Aluminum in Sandwich Floor

[wayfaringgirl]

I have a 2017 Flagstaff Micro Lite 25BHS that has floor softening in the high traffic path with no water damage. I love my trailer, but I'm pretty ticked off about the floor.

I called the factory and know my trailer has the sandwich floor. There is supposed to be aluminum tubing involved. Can anyone tell me where that tubing is? Is it only around the the outside edge or are there cross members?

I'm trying to figure out what to do to help the situation. Both the factory and my dealer suggested adding more cross supports. With the luan/foam/luan sandwich that seems inadequate.

I've searched the forum and the internet and can't find the specifics on the aluminum involved with the floor and I'd appreciate any information you could provide.

Thanks!

[SeaDog]

That type of floor was used on these rigs to keep the weight down. If you look cargo compartments you should be able to see the square tube aluminum and get an idea of the spacing the way to know for sure is drop the coporlast to expose the underside of the rig.

[Gmoney67]

So i repaired soft spot in my unit with same floor construction the aluminum runs the width of trailer and mine was spaced over 5ft between aluminum supports.

[PenJoe]

We experienced a spongy floor in our Sunseeker. I managed to get the floor blueprint. Sorry I asked! The floor consists of a thin waterproofing underside. A grid of square aluminum tubing is welded in spacing of 24" to 32". Styrofoam is cut to fit in the openings. A layer of 3/8ths OSB tops this and the the lino. The aluminum tubing wall thickness, according to the blueprint, is .045" That is the thickness of three layers of a pop can. Forest River would not warranty a spongy floor except for moisture penetration.

I took old bed frame rails and cut them into a grid pattern. Prior to having them welded into place, I drilled 1/2 inch holes every 4" to a depth of the underside of the OSB. Forcing glue into the holes, then drove dowel rods cut to the depth of the holes. The under surface was then sealed. Following the pattern of the rows of dowel rods, the angle iron bed rails were welded in. The bed rails served as platforms to support the dowels that supported the OSB. It strengthened the floor somewhat, but the material in initial construction precluded substantial strengthening.

[yukongold]

My 2012 TT also has that type floor and after about 5 years developed very bad soft spots in several places. I was afraid to step on one of them in fear that I would end up on the ground below.

I started out by trying to locate cross members in the floor but had no luck finding any.
I ended up basically gutting the trailer. The only things I did not remove was the bed pedestal, the cabinet that held the refrigerator and the power center and the shower/tub. Everything else went - kitchen cabinets, bath cabinet, toilet, dinette, bathroom wall - everything.

I thought that after I removed all of that AND the sheet vinyl I would be able to locate cross members. Wrong. I ended up drilling small holes every inch or so the entire length and width of the TT and did manage to find the floor supports. But there was absolutely no rhyme or reason to their layout. I found several that were less than 12" apart and others that were over 36" apart.

My final solution was to overlay the existing floor with 1/2" 7ply marine grade plywood - with a very generous amount of adhesive - and screw it to the supports I did locate. Then I glued down 7mm SPC (Stone Plastic Composite) rigid laminate flooring over that. After replacing the walls and cabinets, the TT looks better than new and the floor is rock solid. It was a lot of work but, in the end, I am glad I did it.

I have heard that FR no longer uses this type floor except in their very smallest units. To save weight, I suppose. I hope that is true. Shoddy design and construction like this is indefensible and owners do not forget it. If I ever upgrade, questions about floor construction will be at the top of my list.

[Bob2019]

Here is another twist to fix a TT floor that may not work depending upon your floor construction. Had a unit (as a newby) that the floor was rotted and even couch legs fell through the floor. I removed the vinyl and carpeting and cut out the rotted spots with a circular saw. Then went under the trailer and put several large sheets of new treated plywood supported either going to a center beam or the frame. Then back inside I cut pieces of plywood to fill-in the circular cuts out of rotted wood that now rests on the new treated plywood under the trailer. Filled in the edges of the top cuts with the rock wood filler and sanded all smooth. Then put down new vinyl. A hell of a job, but was able to fix about 4 wood rotted areas.

This avoided having to gut the walls and cabinets to fix bad floor spots.

[Daniel.mullins4]

I wood try a good stud finder to locate supports.

[Johnfort]

Studs are Aluminum, a stud finder might not work, however a FLIR Infrared gun will if there is an inside/outside temperature differential.