Undercoating a Palazzo ?

[ky bob]

Hi,
My Palazzo uses plywood covered with plastic panels on each side for the flooring in the basement storage compartments. I have had to replace the flooring in the front passenger side of the my coach.

The flooring wood panel sits down in an angle iron frame, but there was no sealant used during installation to keep water from spraying up to the angle iron frame and seeping into the edge of the plywood and soaking it. This one compartment had a floor that was completely rotten.


I have decided to seal the perimeter of underside of each of the flooring panels with a good silicone caulking.
I also thought about using a rubberized undercoating the completely spray over each of the flooring panels.
Do you think undercoating is a good idea ?
This 3M product is what I was thinking about using

[Kahoona]

Yes. That is the stuff to use alright. I would go one step further and coat the wood with epoxy particularly on the edges. Then caulk if possible and then undercoat.

[ky bob]

I would use this on the flooring that is in place which is in good shape now.

But if I replace any flooring, I would surely coat the sides of the wood.

[iluvuk]

Originally Posted by ky bob

Hi,
My Palazzo uses plywood covered with plastic panels on each side for the flooring in the basement storage compartments. I have had to replace the flooring in the front passenger side of the my coach.

The flooring wood panel sits down in an angle iron frame, but there was no sealant used during installation to keep water from spraying up to the angle iron frame and seeping into the edge of the plywood and soaking it. This one compartment had a floor that was completely rotten.


I have decided to seal the perimeter of underside of each of the flooring panels with a good silicone caulking.
I also thought about using a rubberized undercoating the completely spray over each of the flooring panels.
Do you think undercoating is a good idea ?
This 3M product is what I was thinking about using

Bob,
This seems like nice stuff. I wonder if it is really necessary. On mine (and I think on yours) the wood has a plastic outer layer that is waterproof. It wouldn't need to be sealed. The problem, as you well know, is the gap between the angle iron and the wood edge. I sealed all those with clear silicone. So far so good. I think the only water I am getting in is through small gaps on the door frame weather seal (only when rain is really heavy). That said, if water gets up from underneath, in the angle iron, to the edge of the wood but not up inside, then I wouldn't know it and it could be rotting out the wood without any wetness in the bay to warn me. I really think a hard plastic floor or aluminum is my best bet when I have to replace any.

[RonK]

I am looking at the same problem but with a 2018 Tuscany, and the floor in the wet bay/water tank needs replacement. I need a piece 44"x88" and pricing out HDPE in 1/2" thickness. So far the first price I got is $379 for a 4x8 sheet and $25 for cutting to my dimensions. I just shutter to think about putting ply back in and wonder how long until it rots like the factory job.
Comments from those who have gone this route...

[Robf]

I just replaced part of the floor in my big Bay ( 2016 33.3) I used marine ply wood and was able to reuse the plastic top piece off of the rotted plywood I removed that way it all matches inside the box. I sprayed flex seal under neath and applied heavy amounts along the perimeter where the wood sits on the angle to keep water out. Just went thru several heavy rains on a 3000 mile trip.....Dry as a bone !!! I feel sealing along the angle is very important. That 3m spray is a good idea, I have not used it but bought a can to spray the angle on the remaining areas from underneath.