Seat bottom options

[dlang123]

Pulled apart the seats to a pontoon I am working on to try and redo some giant rips in the upholstery, and discovered that the plywood bottoms are rotted and have already attempted to be repaired. I was trying to find something besides plywood that would work.

I see mention of PVC boards, the current wood is 3/4" thick, would PVC board work? It's about 50" long on the longest with a support in the middle. Hold staples?

Anyone know if PVC is what I need, or something else? There are like a million. Any one know places that sell it?

Should I drill holes in it to help with possible drainage/drying of the foam.

 

[Woodonglass]

Welcome to iBoats!
The PVC actually is not very structural. When used as flat decking, it does an adequate job but for your purpose it would not be my recommendation. There's Coosa Board but it's Really Pricey. The problem with your plywood was it was probably not sealed. Ext. Grade Plywood Sealed with Epoxy would do the trick. Not sure how much wood you need but... 1 gallon of epoxy will yield about 2-3 coats on both sides of a 4x8 sheet of plywood. A Gallon of Epoxy with Shipping will be a little less than $90 bucks. Sooo... for a little more than $100 bucks you could build new bases for your seats and coat em with epoxy and they'd last for decades. Use stainless steel staples for your upholstery.