Since it took months and considerable effort, I thought I'd pass along
the source of some extremely difficult leaks I've recently cured. After
caulking everything up river of a leak that showed up at the very back
of our trailer, on top of a piece of flashing that extends out the back
end on top of the bumper tool box and frame but below the plywood
subfloor, I discovered that the water was getting in through the light
fixtures, by sneaking past the lenses, accumulating in the fixture, and
getting in to the walls through the wire holes that penetrate the
fixture. It took a water test to discover this source.
I solved the leak by fabricating gaskets for the lenses. These are
made from Grace & Co. Ice and Water Shield- a heavy gage self adhesive
rubber membrane used by the roofing trade. (while Ice and Water Shield
is available only in large roles, an identical product is sold at
building centers in narrow strips, used to seal window nailing flanges
to the walls of houses. This is handy stuff and it adheres
tenatiously). I cut the gaskets out of the material, using the lenses
as templates, leaving a 1/4" wide strip inside the perimeter of the
lens where it contacts the light fixture. I adhered the material to the
lenses and replaced the lenses. Woila!
Before the water testing process, I had removed a small section of
badly rotted subfloor in one of the rear corners, in preparation for
patching in a new piece. While water testing, looking in to this hole
we discovered a veritable torrent of water coming in on to the top of
the belly skin. Upon looking closely at the construction, it seems as
though Airstream in their infinite wisdom ran the belly skin out to
form the bottom of the bumper tool box. And they didn't seal it in any
way what so ever. Since the tool box is far from water proof (it has
holes in the bottom for water to drain out...) this is a major source
of water getting in to the rear end of the trailer. I fixed it with a
half a tube of Vulkem between the belly skin and frame in the tool box.
Anyone with a trailer of similar vintage might do well to check on
these two areas and attend to them. Leaks here are difficult to detect
until much damage is done.
Best,
Chris Koehn
1979 @ 31' Int'l