Removed the black water tank and the dump valve today. More wood rot was also found.
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I started at the dump valve, removing the segmented aluminum trim fairing from the valve outlet.
Spray foam insulation is found once the main piece is removed. This stuff is a time consuming to remove.
Exfoliation is found in the aluminum belly skin. It's going to occur where steel, aluminum, and water (and perhaps a little black water) come together.
Frame rust (scaling) is prevalent in this area and will require attention.
Spray foam insulation removed...
The dump valve must have been replaced at some point. In the picture below, looking into the dump valve outlet: the outlet was notched (hole) at the outer radius of the 90 degree elbow, and a flat piece of white plastic has been glued over the notch (hole). This was done to create clearance for the gray water drain pipe, which exits the trailer pointing straight down. The white area inside the dump valve drain is the glued flat white plastic piece. The gray water drain pipe and the dump valve drain are two separate pipes and are not connected.
Removed the access panel to the shower drain trap while down in this area. This access panel is located on the belly, on the opposite side of the trailer from the dump valve.
Some leakage or condensation has occurred at the trap at some time in the past.
Exfoliation corrosion is found where the belly skin is riveted to the steel frame cross member. This cross member extends across the width of the trailer. The rivets have completely pulled thru the skin across most of the belly along this cross member.
Toilet removal is next.....
With the carpet removed, the toilet flange is visible. I had hoped to reuse the black water tank, but the flange, vent pipe and the dump valve are all glued to the tank. The pedestal floor was installed over the tank before the flange was installed. There's no way to get the tank out without destroying it. The flange and dump valve were broken out, and the vent pipe cut. I hope I can find a suitable replacement tank.
The black water tank is now removed, exposing more rotten subfloor.
The bay is cleaned up. Extensive frame rust is now visible.
An aluminum sheet is installed in the corner. It is removed, and exposes more subfloor rot. The subfloor in the area is still very damp, and has been for a long time.
The frame supporting this area is now visible. The corrosion (rust) damage is extensive.
Subfloor damage appears to extend behind the vanity.
The two pictures below show how the trailer shell is attached to the frame. With the subfloor removed, fasteners can be seen extending from the lower shell aluminum channel to the trailer frame. With the rotten subfloor removed, there is no support for the shell in this area.
That's all for today. Vanity removal is next.