Trillium Rotten Floor

[peatle]

So I started to pull out the front benches on the Trillium Jubilee that I mentioned in my first post on this forum yesterday.

I'd already pulled out laminate engineered flooring. Noe there is Vinyl sheet flooring and under that, underlayment ply ( the stuff with the little Xs on ). Then underneath that many and varied scraps of plywood. Different thicknesses and with gaps between and voids between layers, on my god I can'r believe that somebody would do a reno and use up all of their junk.

I finally got down to the fibreglass and the shreds of the original 3/4" ply floor that it had been bonded to. The floor had obviously been rotted out and removed, as far as possible. The parts of it that were under the kitchen and cabinet opposite the kitchen were still sound and had been left in.

My question now is, how do I bond the new 3/4" ply, that I need to put in, to the fibreglass floor. The redundant bolts that held the original floor to the frame members, that are seen in these photos, I can cut out and replace and tighten to suck the ply down to the fibreglass. But will a gun type construction adhesive such as PL or Titebond compensate for the irregular surface under the ply, will it bond to the fibreglass ?

Thanks for any help available,

Peter

ps I think that I have attached the photos but I can't see them in the post and can see no further option to do more with these JPG files. This is a little uncertain method of attaching as far as I can see so far !

[Cam A]

Epoxy works well. Use a slow hardener and wet out both surfaces, then a thin layer of thickened epoxy (fumed silica, for example), drill holes in the plywood to let the epoxy squeeze out, and bolt it down to the frame. If you're not getting squeeze in an area, prop the fibreglass floor up from below until you do. Expensive, but permanent. West systems or other epoxy companies have information on how to use their product. Epoxy by the Leading Epoxy Manufacturer | WEST SYSTEM Epoxy

[peatle]

I checked with my local - Surrey Plasticworks re epoxy and they doubted that I would have enough open time with the epoxy for all the things I'd got to do while installing the new ply floor.

I had done a test with a block of wood and a piece of ply and some PL 400 construction adhesive to attach them to the fibreglass floor. They could not be pulled off by hand after a couple of days and so I plumped for this method of attaching the new ply floor.

I'll post a few pics in subsequent replies. They are of details that are pretty basic to a lot of you pros but might just be a bit informative to anyone that hasn't been in to reno work.

Peter

[peatle]

When the ply was cut to size and laid on top of the fibreglass floor it needed bolting down.

There are three angle iron ( L shaped ) cross members under the floor with holes in for the bolts. I weighted down the ply and drilled up through these holes from below the trailer to ensure that I got the holes exactly where needed.

The ply is fastened down with Carriage ( Coach ) bolts that have a square shank under the head. Hit the head of the bolt with a hammer and this drives the square down into the ply and this stops the bolt from turning when you tighten up the nut. Tighten until the dome of the bolt head is just below the surface of the ply.

[peatle]

I had 3/4" sheathing ply that wasn't Tongued and Grooved so I biscuited the main joint. Biscuits are little oval discs of compressed wood. Matching slots are cut in the edges of the two sheets of ply to be joined and the 'Biscuit' and some glue are inserted in the slots, the edges of the ply are pushed together and then bolted down.

The compressed wood of the biscuit absorbs the water based glue and swells within the slot. This locks it in there and this and the glue bind the edges of the ply together.

This might be a bit of overkill in this situation seeing as how the ply is not over any voids as in the case of spanning between floor joists. I did however want to try and avoid the squeeky floor that this trailer had when I got it. This had resulted from miscellaneous mismatched scraps of plywood over and under each other that rubbed together and squeeked when stood upon.

One of the cross members that I was fastening down to was immediately in front of the axle so it wasn't possible to get a socket wrench or impact driver into it to tighten up a nut on the underside as with the other two cross members.

To fasten to this one I used a type of screw that has a drill point on it ( Tek screw ) and this just threads itself right into the steel member. I did drill a pilot hole first that was slightly smaller than the root diameter of the screw.

Make sure to use a screw that is a 1/2" 0r so longer than the total thickness of the materials that you are fastening together. I tried some that were only 1/4" longer and once the drill point was through the steel angle iron the thread couldn't quite bite into it and was forcing the floor up off of the cross member.

[peatle]

Before putting the ply in place I had spread the Pl 400 ( Titebond is another ) by means of a caulking gun. there is a fair amount of open time with this adhesive but try to get you ply in place before the PL starts to 'skin up' for the best bond.

After the floor was bolted down I took the advice of Cam A and put props up under the floor, midway between the cross members, to push the fibreglass up against the adhesive and plywood.

[David Tilston]

That is impressive!

[Roy in TO]

Nice work!

For others researching this rather than using PL400 I might have considered the 3M 4200 Marine filler / adhesive which has a long set time and is intended to bond wood to fiberglass.
Victor Benz used something other than a carriage bolt when he did his floor that has a broader flatter head. (less bumps).

[peatle]

Roy ... thanks for the reply and comments. There's always some product that would probably have done the job better isn't there ? Had I known about this product I might have looked into using it.

The PL product has really worked well and is very easily available to everyone. The test will be in it's longevity due to the flexing it will be subject to in the moving trailer.

As far as the bolts go ..... there is one called an 'Elevator bolt' that is used to bolt the buckets onto the belt of a 'Bucket elevator', It has a perfectly flat head with a square shank below the head also, that beds itself into the rubber of the conveyor belt. This is an industry specific product of course but could be obtained with a little research I feel.

The carriage bolt works perfectly OK as a few extra cranks on the nut ( I actually used an impact driver ) sucks the dome of the head down below the surface of the ply and then the layer of 1/4" underlayment ply on top of it covers it all up.

Peter

[mmeyer]

Originally Posted by Roy in TO

Nice work!

For others researching this rather than using PL400 I might have considered the 3M 4200 Marine filler / adhesive which has a long set time and is intended to bond wood to fiberglass.
Victor Benz used something other than a carriage bolt when he did his floor that has a broader flatter head. (less bumps).

They are called elevator bolts.
Michael J.

[Harvey9]

Looks good, those PL products work great.

Harvey