Trailer deck thickness?

You will need to look at your bracing centers to see if you take off the wood deck you will have enough support bracing when the wheels travel over the new decking.

The wood decking greatly supports the span length since it was design that way. What you may want to do is re-deck with wood, seal the wood with linseed oil both sides, then apply 10ga steel over the wood deck. This assures that the load weight tires will not make bubbles in the steel deck and keeps you for having to add new deck bracing.

Each 4ft x 8ft x 1/4" plate weighs about 330lbs and 10ga weighs about 165lbs for a equal size. Wholesale flat plate is about $.85/lb, with diamond plate higher.

I have 10ga smooth decking on my trailer but I also don't have ice or snow to deal with. A wood deck just won't last in AZ as the summer heat eats the wood very fast.

T_Bone

Sometimes it's cost effective to scrap/sell what you've got and build new. Then you have a trailer that will hold up for years without repair unless it gets some damage.

I would bet the frame looks just like the deck.

Buck bought some GN trailer plans from Northern Tool for $30? that he was impressed with. I've never seen the plans.

A new 2000lb 18ft x 8ft with 4ft dovetail trailer with "I" beam frame and steel decked, 6k tandum electric brake alxes would cost about, $2800 in materials for 12k GVWR.

Used in business it would last about 20yrs if you take care of it, so about $140yr for ownership.

T_Bone

If youcan't do the calculations, in a prof engineer who should be able to do it in 15 minutes.