When the foam expands it applies significant force.
Yes, it does. But unless the atmospheric pressure inside the van is significantly greater than that outside the van, or there is some other interior constraint, the force of the expanding foam will push inward from the inside wall into which is was sprayed. Foam sprayed inside ribs, as long as it has a path of escape, then it will not be able to exert any pressure at all on the walls of the van.
This waviness was 100% caused by foam installation and this is a much more common issue than people realize
I don't think it's a much more common issue than people realize at all. I think it's a rare event. In fact, based on my own observational experience of looking at vans almost daily, I feel more than confident that it's a rarity, indeed. It's certainly not common at all, and there would have to be very rare circumstances which could cause such a rare event. You have people in this forum, me included, who have researched this like crazy, and have observed the results of spray-on foam. If it were much more common, someone would have mentioned it by now, since, you know, people have been insulating these things with spray on foam for a long time now.
If that waviness was 100% caused by foam insulation, which I don't believe for a minute, then it wasn't 100% the foam, it was 100% because someone did something to allow the conditions to occur, like as OVM said, installed fixed plywood walls or some other constraint that did not allow the foam to expand. And even that would be a tough one to accomplish with spray foam that was sprayed onto a surface and not directed through a hose.
What happens is the foam is sprayed within the ribs and a combination of heat and expansion causes the metal to deform.
That sounds more like speculation from faulty reasoning. One, if it can be sprayed within the ribs, it can escape from the ribs. I know that because I've sprayed foam within ribs and watched it expand right out of them. Two, the expanding foam does not generate even remotely close to the kinds of temperatures that will deform the sheet metal of a Sprinter wall. Again, the physics don't add up.
A far more likely explanation for the deformation on that van is, something broke loose inside the van and damaged the walls, and the driver/owner tried to pound it back in shape, and then, rather than admit to not being able to properly secure the load, he blamed it on foam insulation.
The gauge on the Sprinter wall may also be a contributing factor.
If it were, then it wouldn't be "may" is would be "is".
This is pure speculation, also. He states,
""IF" this type of insulation gets between two panels that arnt welded or bonded it "could" cause stress on the outter body panel and bow or push out the panel." That's a big IF and a big COULD. The problem is, the Sprinter's 1/4 panel walls do not consist of two panels that aren't welded or bonded.
The reply immediately following that post replaces speculation with actual results, anyway.
There are installers out there who go to great lengths to protect against this. golfournut, you should inquire - but I'd be surprised if you got a guarantee.
Could be, and caution should be taken. Still, there us simply no way that spray on-insulation of the type shown in the picture below could cause the wavy deformation shown in the picture you posted. No way, no how. It's physically impossible.
