New Decking
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Unattended leaks from end the cap
seams, one taillight fixture, one backup light, and deteriorated access door
gaskets laid waste to the bathroom floor over time. This composite image was taken just after
most of the rotted decking was removed.
The inset image shows damage where the battery is normally mounted. |
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The aft-most 4X8 sheet of 5/8”
decking was removed to cover the bulk of the repair while the damage in the
battery area was cut back to good wood. |
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Severe aft decking damage can be
addressed two different ways. One
method, known as the clamshell,
involves removing all exterior metal at the frame/decking line, spreading the
back of the trailer open, and sliding in a complete section of new decking. Due to the placement of the battery
area damage & my general uneasiness with the first method, I chose to do
a two-piece repair placing the seam over the main frame C-channel. The seam was later fortified with
glassed-in steel dowels. |
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Since there was not enough good wood
left to act as a template, a large sheet of cardboard was repeatedly trimmed
until a good decking prototype was developed. |
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In spite of chamfering the edges of
the new decking & covering them with duct tape (to both seal & cut
down friction), a mini clamshell technique had to be employed since the shell
was not happy about its current lack of structural support. Here you can see a bottle jack
supporting the shell at a rib while concrete blocks force the bumper (frame)
down. |
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The next hurdle was figuring out what
size the plumbing cut-outs were supposed to be around the dump valve. I sent this picture out to everyone I could
think of who might be able to help. A
special thanks goes out to Sneakinup & Overlander64 at the forums for
their help. |
Elevator
bolts hold the new decking in place. The seam between the old & new
decking was scabbed from underneath with decking, polyurethane glue, and
screws. There is
quite a debate as to what kind of product makes the most suitable
decking. I saw my reasonable decking
replacement materials possibilities as either plywood or OSB. Plywood subchoices
consisted of interior, exterior, treated, or marine grade. While I could bore you with details, the
bottom line is that I had more confidence that OSB would last considerably
longer with less damage if an undetected leak were to occur simply because of
the manufacturing process. Basically,
since all the pieces of wood that make up OSB are sitting in a big pot of
waterproof glue prior to being formed into sheets, the individual wood pieces
are each sealed. Not the case with
plywood. Treated
plywood was not a consideration to me because most treatments are to keep
insects from destroying the wood, and do not do much in the way of preventing
rot. It needs to be dry when before
installation, and the sheets I saw for sale were wet, buckled messes. In the
"from experience" category, a friend built a house several years
ago. Needing one more sheet of OSB to
finish sheathing a wall, he remembered a sheet he had left outside a year
prior to cover something. Retrieving
it, only sun damage was noted, and he was able to use the entire sheet. From my own experience, I knew that plywood
would NOT have fared as well. Then I
read that the Airstream factory now uses OSB in the construction of new
Airstreams. The final
kicker was that the home improvement store carried the 5/8 inch thickness
that I needed. So far, so good; I have
no qualms about using OSB. |