Idea: spray foam to fill space between bus roof and corrugated roofing?

[Mr. Beefy]

Yet another derailment. The reading comprehension in this thread has been surprisingly poor! I have gotten some useful information in my private messages though, thanks for that! Understandably regular members of this forum who have actually read my posts and are open to this idea don't want to publicly get on the wrong bandwagon.

1. The windows are sealed
2. The main purpose of the theoretical roof would be more insulation than would otherwise be possible, mostly for the cold months.
3. It would barely be visible from the ground and would add very little weight/bulk

When everyone is having problems with 'reading comprehension', maybe it isn't the readers that are the problem. Your initial post made it clear your primary concern was the window leaks, and your primary method of addressing the leaks was this roof idea of yours. Now they've magically gone from 'inherently leaky' to 'sealed' . Backtrack all you want, but understand you're contradicting your orginal post, which means any misunderstandings are yours to own. No-one here gets paid to offer free advice. You might want to keep that in mind as you diss the folks taking time out of their day in an effort to help out a stranger (you).

As for the ceiling, that's interesting and does reflect well on your thermal break. In my experience using a half inch thermal break over the ribs the ceiling has not been great at insulating in the winter. I'd be curious to see what temperature reading you get under the ribs versus between them. I think that's been covered pretty thoroughly in other threads though.

How would you know what impact heat transfer through the ribs, and whatever you have covering them, has on the overall insulation level of your bus? That's like picking one hole out of a sieve and blaming it for the sieve's inability to hold water. Your experience is meaningless unless you have the ability to actually measure or calculate the heat gain/loss through the ribs, while also being able to measure/compare the heat gain/loss through everything else, so you can compare the two and determine whether it's a significant fraction worthy of your time/effort/money to address.

FYI the temperature read off a surface is not sufficient to answer these questions. Consider a 1/2" copper rod lying next to a 12" diameter copper pipe, both at the same temperature. Which one do you think is capable of transferring more heat over a given period of time? There exists no amount of insulation that will prevent the internal temperature from becoming the same as the external temperature (excluding radiant heating effects, etc) given enough time without additional inputs. If you don't understand this, you don't understand how insulation works.

My main question is whether closed cell spray foam can be injected into a small horizontal space like that. Maybe I should have just said that and left out the details

Spray foam insulation is not designed for blind recesses / enclosed spaces as far as I'm aware, though maybe there are variants that are. I can't speak from experience but personally I'd be concerned with the potential for unfilled voids, warping/distortion of the materials surrounding the foam, eventual delamination, and possibly inconsistent / incomplete curing. Probably a better question for a professional outfit though.

 

[musigenesis]

This means that water from the roof runs straight through the windows even after removing and re-caulking them. The windows themselves are just inherently leaky.

Yet another derailment. The reading comprehension in this thread has been surprisingly poor!

...

1. The windows are sealed

Perhaps the writing comprehension in this thread is equally poor. Bus windows are not inherently leaky; if yours are still leaking, it means you haven't sealed them correctly.

 

[Andrewclimbs]

When everyone is having problems with 'reading comprehension', maybe it isn't the readers that are the problem. Your initial post made it clear your primary concern was the window leaks, and your primary method of addressing the leaks was this roof idea of yours. Now they've magically gone from 'inherently leaky' to 'sealed' . Backtrack all you want, but understand you're contradicting your orginal post, which means any misunderstandings are yours to own. No-one here gets paid to offer free advice. You might want to keep that in mind as you diss the folks taking time out of their day in an effort to help out a stranger (you).

Now that's not a fair assessment... Someone actually PM'd me wednesday saying I should ignore the "a-hole" comments not my words but not wrong either. I think some people were confused when I described my [admittedly faulty] memory of my leaking windows in the first post, but I said a LOT more than that in the post and the entire discussion... that's ok, people miss details, but ugly comments when someone didn't read, I don't get that. Some people have also taken time to lend advice, and I certainly appreciate it

"backtracking"... I stated early on in response to DeMac that I had been wrong and it was indeed the glazing that had failed...and that the spray foam should (I think?) seal any leaks from the inside. Owning my faulty assessment/memory is not the same as magically changing my story and contradicting myself, and the crux of the discussion has never been whether my windows leak or not

How would you know what impact heat transfer through the ribs, and whatever you have covering them, has on the overall insulation level of your bus? That's like picking one hole out of a sieve and blaming it for the sieve's inability to hold water. Your experience is meaningless unless you have the ability to actually measure or calculate the heat gain/loss through the ribs, while also being able to measure/compare the heat gain/loss through everything else, so you can compare the two and determine whether it's a significant fraction worthy of your time/effort/money to address.

FYI the temperature read off a surface is not sufficient to answer these questions. Consider a 1/2" copper rod lying next to a 12" diameter copper pipe, both at the same temperature. Which one do you think is capable of transferring more heat over a given period of time? There exists no amount of insulation that will prevent the internal temperature from becoming the same as the external temperature (excluding radiant heating effects, etc) given enough time without additional inputs. If you don't understand this, you don't understand how insulation works.

I'm not sure what point you're trying to make, but I don't think anyone disagrees that without some awesome thermal imaging equipment and trials we're left to speculate

 

[Polarweasel]

You’ll all be shocked to discover I’ve deleted a couple of posts. To all concerned: please try to keep things constructive, and assume others have good intentions.

 

[Andrewclimbs]

Eghh my phone

 

[DeMac]

You’ll all be shocked to discover I’ve deleted a couple of posts. To all concerned: please try to keep things constructive, and assume others have good intentions.

------------


(Thank you & ditto)

 

[Andrewclimbs]

Eghh my phone

 

[Andrewclimbs]

You’ll all be shocked to discover I’ve deleted a couple of posts. To all concerned: please try to keep things constructive, and assume others have good intentions.

Well that was mighty quick :Thanx:

 

[RGFlinn]

No matter how much insulation you put in the roof, you still have single-pane glass surrounding your roof. The heat loss/gain through all that glass, even parked in shade, will be considerable. I'd decide which windows can be eliminated to increase the amount of insulated walls you can create.

 

[Diryco]

Ihave a 07 C2 my windows were so bad, leaky cracked plastic broken latches etc I ended up junking them and reskinned and am planning on installing rv windows they were just to far gone to consider repair or replacing

 

[Meathead]

Submitted for your approval - Rod S.

I too considered foam on the roof. Commercial and residential metal roofs are sprayed on the outside all of the time. My neighbor has this on his roof. It looks like a snow covered roof, in New Orleans, where it last snowed in 1965. Quirky much? [emoji44]

He has to apply an approved paint every 3 years to maintain his warranty.
I figured this could be applied to my bus. If I had framework running fore and aft on both sides of bus no one would see to snow on the roof. Think of a Wanderlodge type roof rack all foamed in.

What I’m saying is. Frame it. Foam it.
Roof it. Then not to worry about what will cure in a tight space. Or don’t roof it at all. Foam holds up to higher winds than your busses speed can produce!

I wound up placing a piece of ridged foam between the roof ribs and adding aluminum over the top. Then screwed into to roof ribs with metal roof screws. I have access to used aluminum construction signs. Shoulda placed them orange side up tho. You don’t need an instrument to tell the difference in temperature between two signs, one up and one down. You wouldn’t see the orange unless I was in a ditch. And that would be a good thing!

This provides a little insulation and water does not sit between the roof ribs like it did before.


[emoji3522]Dave

 

[Rochey6957]

https://fb.watch/cPsbXx47pU/