Synthetic deck material is not designed for that application. I do a fair amount of deck work and usually try for a max of 16" on center or less if the math works out to keep Trex, Azek Deck, etc. from flexing.

Plain old pressure treated SYP 2X is just fine for your trailer deck. Treat it every few years with Sikkens, etc. to preserve it and the lifespan will double.

RT

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