Soft Spot Question(s)

[JanetSanCarlos]

It does recess further if I step on it, which is why I thought I should see what is under there. It's weird, the plywood underneath seems firm when I poke holes through the foam. I am so curious!

Thanks

[silverloaf]

Janet-

The lower layer of plywood is only 1/4" thick. Also, the steel cross-members supporting the floor underneath have a wide span between them, typically 24"-28".

As you peel back the top layer of plywood, you should find 1-1/2" square pieces of wood running across the trailer. These define the location of the steel cross-members.

The stiffness of the overall floor comes from the combination of two layers of plywood and a full thickness of foam board. In our trailer, all three are glued together. Individually, they are weak; together, they are strong.

You can stiffen the lower plywood with the wood hardener mentioned earlier. When ready to install new foam board, I used an adhesive similar to below on both sides of the foam board.

https://www.homedepot.com/p/Loctite-PL3 ... /202020476

[JanetSanCarlos]

Thanks Bob! Good info. I did see one of those cross pieces of wood and wondered what it was for. I'm sure there will more pictures this weekend as I scrape out the foam.

[JanetSanCarlos]

Well, I think the mystery is finally solved. Now I just don't know how to get to it to fix it. Today I was able to cut and scrape away some of the foam board. The plywood underneath was in good shape...it just isn't connected to anything!!!

As you can see from the photos the plywood just ends and isn't attached to the piece of wood above it. And there is no plywood or foam on the other side, although the flooring on that side is solid. You can see in the photo that there is a gap until you reach metal. That is about 6 inches away. I assume that is a cross beam.

So, now after all this, do I have to jack up the trailer, remove a section of the belly pan (which if you remember from the first pictures, looks like a piece was removed in that area at some point in the past) and attach the plywood? I hate to remove anymore of the first layer of plywood, because it is all in good shape.

Help!...again!
Thanks

[Salty]

OMG!
I hate that this happened to you. I don't believe you have a choice now, but to go underneath and remove a section of the pan.

[silverloaf]

Hello Janet-

I can’t see the entire floor. But I have a few suggestions.

Lay a 6ft wide level or straight edge across the floor. Determine whether there are any high or low spots along the plane. In particular, lay the straight edge along the piece of wood shown in your pic (sometimes called a “sleeper”).

2nd, take a sharp awl and attempt to pierce the plywood directly under the sleeper. Does it go through or hit something underneath (like steel)?

My 1st thought is the sleeper or top layer of plywood might have warped or bowed upward. Tell us what you find.

[JanetSanCarlos]

Hi Bob -

I'm not exactly sure what you mean, so here is a picture of the whole floor.

So, where am I supposed to put the straight edge??

Thanks!

[silverloaf]

Janet,

I was looking to find the reason for the gap; whether the lower plywood had somehow dropped or whether the sleeper and top layer of plywood had somehow bowed/warped upward.

I wanted you to put a straight edge across the floor from side to side to see if it was either level, crowned or sagged. Also, I can now see there is no room for a 6ft strait edge.

So far as using the awl under the sleeper, the goal was to verify whether the lower piece of plywood was indeed bearing on a steel cross-member.

So..... If there is a steel cross-member beneath the sleeper, you might be able to suck the sleeper and top layer of plywood down to the cross=member. This can be accomplished using self-tapping, hex-head sheet metal screws through the floor and into the steel.

Finally, you really can't do any serious floor work from underneath. The floor is trapped by the steel cross-members it sits on. Maybe a patch but that's about it.

[JanetSanCarlos]

Hi Bob -

Thanks. That makes more sense. Maybe this was patched sometime in the past? Because when I look through the gap, the metal cross beam is about 6 inches away and there is nothing, except bugs and cobwebs, between the edge of that lower plywood and the cross beam. So, I think from underneath I could attach the plywood to the piece of wood that is running crosswise and then rebuild the foam and top plywood. There would still be a gap, but the floor above the gap is solid. I will try to check today if there is another cross beam under there.

Thanks

[silverloaf]

Janet-
If you are certain there is no steel under the bowed sleeper, I would be inclined to cut it in half. I would put my weight on both sides of the breach, then see whether it drops toward the lower plywood.

I would still probe the lower floor for locations of cross-members. Think of them as joists or trusses supporting a house floor.

BTW- don’t go too deep when probing the floor. You’re looking for something solid. I suspect many a trailer owner has unknowingly “ventilated” a holding tank by going hog wild.