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Generator exhaust roof water leak - davidbrady - 07-19-2013 18:35

I'm still in Pennsylvania and we've been having torrential downpours, sheets of rain. These storms are a great test of the Brady Slide Seal. I'm quick with my flashlight to spot any interior dampness that may have breached the seal. The good news is, the slide seal is weather tight! The bad news is I found a steady stream of water coming down my genny roof exhaust. As many of you know the genny roof exhaust is encased in a 4" stainless steel pipe as it routes it's way thru the bus interior. The stainless is wrapped with a reflective insulation. Water is streaming down outside surface of the insulation wrap. I have yet to climb on the roof to look around, too much lightening, but I think it's designed so that rain can run down the void between the genny exhaust and the stainless steel outer pipe. This doesn't seem to be my problem. My leak seams to be on the outside face of the stainless steel protective piping. Have any of you experienced genny exhaust water leaks of this type? What should I check for? Are roof caps available where the exhaust protrudes thru the roof and seals onto the roof surface?


RE: Generator exhaust roof water leak - cmillsap - 07-19-2013 22:52

(07-19-2013 18:35)davidmbrady Wrote:  I'm still in Pennsylvania and we've been having torrential downpours, sheets of rain. These storms are a great test of the Brady Slide Seal. I'm quick with my flashlight to spot any interior dampness that may have breached the seal. The good news is, the slide seal is weather tight! The bad news is I found a steady stream of water coming down my genny roof exhaust. As many of you know the genny roof exhaust is encased in a 4" stainless steel pipe as it routes it's way thru the bus interior. The stainless is wrapped with a reflective insulation. Water is streaming down outside surface of the insulation wrapping. I have yet to climb on the roof to look around, too much lightening, but I thing it's designed so that rain can run down the void between the genny exhaust and the stainless steel outer pipe. This doesn't seem to be my problem. My leak seams to be on the outside face of the stainless steel protective piping. Have any of you experienced genny exhaust water leaks of this type? What should I check for? Are roof caps available where the exhaust protrudes thru the roof and seals onto the roof surface?

David,

I'm not familiar with whether the 4" stainless protrudes through the roof or not. If it does, it's probabaly the sealant around it at the roofline.

I will go look at how my genny exhaust exits through the roof tomorrow and we can compare notes. I wish I had checked WAGU a little earlier as I was on my bus's roof today replacing the fart fan.

Don't go on the roof if it is lightening!!


Chuck


RE: Generator exhaust roof water leak - davidbrady - 07-19-2013 23:08

Well the lightning stopped so I had a chance to get on the roof. The leak is plainly visible. The plastic (pvc) nacelle that encases the genny exhaust pipe distorted and lifted from the roof of the bus. A quick bead of urethane solves the problem but the nacelle is cracked and should be replaced. Anyone know of a supplier for this piece? It can be repaired with urethane, but it'd be interesting to see if a replacement is available. Maybe I'll get on the phone with my local school bus franchise to see about a vendor.


RE: Generator exhaust roof water leak - gondolaguy - 07-20-2013 08:53

(07-19-2013 23:08)davidmbrady Wrote:  Well the lightning stopped so I had a chance to get on the roof. The leak is plainly visible. The plastic (pvc) nacelle that encases the genny exhaust pipe distorted and lifted from the roof of the bus. A quick bead of urethane solves the problem but the nacelle is cracked and should be replaced. Anyone know of a supplier for this piece? It can be repaired with urethane, but it'd be interesting to see if a replacement is available. Maybe I'll get on the phone with my local school bus franchise to see about a vendor.

Great post, glad you found it! While up there and buying parts, consider replacing the plastic cover on the pop-up fan. Mine literally shrunk up causing a tiny crack next to the screw that leaked water, but took me a few trips on top to locate.


