I have a utility trailer that is not but about 15 years old but the floor boards have rotted away. I boards are not bolted on but held in place by plates that are welded on. I want to do this right and replace them with something that will last. I have read that the new treated lumber will react with most metals. I’m unsure what type of metal the trailer is made of. Is there a treated lumber I can use? If not what type of wood would be best and should it be painted like original or some other type of treatment applied? should there be gaps between the boards? Originally there was not. If gaps are need any suggestions on how since the boards aren’t bolted down.

I’ve not heard about that reaction. I put ground contact treated boards on my atv trailer 2 years ago and not noticed any ill effects. My utility trailers either have expanded metal or diamond plate decks. I helped a friend replace boards that were secured like yours, I suppose, on one of his trailers a few years ago. We jacked the boards up in the middle until they became short enough to escape the angle iron which held them down, then reversed the process (with more jacks) to bend the new boards and install them. Painting is optional IMHO, I like the bare wood personally. Gaps are not required.

I suggest you cut the boards to size, then treat sides, edges and ends with boiled linseed oil before installing.

Need to do the same thing. I loaded my Harley onto the trailer to take it to be serviced. The rear wheel fell through the base boards on the trailer when I loaded the bike on. Luckily it didn’t do any damage to the bike and I was able to free the bike on my own. I used a come along winch to pull the bike forward and out of the hole. I just avoid the hole now but need to dedicate a moment in time in the future to fixing it. I was thinking of using diamond plate myself. It comes in aluminum and steel. I’d need to take all the wood out first to see how I could make it secure when it’s mounted. The good thing about a wood base is there is good traction and it’s fairly light. I would think a good grade of 3/4″ exterior plywood would work well too. Redwood or cedar would probably be a good choice too as they would resist rot, just avoid grades with knots as the knots would effect the strength. I’d be interested in reading the posts on this subject if anyone has done this.

Redwood and Cedar have very little strength. However you can use ACQ on a steel framed trailer but you will be well advised to coat the steel portions that will be in contact with the lumber. A coat of fiber roof coat will keep the boards from coming in contact with the steel. Apply the roof coat and allow to dry or set for several days before installing the wood. Use plated screws or bolts that are designed for ACQ lumber. Aluminum over steel is a poor choice as electrolysis will deteriorate the aluminum over time. ACQ cannot be applied to an aluminum frame for the same reason. The high concentration of copper in the ACQ will react with the aluminum. You may be able to find scraps of diamond tread stainless but hang on to your wallet.

We’ve played this games many, many times! ugh, lots of work! We cut a piece out of the top of the welded plate… usually 10″ is plenty..just on one end. Then remove the old, by sliding them to the “hole” lifting out that end, the other end will fall. Return new planks the same way.. in reverse! :-) Fit into the “closed” side first (the one you didn’t remove metal from) then lift other end and drop into open spot (where you removed the metal) then slide to the edges, the last board will set in “the open spot”. Then weld the piece of metal back in place.

On the flatbeds I like to leave a gap between boards, but you’ll either need to bolt them in, or use spacers in those metal channels to keep them from sliding. Why? Because usually the rot comes from rain not quickly draining off the surface. I also always unhook and keep cranking the jack until there is a good pitch to the trailer to help the water run off faster.

Your trailer is likely steel, you’d know if you paid the enormous amount extra for aluminum. I do treat with rustoleum, then paint with rustoleum. We don’t paint the wood, just the steel.

The first time we did this it took a weekend, we’re now down to about 4 hours for the labor part. The finish coat of paint of course takes more hours to dry before the trailer is usable again.

Most trailers – the angle iron pieces on the back of the trailer that holds the board on are spot welded on so you just have to take an angle grinder and hit those few spots. Install boards and spot weld again. The bolts in the middle are obvious replacement. Some may require grinding off if to rusted. Have fun – it is a pain and time consuming no matter.

I would suggest green oak, and bend them to put them in, and put them in tight, as they dry they will shrink, Have an oak bed on my trailer and it is about 22 years old and still in decent shape.