[A/S] Re: Hi, I'm new here

["Chris Koehn" <timberguides@xxxxxxxxx>]

I too discovered some plywood sub-floor rot in a few areas; in my case, 
the rear curb side corner and the opposite front corner. We have a 1979 
31' trailer. I chose to experiment with solutions that do not require 
disassembling the trailer to the extent necessary for complete 
sub-floor replacement.
After I was certain I had cured leaks, I removed badly compromised 
plywood (limited to < a couple of square feet), patched in new pieces 
(3/4" fir 5 ply B-C grade), and treated all plywood with wood hardener. 
I was concerned about the structural connection of the bottom plate 
channel to the sub-floor in a few areas. The channel is simply screwed 
down to the plywood in the original construction, so if there is any 
compromise in the integrity of this connection- be it a rusted screw or 
punky plywood- there could be trouble.
I chose to use a metal "hurricane clip" - one of several commonly used 
metal fasteners in the homebuilding industry at various locations along 
the structural framing to provide a continuous connection path from the 
roof to the foundation. Simpson is perhaps the premier manufacturer of 
these, although there are many others. They are readily available at 
building centers and big boxes. The hurricane clip is an "L" shaped 
piece of galvanized heavy gage sheet metal that is perforated to accept 
fasteners. I used these at each metal stud and one in between, 
fastening the vertical leg to the metal stud and channel (through the 
interior skin) with a coated "hi lo" screw- used for structural 
applications in metal. I attached the horizontal leg to the plywood 
with pan head wood screws. I had one area in which I was uncomfortable 
with the integrity of the plywood at the clip location. I was able to 
install a wood patch under the sub-floor via an access hole cut 
adjacent to the fastener, so that the screws went through the sub-floor 
and in to the (laminated) patch.
Since both of my punky areas were hidden by furniture (bed and gaucho), 
aesthetics were not a concern (there are only 6 lineal feet of wall-to 
floor connection exposed in my trailer..), though the clips are not 
overly conspicuous, at 3" X 3".
I've got 15K miles on the trailer in all kinds of conditions with this 
fix and there is no evidence at all of movement in these locations.

For the record, I strongly suspect that some of the moisture that ends 
up on the sub-floor is condensation, from using the trailer in cool 
weather. It stands to reason that some warm humid interior air will 
find its way in to the wall cavity, where the dew point will cause it 
to condense out. There are no allowances for weeping; if I were to go 
to the trouble of removing the skins and studs from the chassis to 
replace the sub-floor I would certainly install some sort of weep 
system through the channel.

Best,
Chris Koehn
1979 @ 31' Int'l Sovereign
<www.koehnjourney.blogspot.com>