Henry's Tropicool, and how I learned to dislike it...

[shaymcquaid]

Greeting Bus Peeps...

So, I did what a lot of us do. I put Henry’s Tropicool on my bus roof....and I’m really regretting it!!!

Let me explain:
Before I did the roof with Tan Tropicool 887 I didn’t have any leaks. I did it just as insurance for future leaks. Thinking I was stacking the deck in my favor.
Now, fast forward 2 months:
I am now to this day chasing leaks!!!
Seems to me that these buses are put together in a fashion so that the water sheds like a roof shingle.
Now that I have closed all the routes the water used to take with the rubber roof coating the water manages to find its way into the bus at weird spots.
Lots of weird spots!

My Thomas MVP has two “ribs” they run fore to aft and now that just hold water on top of the bus and it gives it the opportunity to find ways in.
I have mopped every seam trying to exclude the water , but it’s slow going and frustrating😜
Maybe I’m dense or maybe I just don’t know what I’m doing, but I thought I’d put this out there in hopes that my experience might be useful.
-Shay

[Native]

Long time no see, Shay! It is a shame you are now chasing leaks after all you have done with your bus. Can you park it on an incline while all the rains are happening here?


Edit: Did you use EternaBond or a similar seam sealer?

[shaymcquaid]

Hello Native,
No, it’s not done!��
Maybe that was my mistake not using seam sealer.
I thought this rubber coating would do that!��*♂️

[schoolbuscraig]

I am not a big fan either, the white Tropicool I coated my roof with looks dirty all of the time. Good luck with your leak!

[PitskyWitbulls]

Originally Posted by shaymcquaid

Hello Native,
No, it’s not done!��
Maybe that was my mistake not using seam sealer.
I thought this rubber coating would do that!��*♂️

I'm getting ready to do my roof. I would like something to reduce the heat inside. After reading this thread I'm glad I hadn't dropped the $250 on Henry yet. Any type besides an elastomer you think would work better? I've had enough problems, I don't want to add to it.

[Native]

So far, our use of EternaBond seam sealer on ALL seams and ALL rivets followed by three coats of Ames elastomeric roof coating has kept the one weeping leak in the back out and no more have arrived. This has been two years now.

[musigenesis]

Originally Posted by PitskyWitbulls

I'm getting ready to do my roof. I would like something to reduce the heat inside.

No paint of any kind will provide any insulating value. All that paint can do as far as temperature control is concerned is to reflect sunlight, which would otherwise raise the temperature of the bus well above the ambient temperature. Any white paint will serve that purpose.

For temperature control when you're not in direct sunlight, you need to insulate inside with spray foam, XPS, rock wool etc., and the effectiveness of this insulation will be a function of how thick it is. There is no magical substance in the world that can be applied in a layer as thin as paint that will provide a significant R-value; even aerogel, an absurdly expensive high-tech insulating material, only has an R-value of 10 per inch, so a 1/32" thick layer (about the recommended thickness for elastomeric paint) would provide an R-value of 0.3125.

[Caplansail]

What would the pros and cons be of sealing and painting the roof (regular paint), and coming back later with elastomeric paint if desired?

[EastCoastCB]

properly sealed and painted there's no need for elastomeric.
That would kinda be like putting a bandaid on after a wound has healed.

[Native]

Originally Posted by Caplansail

What would the pros and cons be of sealing and painting the roof (regular paint), and coming back later with elastomeric paint if desired?

You *can* do it ... but like EastCoastCB said ... there is no need. I have elastomeric coating on our bus *instead* of paint. It seemed to be very easy to apply a thick set of coats.

[PitskyWitbulls]

Originally Posted by musigenesis

No paint of any kind will provide any insulating value. All that paint can do as far as temperature control is concerned is to reflect sunlight, which would otherwise raise the temperature of the bus well above the ambient temperature. Any white paint will serve that purpose.

I don't know... the Bussy McBusFace YouTube series used Henry's and said they noticed an immediate drop in inside temperature. They said they were no longer burning their hands on the ribs and that was in the AZ sun. Also, studies do show a 12 degree average drop in surface temperature by using just white paint on rooftops and that would translate to a lower interior surface temperature. If white paint alone drops the surface temp, then RV roof coats SHOULD reduce surface temps even more.

I already have insulation in my ceiling. Not spray foam but the reasons why is a whole other nightmare. I'm just looking for any way to reduce interior temps, seal the seams (not that I have any leaks), and protect the rooftop from AC condensation.

[ol trunt]

"If white paint alone drops the surface temp, then RV roof coats SHOULD reduce surface temps even more".

I'm not able to see the relationship. What am I missing?
Jack

[PitskyWitbulls]

Originally Posted by ol trunt

"If white paint alone drops the surface temp, then RV roof coats SHOULD reduce surface temps even more".

I'm not able to see the relationship. What am I missing?
Jack

White paint alone isn't as thick and it doesn't contain any special reflective components. RV roof coats are thicker and contain reflective additives.

