Dow Froth-Pak Spray Foam Installation

[TheHubbardBus]

Originally Posted by o1marc

Isn't the purpose of the breaker to avoid just such issues?

No, a simple breaker exists to prevent current above that which you sized the wire to conduct from flowing (as would happen in a short-circuit condition).

The hypothetical problem we're discussing would be caused by failing to size that wire correctly, because you didn't account for the additional heat created by running it in conduit, bundling it together, confining it in other matters, high ambient temperatures, or a combination of such factors.

I say hypothetical because, as family-wagon taught us (thanks for that, fw! ), apparently it's not the problem I assumed it to be! Color me surprised. You learn something new every day.

Sorry, Comfort. That's the end of my hijack. Back to more important matters...

YOUR FOAM JOB ROCKS!!!!!!!!! MAJOR KUDOS!!!!!

[o1marc]

Originally Posted by TheHubbardBus

No, a simple breaker exists to prevent current above that which you sized the wire to conduct from flowing (as would happen in a short-circuit condition).

The hypothetical problem we're discussing would be caused by failing to size that wire correctly, because you didn't account for the additional heat created by running it in conduit, bundling it together, confining it in other matters, high ambient temperatures, or a combination of such factors.

I say hypothetical because, as family-wagon taught us (thanks for that, fw! ), apparently it's not the problem I assumed it to be! Color me surprised. You learn something new every day.

Sorry, Comfort. That's the end of my hijack. Back to more important matters...

YOUR FOAM JOB ROCKS!!!!!!!!! MAJOR KUDOS!!!!!

Would the heat build up not effect the flow, thus tripping the breaker?

[TheHubbardBus]

Metallic conductors increase in resistance with increasing temperature, so if the increase in temperature did have any significant effect, it would be to reduce current - not increase it.

Now, if you did end up overheating the wires, and it burned off the insulation, and you were lucky enough to short to ground in the process, then the breaker would trip. But that's not what it was designed for, and by that time, you may have already started a fire.


Sorry Comfort...

[ComfortEagle]

I finished trimming the foam today. After trimming larger chunks with my trusty bread knife, I ended up shaving the remainder with a belt sander and an 80 grit belt. The sander was very effective but also very messy. I wore a respirator, but my googles were trashed from the foam application so I ended up wearing an old full face motorcycle helmet with the visor closed...

It took several passes with the shop vac and blower to clear all the dust out of the bus, but I don't regret using the sander. I spent ~2 hours shaving the foam with a knife, and another ~2-3 hours with the sander, but it is done.

There are a few small gaps that I will fill with some Great Stuff, and there will likely be a few places that will need some spot trimming, but I am calling this task complete.

To summarize my experience:

1) DIYing the foam was not as scary as the anticipation of DIYing the foam... It's a big, expensive, and messy job, but in my experience not technically difficult and within the capability of most skoolie builders.

2) Speaking of messy, when spraying, anything not protected will get foam on it. Scraping the floor was not too tough, but if I were doing the job again I would probably tape some paper to the floor.

3) Also, in the messy category, while applying foam to the ceiling, a ball of foam consistently began to form on the tip of the gun. Not a big deal, but it needs to be pulled off every now and then or the spray pattern will be affected.

4) More messy... Trimming foam with a sander, grinder, etc. is MESSY, however it greatly reduced the time and energy needed to finish the job. Vacuuming dust is way easier than manually trimming foam. Leaving the plastic over the windows on until trimming was done would also have been a good idea.

4) Don't panic; take a breath; take your time; you have more time than you think. If you stop spraying for more than ~30 seconds you will need to change the nozzle; this is not a big deal. My kits came with plenty of extra nozzles, and I have many left over...

5) You will probably (and should) run out of foam before you run out of stuff to spray foam. If I were doing the job again I would re-prioritze my application plan to get the foam where it's most needed first (ceiling).

Anyway, a few pics of the finished job are below. Again, it's not perfect, but when it's covered with ceiling planks it will be (perfect). Onward and upward...