RE: Generator exhaust roof water leak - cmillsap - 07-21-2013 00:52

(07-19-2013 23:08)davidmbrady Wrote:  Well the lightning stopped so I had a chance to get on the roof. The leak is plainly visible. The plastic (pvc) nacelle that encases the genny exhaust pipe distorted and lifted from the roof of the bus. A quick bead of urethane solves the problem but the nacelle is cracked and should be replaced. Anyone know of a supplier for this piece? It can be repaired with urethane, but it'd be interesting to see if a replacement is available. Maybe I'll get on the phone with my local school bus franchise to see about a vendor.

David, I thought that piece was metal...


RE: Generator exhaust roof water leak - davidbrady - 07-21-2013 13:42

Thanks Chuck,

Here's a couple pics of mine. [attachment=677] [attachment=678] The bright white in the photo is some makeshift plumbers putty that I globbed on to temporarily stop the leak. My guess is that BB used this piece on all Wanderlodges with roof exiting exhausts. This coming week I'll make some phone calls to see about a replacement. Now I need to climb back on the roof to see about a manufacturer or a part number that might be stamped on the nacelle. Mine's plastic - yours may be metal.


RE: Generator exhaust roof water leak - cmillsap - 07-21-2013 14:42

(07-21-2013 13:42)davidmbrady Wrote:  Thanks Chuck,

Here's a couple pics of mine. The bright white in the photo is some makeshift plumbers putty that I globbed on to temporarily stop the leak. My guess is that BB used this piece on all Wanderlodges with roof exiting exhausts. This coming week I'll make some phone calls to see about a replacement. Now I need to climb back on the roof to see about a manufacturer or a part number that might be stamped on the nacelle. Mine's plastic - yours may be metal.

David,

I could not find a part # on mine. There may be one on the underneath side? BTW, after 45 days of sitting outside at Redlands, the bus was pretty dirty. I had it washed yesterday and 1 hour afterwards it started to rain here. It hasn't rained here in months!!

Chuck


RE: Generator exhaust roof water leak - pgchin - 07-23-2013 10:58

David,
I climbed up on the roof yesterday to take a peak. My apologies, I cannot add more than you or Chuck. NO part numbers anywhere I could see, and I brought my glasses with me! Mine is exactly like yours and Chucks. Mine is some kind of plastic / composite as there are hairline cracks by 2 of the screw holes.............. Doesn't leak now but we know how that goes!Big Grin Monsoons are great roof checkers!Wink Three weeks ago, the rain was so bad in Tallahassee I need a "bucket"!Rolleyes Turned out to be that silly triangle "cap" over the loudspeaker wire! Rain poured off the antenna riggng right down that wire hole!
Anyone who says their roof doesn't leak, just hasn't found the leak yet!Tongue Tee......Hee! Have a safe trip!!!!!!


RE: Generator exhaust roof water leak - wtwtw - 08-15-2013 21:32

I know its a little old but I am new here so I thought I would throw in my 2 cents. They make roof boots for plumbing stacks like this one.
http://www.ebay.com/itm/Metal-Roofing-Pipe-Boot-Flashing-3-HD-1-4-5-Round-Terracotta-DK3RTC-/171092889178?pt=LH_DefaultDomain_0&hash=item27d5ee4e5a


They also make them in silicone. I do not know how they will handle the heat from the exhaust but silicone usually does pretty good.
Here is a silicone one.
http://www.ebay.com/itm/Metal-Roofing-Pipe-Boot-Flashing-3-1-4-4-ROUND-SILICONE-GRAY-MF3RSG-/171078685241?pt=LH_DefaultDomain_0&hash=item27d5159239


If cut properly they seal quite well


RE: Generator exhaust roof water leak - davidbrady - 08-15-2013 22:32

Thanks Bill,

Those boots are great pieces which I'll file away for future reference. In my case the PVC exhaust surround warped slightly and lifted from the bus roof. A five inch bead of Sikaflex 221 did the trick. Thanks for your effort and I very much appreciate the post!