I understand the studies linked are on buildings not a school bus but an 87F drop is still significant.

https://www.bbc.com/news/world-48395221
https://heatisland.lbl.gov/coolscience/cool-roofs

[EastCoastCB]

Originally Posted by ol trunt

"If white paint alone drops the surface temp, then RV roof coats SHOULD reduce surface temps even more".

I'm not able to see the relationship. What am I missing?
Jack

I'm not either, Jack.
CB

[ol trunt]

I read both articles and neither mention an advantage gained by "thickness" but rather by virtue of being white.

I've nothing against Tropicool--the fact that it's white and good at waterproofing is reason enough to use it I suppose. That it contains special reflective components or additives is not supported by the information offered by the mfg.

https://henry.com/retail/white-roof-...e-roof-coating.

Features
100% waterproof
Rain-safe in 15-minutes
Wide application temperature range from 35° F to 120° F (2° C to 49° C)
Save energy by reflecting heat
Excellent adhesion and flexibility
Permanent ponding water resistant
Superior UV resistance and weathering characteristics
VOC compliant; solvent-free
Mold and mildew resistant
Chemically bonds with roof substrate as it cures
Easy to apply by spray, roller or brush
Lifetime limited warranty with 1-coat application

Just as an aside, smooth, shiny white surfaces reflect better than rough, dull white surfaces.
Jack

[PitskyWitbulls]

Originally Posted by ol trunt

I read both articles and neither mention an advantage gained by "thickness" but rather by virtue of being white.

I've nothing against Tropicool--the fact that it's white and good at waterproofing is reason enough to use it I suppose. That it contains special reflective components or additives is not supported by the information offered by the mfg.

https://henry.com/retail/white-roof-...e-roof-coating.

Features
100% waterproof
Rain-safe in 15-minutes
Wide application temperature range from 35° F to 120° F (2° C to 49° C)
Save energy by reflecting heat
Excellent adhesion and flexibility
Permanent ponding water resistant
Superior UV resistance and weathering characteristics
VOC compliant; solvent-free
Mold and mildew resistant
Chemically bonds with roof substrate as it cures
Easy to apply by spray, roller or brush
Lifetime limited warranty with 1-coat application

Just as an aside, smooth, shiny white surfaces reflect better than rough, dull white surfaces.
Jack

I never said Henry's contained anything, I said RV roof coats. Some do contain additives as expressed in the first article. I think white lime counts as an additive to the white reflective paint

[musigenesis]

Originally Posted by PitskyWitbulls

I don't know... the Bussy McBusFace YouTube series used Henry's and said they noticed an immediate drop in inside temperature.

So I think what happens is:

1. Person buys bus with yellow roof
2. Person paints roof with Tropi-Cool
3. Person notices immediate drop in temperature
4. Person swears by Henry's forevermore

So the stuff does work as advertised and it does reduce internal temperature (at least in direct sunlight), but the real test of its effectiveness would be in comparison to ordinary white paint - which would also produce a noticeable drop in temperature when applied. I've never tested the two side-by-side myself (although it actually would be pretty easy to do, and I think a user here actually did that some time ago and found Tropi-Cool to be a tiny bit better than regular paint).

I think some of the confusion around the stuff comes from Henry's claim that it "reflects heat" which is kind of a misleading/nonsensical phrase in physics terms. Heat will transfer to a bus via conduction, convection and radiation. Of these three, only radiation can be "reflected" in any sense, but radiation will only be a significant source of heat input when you're in direct sunlight (or maybe when your bus in on fire, or less alarmingly when your wood stove is going). And that reflection can be achieved by any white paint (with a little variation).

But the term "reflects heat" seems to lead people to think that Tropi-Cool also resists heat transfer via conduction/convection, which it doesn't because it can't - there's no way a layer of anything 1/30" thick (about the recommended application thickness for elastomeric paints) will have a significant effect on that. So if the sun's not out, Tropi-Cool isn't doing anything except keeping the water out (which it apparently can't be relied upon to do, but that's a different matter) and getting dirty (another different matter).

[PitskyWitbulls]

Originally Posted by musigenesis

So I think what happens is:

1. Person buys bus with yellow roof
2. Person paints roof with Tropi-Cool
3. Person notices immediate drop in temperature
4. Person swears by Henry's forevermore

The Bussy McBusFace bus started with a white roof.

[EastCoastCB]

Originally Posted by PitskyWitbulls

The Bussy McBusFace bus started with a white roof.

The placebo effect is strong, but I'd hate to have a rubbery coating collecting dust and dirt, yellowing and peeling slowly over the years till one year I have to sand all that rubberized stuff off. Paint won't stick to anything silicone so if you tire of it it ALL has to come off to apply a real paint.

[PitskyWitbulls]

Originally Posted by EastCoastCB

The placebo effect is strong, but I'd hate to have a rubbery coating collecting dust and dirt, yellowing and peeling slowly over the years till one year I have to sand all that rubberized stuff off. Paint won't stick to anything silicone so if you tire of it it ALL has to come off to apply a real paint.

Literally meets your requirement for comparison, dismissed as placebo effect. That's enough internet for me tonight.