[RVWorldTraveler]

I had a company do the spray foam for me and i'm glad I did. About a week after it was done all the ceiling panels started to come off of the roof. I told the company what had happened and the gladly removed and resprayed any panels that came loose, roughly half of them. If i had done it myself i would have been on the hook for another froth pack. Initially it may have costed more, but it was peace of mind knowing that it was covered in case something went wrong.

[Native]

Wow, that ol' turkey carving knife sure did a nice job!


Now that it is over, I am sure it is done. Did you use a vacuum attachment on the belt sander?

[ComfortEagle]

Originally Posted by RVWorldTraveler

I had a company do the spray foam for me ...

Thank you for your feedback.

Originally Posted by Native

Wow, that ol' turkey carving knife sure did a nice job! Now that it is over, I am sure it is done. Did you use a vacuum attachment on the belt sander?

Yes, the magic knife... And no, I did not use a vacuum attachment on the sander. That would have definitely helped reduce the mess. Although holding that sander over my head for 3 hours with a hose attached to it would have been an even more challenging workout for my shoulders.

[TheHubbardBus]

Has to feel great to have that job behind you!!!! It looks awesome.

So... how does it feel (as in, compared to ambient)?

[ComfortEagle]

Originally Posted by TheHubbardBus

Has to feel great to have that job behind you!!!! It looks awesome. So... how does it feel (as in, compared to ambient)?

Thank you; having that job complete is very satisfying. I am anxious to start on the ceiling planks...

As for the temps in the bus, generally cooler with windows open, but not a huge difference. One more coat of paint on the roof and I will be ready to install the solar panels and decking (mostly solar panels). It should be nice to have the bus roof perpetually in the shade (and for the bus to generate it's own electricity; the mini-split will follow).

One big difference from the foam is that there is no more condensation on the inside of the roof. Before spray foaming, on some mornings the condensations was so bad that the inside of the bus would rain (drip) with the moisture.

I'm considering a layer of radiant barrier between the foam and the ceiling planks; wondering if it would be worthwhile? Guess I'll do a little more research...

EDIT: Just read this article from the DOE, it says "To be effective, the reflective surface must face an air space." Guess that answers my question, no sense in sandwiching radiant barrier between any two surfaces......

[Drew Bru]

Originally Posted by ComfortEagle

It should be nice to have the bus roof perpetually in the shade

You'll be pleasantly surprised, it made a tremendous difference in our bus.

[Frogpondfoug]

I contiplated it for awhile, professionally insulated only cost 1049 Canadian

[Sleddgracer]

Originally Posted by Frogpondfoug

I contiplated it for awhile, professionally insulated only cost 1049 Canadian

that saved some energy on your part and likely cost little more than doing it yourself ( unless you add in the beer you drank while watching the job being done - lol )

[ComfortEagle]

Originally Posted by Frogpondfoug

I contiplated it for awhile, professionally insulated only cost 1049 Canadian

Looks like they did a fantastic job. Did they shave it too for that price? Either way awesome value.

I am enjoying installing the rigid foam.

[tugboater]

Originally Posted by ComfortEagle

Thank you for your comments. I agree that this is not a job for the faint of heart. It was/is a scary proposition: as you said most of us only get one chance to get it right. And getting it wrong could be super messy, expensive, and time consuming.



In terms of the "knowing what you know now question" I would absolutely do it again.

Still catching up on all these informative posts. The “absolutely do it again” is the kind of comment all us inexperienced DIY types need to hear. Great photos & nice work! I’m excited for our upcoming insulation phase. It seems like such a big milestone during these conversions.

[ComfortEagle]

Originally Posted by tugboater

Still catching up on all these informative posts. The “absolutely do it again” is the kind of comment all us inexperienced DIY types need to hear. Great photos & nice work! I’m excited for our upcoming insulation phase. It seems like such a big milestone during these conversions.

Thank you for the positive feedback. I can't believe it's been almost three months since I did the foam. The conversion is starting to finally take shape, and that foam was a huge milestone. I hope the winter doesn't slow things down too much; I want this bus done...