11-08-2014, 06:33 PM
1972 31' Sovereign
Join Date: Aug 2014
Originally Posted by canoestream
roof vents -- designed into the more economical argosy line was the plastic roof vent (instead of aluminum). The plastic is no doubt quite fragile at this time. I have seen some more economical replacements than inland rv's offering (camping world?) but can't put my hand on it. You might want to have a replacement in hand before you start messing with this. It is okay if the vent pipe is open to the sky; at most you'll get a teaspoon or two of rain into your black or grey tank.
On removing the roof vent you will see that the actual seal to the black pvc exhaust pipe is some black rubber. The rubber seal's footprint is the same as the roof vent. The replacement vent cover should include a new rubber seal and a new piece of window screen to keep bugs & critters out of your tanks.
The principle source of any water influx would be at interfaces of the rubber seal. Water introduced in the space between the outer and inner skins is very difficult to diagnose when it shows up on the floor quite some distance from the leak. Quite clearly, i would still be most suspect of the design of the battery compartment...
The key to the diagram below is:
Silver = trailer skin
green = caulking (sikaflex 221 is my personal favorite)
blue = your current plastic vent cover
black = black pvc exhaust pipe
red = rubber seal; a friction fit to the pipe does most of the waterproofing but a little sikaflex couldn't hurt
not shown - screen; it should fit loosely between the red and blue, crossing over the top of the stack
i hope you've been reading enough threads to realize that silicone caulk should never ever be used on aluminum -- any bond will fail between silicone and aluminum. I wouldn't trust the rubber to seal at the trailer skin because the vent may overlap a skin lap and rivets; therefore i used the sikaflex. The vent cover is cosmetic only and should have a weep hole in the lowest edge.