Rusty floor... to patch or not?

[Brewerbob]

So, I took out a 12"x24" section directly behind the drivers seat and replaced it with fresh steel. I still need to decide what I'm going to do with the heater hoses. I suppose I need to get out there with some buckets and at least run the hoses along the frame rail under the bus.

Anywho, I still have some random holes in the flooring. For scale, I put a nickel next to them. I have another 12"x24" piece of 14 gauge. I've got a couple of pieces of 16 gauge as well. Should I cut out the rusty spots and patch it? They worth the effort or just rust treat them and cover with spray foam? If I patch them, how big should the patches be? I don't (currently) have the metal to patch from cross brace to cross brace.

I'm going to give spray foam a try as a way to seal all of the nail and bolt holes. Give it a thin spray from a DYI kit and then foam board on top of that before ply and final flooring.

[Njsurf73]

If it's solid. Treat it, paint it and cover it. If it's flimsy, that would be a concern for the future.

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[Brewerbob]

Originally Posted by Njsurf73

If it's solid. Treat it, paint it and cover it. If it's flimsy, that would be a concern for the future.

I was afraid of an answer like that!! There's a spot or two that moves when walking around. Those spots are solid (no holes) and even the surface rust isn't bad/none at all. I suppose I need an extra body. Someone standing where the soft spot is and me underneath to see where/what's going on.

[Njsurf73]

You could put a drill through and look from the bottom... just get an eye on the area first round make sure you aren't going to hit something from above. You may have a rotted cross beam (if that's what it's called) if not, foam and ply will seriously stiffen everything up. To the point you shouldn't see any deflection even with a big hole.

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[Brewerbob]

Originally Posted by Njsurf73

You could put a drill through and look from the bottom... just get an eye on the area first round make sure you aren't going to hit something from above. You may have a rotted cross beam (if that's what it's called) if not, foam and ply will seriously stiffen everything up. To the point you shouldn't see any deflection even with a big hole.

Normally I would agree with the exploratory hole but after yesterday, I'm going to have to strongly disagree. Go back to the patch pic... the mar in the center. That was me drilling a hole so I could weld to the cross member. I missed. So I went under the bus and checked to see how far. The hole was just aft of the beam. I drilled another and missed again!! I quit and filled in the holes.

I didn't use a tape measure but I was using a straight edge from where I could see the beam and to a spot weld mark. How the hell I missed twice, I've no idea. Flashlight from underneath is the only way to go.

[Iheartbus]

Non-expert opinion, if the hole is caused by rust, cut it and weld it if the hole is really big. If not, the foam ply would work. I'm super scared of rust, because unless you ensure 100% certainty there is NO WAY moisture will get to it...it's gonna grow. Better to do it now than later.

[EastCoastCB]

I'd treat it heavily with ospho, and if its flimsy I'd just rivet down a panel right over the part that's weak.

[fabrini]

I patched my holes with pieces of galvanized duct repair pieces. I put a bead of silicone around the hole, put a bead of adhesive a few inches away from the silicone, then put a patch down. I self-tapped in a screw at each corner of the patch. Once a day passed, so the silicone and adhesive could cure, I put a thick coat of Kilz oil based primer over it all just for good measure. (I let that dry for 24 hours as well.) Then I put down 3 new pieces of 11 gauge steel plates on top of it all. I used PL200 and a few self-tappers to hold all that down. It's secure now and pretty stout. I figured new steel plates secured over the weakened floor would be better than simply using patches since the steel plates will displace weight over the entire area. Hopefully it will be strong enough to hold my 4 wheeler since that is what will be sitting in that area. (I treated the rusted areas before I put the primer on it with Rustoleum Rust Reformer.)

[CCurran88]

I have a few spots when I walk around my bare metal floor that flex a lot more than the rest of the floor. A quick peek under the bus shows that particular area was spot-welded to the frame, but has broken loose. I'm hoping (once I get to the repair the floor part of my schedule) that I can just re-spot weld it. I'll be cutting out around the rest of the rusty holes and replacing those with steel patches, then also welding over the bolt holes. I received a MIG/Flux wire welder from my husband for Valentine's day and will be learning the art. A great bonding experience. Some would worry, but we've been married for 33 1/2 years. His first test of the marriage was teaching me to drive a stick-shift, and we survived that, so I think we'll get through this as well.

[Brewerbob]

Originally Posted by fabrini

I patched my holes with pieces of galvanized duct repair pieces. I put a bead of silicone around the hole, put a bead of adhesive a few inches away from the silicone, then put a patch down. I self-tapped in a screw at each corner of the patch. Once a day passed, so the silicone and adhesive could cure, I put a thick coat of Kilz oil based primer over it all just for good measure. (I let that dry for 24 hours as well.) Then I put down 3 new pieces of 11 gauge steel plates on top of it all. I used PL200 and a few self-tappers to hold all that down. It's secure now and pretty stout. I figured new steel plates secured over the weakened floor would be better than simply using patches since the steel plates will displace weight over the entire area. Hopefully it will be strong enough to hold my 4 wheeler since that is what will be sitting in that area. (I treated the rusted areas before I put the primer on it with Rustoleum Rust Reformer.)

Double skin without spacers would worry me. Sand and vibrations = sand paper. More time, money, effort and probably overkill but I would have pulled up the original sheet metal and replaced with a single layer of whatever gauge is needed to support an ATV. At the very least drill holes every 6"~8" and do a plug weld.