I bought a 1998 used trailer on eBay, which was listed as "good floor".  Well, not only does it NOT have a GOOD floor, but it is a completely unsafe floor.  When I picked it up, they had put plywood down(and screwed it down), supposedly because one board had a dip in it, so the floor wasn't completely level.  I knew the plywood was a bad sign, but I had already bought it.  I was furious when I got home and got the wood up to find that there were boards with actual holes and that you could pick the wood out with your fingers!  When I e-mailed these folks about how badly misrepresented the trailer was, they still insisted the floor was GOOD!  I told them I wouldn't load a horse to stand in the parking lot in it!

Anyway, so now I have my first horse trailer and I have to replace the floor.  With a trailer that old, it probably wouldn't have been a bad idea even if it looked good.  From checking underneath the trailer, it appears all the croos bars are in good shape.  surface rust, but amazingly no flaking.  Seems just surface.  I plan to clean those up and paint them with a good rust resistant paint, once I get the floor out.  Any suggestions on a good treatment for them?

I have seen people say to use pressure treated wood for the floor and others say pressure treated wood will corrode the metal.  Which way should I go?  My Superintendent at work says no pressure treated, just get regular wood and treat well with deck sealant.  He, also, checked around and said that I wouldn't be able to find oak boards finished and sanded and cut uniformly, like pine and if I did it would be cost prohibitive.  He suggested using yellow pine(not white pine) and said that was common for horse trailers.  I have not gotten out to a real lumber yard to check on finding that.  I can't really do anything until after the holidays, anyway.  Is this a good choice for flooring?

I think with a little rehab work, this will be a great trailer.  It is really tall and nice and wide for my really tall and nice and wide warmbloods.

Luckys

There are several species of wood that will work well on your trailer floor. I would try to contact a custom sawyer who saws logs into rough cut lumber. On the whole eastern part of the states are wonderful hardwood forests that provide an assortment of species that will work well for your application. Rough cut lumber is much less expensive than the dimensional lumber found at the big box stores, and is available in many species depending on your location.

I would consider white or red oak, white ash, locust, maple and popular as good candidates for flooring. Untreated southern yellow pine will work, but generally is less available in rough cut lengths. Most of these species are currently available in less than "clear or select cabinet grades" at prices less than $3.00/ board foot. Small tight knots are perfectly acceptable, do not accept any boards with shakes. Buy them in 7 quarter thickness and have them planed to 6 quarter if cut on a band saw. Try to pick out the quarter sawn stock instead of the slab cuts. They will be stronger and have less cupping.

If they are covered with rubber mats and the trailer is enclosed, the flooring will last several decades. We recently sold our 1992 trailer and the OEM popular flooring was absolutely like new.

On your trailer frame, after you clean off all the rust, by sandblasting or wire brush, use a rust "converter" (phosphoric acid) before you apply the primer. This will insure the rust is stopped before you paint. Use an epoxy automotive primer/sealer and a good name brand undercarriage paint, which is also available from your automotive parts store.

If you spend a little time now, and do a quality job, your trailer will last as long as you need it and actually will increase in value with your added improvements.

BOL  Gard