It is impermeable to water vapor.  It has sound deadening properties as well.  I am not installing this myself.  I will be hiring someone to do it for me.  So as a side note, if anyone has a recommendation where I can go and get this done in Salt Lake City, I would appreciate it. 

All that said, I do have questions about this type of insulation and installing the electricity, plumbing, and sound system.  From what I have been reading, these systems should be installed before the spray foam.  But what if I don't know the layout of my van?  Can this be installed on top of the insulation?  Furthermore, won't adding these systms after the insulation make it easier to access and repair them should they be damaged in some way?

I would like to know your thoughts on the matter.

Cheers,
Keightley

 

[Almost There]

Personally, I would do it after the spray insulation is installed.

You're right, moving wires and repairing things will be much easier if it's not buried in the foam. And since this is your first build??, you're more likely to want to change things out as you experience the nomad lifestyle and figure out what works for you.

The concept of doing it before the insulation applies more to S&B applications than to a mobile situation.

 

[VanKitten]

Everything I was told, and read about spray foam was...don’t do it.....

Spray on foam insulation was tried by Airstream in a few 1969 entrance doors. It turned to powder from the rubbing and vibration.

Dometic used it in the reefer doors. Again a huge failure.

Spray in foam also contains formaldehyde, which has been deemed very unhealthy to breathe.
Trailers that were quickly made for victims of Katrina, contain spray insulation, that the feds are raising devil about, because it has been causing many health problems.

Spray on foam insulation, if you don't mind the health hazard, will not take vibration of any kind. Vibration will cause the foam to turn to powder.

 

[keightley]

As with most products, I am sure there are "unsafe" closed cell foams. But I am also willing to bet there are "green" closed cell foams. It most likely depends on the brand and the installation method. Quite possibly the DIY close cell foams are not as safe as closed cell foams applied by a professional. So I am not ready to ditch the entire idea. Besides, I have have no intent to DIY the insulation.

 

[RenataAllison]

Thanks roaming Kat that pretty much answered my questions on exploring foam as an option.

Sent from my SM-N950U using Tapatalk

 

[Chuck1]

Uh, your talking about old design mixed urea formaldehyde foam not polyisocyanurate, modern foam has no formaldehyde nor does it turn into dust, Its used in 1000s of products and vehicles of all kinds.

Commercial trucking runs billions of mile with with sprayed in wall foam, if it didn't work they wouldn't use it.

Oh and Santa isn't real.

 

[Headache]

Commercial trucking runs billions of mile with with sprayed in wall foam, if it didn't work they wouldn't use it.

I can definitely vouch for this.  Many of the trucks I drove had foam insulation sprayed on the sleeper walls.  It didn't turn to dust unless it was the older crap.

 

[rvwandering]

We have a small class C that was custom built. The walls and ceiling have spray on foam and the floor has pour in foam. It really does a good job keeping the interior warm in cold weather and cool in hot weather. The only problem we had is a slight waviness on the exterior walls because they weren't strong enough for the expansion of the foam. All the wiring and plumbing was installed after the foam was in.

We've driven over 130,000 miles and the foam has not deteriorated at all. One small area needed insulation as the build progressed and spray can insulation was used. That stuff is awful. It squeaked and crumbled. We dug all of it out.

 

[John61CT]

The only problem we had is a slight waviness on the exterior walls because they weren't strong enough for the expansion of the foam.

This is a real problem, but not hard to work around.

A.) Ideally the space being filled is not completely enclosed, there should be plenty of "escape route" for excess foam so undue pressure is not exerted on the walls.

But vehicle body sheet steel is *so* thin these days, if in doubt I'd first glue some foam lining to the steel to help absorb / spread the expansion pressure.

Best to just spray a thin layer at a time to an open surface, can always spray some more after it's cured.

Using rigid foam panels for the bulk of the job, spray/pour to fill in corners and gaps will be both cheaper and more effective insulation.


B.) if the above is not practical, and you do need pouring or spraying into an enclosed space, try to calculate the volume expansion ratio

for the given current temperature, varies *enormously* for a difference of just a few degrees!

as precisely as possible, and round down to make sure you don't overfill the space.

There is no problem doing multiple batches in layers.

Obviously carefully read and follow all the directions and data sheets carefully, especially wrt to temperature ranges, don't bother trying in cold weather.

If the foam doesn't cure properly, it will be offgassing for years.

BTW heavier densities do provide better R-value.

 

[Chuck1]

Using rigid foam panels for the bulk of the job, spray/pour to fill in corners and gaps will be both cheaper and more effective insulation.

I think that's a good way to do it and what i will do in the future to save a little money, spray an inch coat to vapor seal, then run wires-plumbing then use sheet to bring the R value up to the point you want, Can-spray foam to fill gaps on the sheet foam.

 

[John61CT]

If you're doing 2-part spraying anyway, use that for after as well, canned stuff not as good.

IMO no need for that first spray, the important vapour barrier is the inside envelope against the humidity from the living space.

A bit of gapping between a straight foam board and a curved wall is NBD.

If you do do that, then an inch is overkill, remember the spray kit is way more expensive and less R-value than the polyiso.

By the way, for extreme cold, put a layer of XPS board on the cold side of the polyiso, say up to an inch but not more than about 20% of the total thickness.