Ceiling Vent Fan Leak Caused By Cracked Vinyl Base

[T and C]

This may seem like a dumb question, but I am no handyman and I am reluctant to try to pull the Fantastic Fan out completely.

If the cracks were in the base, why wouldn't resealing the outside part of the fan assembly solve the problem. Seems to me that if water can't enter, it would never reach the cracks in the base, if there are any.

Tom

[RLDeLay]

Tom, this is the approach that I took and it stopped the leak. It has held for two years. Just to be safe I plan to "re-caulk" this spring.

[Steppy]

Properly installed vents should never leak. I could have gooped on yet more caulk on the side and top of the vinyl base to try to stop the leak. But then the leak can reoccur when that caulk shrinks or cracks in the future. My purpose was to install the unit correctly, once for all, which I found the factory didn't do. It's not that onerous of a task really. I don't ever expect to ever have any leaks again around that vent. And I certainly don't consider myself to be a handyman. Believe me, if I can do it, anyone can.
Good luck in whatever you choose to do.

[Mrfixit]

Just completed removal and re-bedding of the vent fan combo. I agree with Steppy that a properly installed vent should never leak if done right the first time. I found the same things others have in this thread: no pre-drilling of the plastic frame under the flange, not enough caulk to provide a continuous barrier to water, and in my case, the whole assembly mounted off-center from the cutout in the roof.
This caused at least nine mounting screws to miss the aluminum skin completely. Made a new frame from StarBoard material from West Marine, but made it 1/4" thick instead of the original 3/4". Couldn't see a good reason why they did that, unless that's the material they had on hand at the factory. I used 3M 4000UV urethane adhesive sealant between the roof and frame, and a good quality white silicone sealant between the frame and fan flange. The 3M 4000UV has good UV qualities and won't yellow like 5200 or 4200.

Water test tomorrow ...

[scrubjaysnest]

Originally Posted by Mrfixit

Just completed removal and re-bedding of the vent fan combo. I agree with Steppy that a properly installed vent should never leak if done right the first time. I found the same things others have in this thread: no pre-drilling of the plastic frame under the flange, not enough caulk to provide a continuous barrier to water, and in my case, the whole assembly mounted off-center from the cutout in the roof.
This caused at least nine mounting screws to miss the aluminum skin completely. Made a new frame from StarBoard material from West Marine, but made it 1/4" thick instead of the original 3/4". Couldn't see a good reason why they did that, unless that's the material they had on hand at the factory. I used 3M 4000UV urethane adhesive sealant between the roof and frame, and a good quality white silicone sealant between the frame and fan flange. The 3M 4000UV has good UV qualities and won't yellow like 5200 or 4200.

Water test tomorrow ...

Unfortunately this is a RV industry problem, not just TM. We had a similar problem with the bathroom sky light on our Outback. It has the rubber roofing and needed angle bracing added so there was something to screw into.

[Mrfixit]

Originally Posted by scrubjaysnest

Unfortunately this is a RV industry problem, not just TM. We had a similar problem with the bathroom sky light on our Outback. It has the rubber roofing and needed angle bracing added so there was something to screw into.

My experience from the boatbuilding industry is that there are few actual boaters working on the assembly line. They may not know the problems associated with incorrect bedding or caulking of a hatch or skylight. This may also be true of the RV industry. We knew from experience that the prudent yacht buyer would never purchase a boat if the hull or deck was laid up (fiberglassed) on a Monday or Friday!

In our new to us 2002 3023 we have a roof leak. So today we removed the vents and are removing all the old caulking. The wood between the two sheets of aluminium is rotten to the point of disintegration. The top boards attached to the vent hoods seam to be ok. There is also a dip in the aluminium between the 2nd vent and the Ac unit, is that suppose to be there? If any of you have any suggestions to help us fix our leak issue please respond.