Thomas Roof Sealing Advice

[NovaTRON]

Thomas bus owners, I have this question related to sealing/painting my roof...

My 1995 Thomas roof has the external support rails that run the length of the bus, (I'm not sure if all Thomas buses are built like this, what years, but mine does)
photo 1995 Oshkosh/Thomas roof photo



These rails create a 'channel' in the center of the roof, and what I notice about these rails is that water runs UNDER them and through, and does NOT pool up, like you might expect by just looking at them.

So here's the question, when I go to seal the roof seams and paint the roof (currently I have zero leaks) do I just not seal that rail but seal everything else up, to let the water run under, careful to not let paint-or roof coating, seal the seams of the rails up?

Originally, I thought I would have sealed it all up, water-tight, until I noticed water runs freely under that rail. You obviously don't want water pooling up, then pouring off the roof at the front or back of the bus, right?

To all my fellow Thomas people (others please share thoughts too), How did you address this?

[Sleddgracer]

Originally Posted by NovaTRON

Thomas bus owners, I have this question related to sealing/painting my roof...

My 1995 Thomas roof has the external support rails that run the length of the bus, (I'm not sure if all Thomas buses are built like this, what years, but mine does)
photo 1995 Oshkosh/Thomas roof photo



These rails create a 'channel' in the center of the roof, and what I notice about these rails is that water runs UNDER them and through, and does NOT pool up, like you might expect by just looking at them.

So here's the question, when I go to seal the roof seams and paint the roof (currently I have zero leaks) do I just not seal that rail but seal everything else up, to let the water run under, careful to not let paint-or roof coating, seal the seams of the rails up?

Originally, I thought I would have sealed it all up, water-tight, until I noticed water runs freely under that rail. You obviously don't want water pooling up, then pouring off the roof at the front or back of the bus, right?

To all my fellow Thomas people (others please share thoughts too), How did you address this?

I'm picturing the bottom groove in glass shower doors - they have drains to allow water to flow back into the bathtub- you have the right idea about not blocking the drains

[Watkins]

At some point the school district sealed and painted over the rails on my roof. Not that Ive pulled the ceiling down yet, but I don't have signs of leaks through, or any evidence of pooling on top. I wouldn't worry much. Chances are good that you'll never be parked so perfectly as to prevent water from running off one end or the other.

[Native]

We sealed EVERY seam with EternaBond, then painted with Ames Super-Elastomeric Maximum-Strength Roof-Coating. We did have one little leak in the ceiling at the back due to the rails ... this solved it.

[NovaTRON]

Originally Posted by Watkins

... Chances are good that you'll never be parked so perfectly as to prevent water from running off one end or the other.

I hear you about not parking perfectly level- if the rail is sealed off, then the water will have to channel out of one end, or to a corner- which I then imagine all the water running right to the front door. There is a gutter over the door of course, but that would be less than ideal.

I'd like to keep the intended drain-action intact, but then that also prevents from being able to seal the seam the runs under the rail... I'll have to think about it a bit. Thanks for the input everyone