Adding subfloor to 189FBS?

[Adirondick]

From underneath the trailer, the floor of the 189FBS appears to be a single sheet of plywood, painted back. There is some spring to the floor in at least one place inside the trailer, which reinforces my thought that the floor is thin. I'm interested in strengthening the floor by adding another layer of plywood, section by section. I would use pressure treated plywood and would use construction glue and short screws to hold the panels in place. Then I would cross my fingers as we travel that none of the "tiles" would come off our little space shuttle as we lurch and bounce along the road. Is this a cockeyed idea? I'm also interested in adding a layer of foil-faced foam insulation between the existing floor and the new plywood. Has anyone done anything like this? Yes, there is a weight increment to all this, which is not so good.

[keyser soze]

You will certainly stiffen the floor by adding another layer of plywood, but the foam insulation between the layers will not provide a good bonding surface. If I were undertaking this task, I would definitly use Liquid Nails or similar bonding agent. In order to ensure a strong bond, I would make sure I cleaned the surface of the existing flooring very good, maybe even sand it a bit to give the bond a good surface, doing that you will never be able to remove the sections you add. As far as weight is concerned, keep in mind a 4x8 sheet of plywood typically weighs 25lbs per 1/4 inch of thinkness. I would think 3/8 to 1/2 would be excellant for your application. Remember to paint the added wood, making sure to get the edges liberally with a high quality exterior paint to seal the wood. Another idea you may look into would be to adding 2"x3" joists accross the span you want to stiffen. Spaced every 12-16 inches, then cut foam board to fit between them, then seal it with paint and a thick plastic sheet for weather proofing.

[chupp21]

I think you would only need to reinforce the floor locally where you notice the bowing. You would not need to reinforce under the dinette, bed, cabinets etc. You could accomplish this by screwing steel L or U channel to the underside of the trailer floor. Make sure your screws do not go all the way through the floor. A bead of liquid nails would help bond the channel to the wood as well. I am also thinking of installing some foam panels for insulation. Either styrofoam or the foil backed stuff. My thought would be to find some wood screws that pass through the foam and into but not through the floor. I would install it with some big washers to support the foam. This should provide a lightweight fix.
Another thing I noticed is that I always find water on the bathroom floor after showering and they did not do a good job of sealing the bathroom. Eventually the water will find it's way into the wood and rot the floor. This would be extremely difficult to fix. I bought a tube of clear silicon and sealed the shower pan, cabinet and toilet to the floor. I then dry the floor after showers. It's also a good idea to look for leaks in the sink drains and water lines as well.