Skate ramp build idea

Hi guys, I know this is unrelated to boat building, but I had this idea to build a skateboarding ramp the following way and I wanted to get your opinion:

Buy local interior grade plywood. Completely encapsulate with 17 oz biaxial fiberglass and epoxy resin to make sure it's completely waterproof. Cover with 1-2" of concrete/steel rebar for the skateboard surface.

The concrete will provide a good and affordable surface for the skateboard. I want to keep the weight down which is why I want to use minimal concrete. This would be for an oceanfront location and I want to avoid having to import marine grade plywood.

What do you guys think? Would it work? I figure I can get away with using interior grade plywood since it will be completely encapsulated in fiberglass, but what do you guys think? Should I still use exterior grade plywood (hard to find in my area) even though it's completely encapsulated in fiberglass?

I'd suggest that the concrete will cause problems. You should have at least 2 inches cover on rebar which would indicate a 4 inch slab. Getting heavy, and still brittle. Possibly grc, possibly other additives in the matrix would be more appropriate.

As an alternative, it is possible to add/sprinkle non slip materials to the epoxy top coat. Boat deck surfaces might incorporate ground glass, though this is gonna be too aggressive for skating. You'd have to select an appropriate powder additive that will allow the right degree of sliding for wheels and skin. This would be easily renewable where and when it wears out.

I'd be tempted to leave the underside/sheltered side surfaces uncoated to allow any moisture that might get in to escape. And try to run to wbp/exterior grade ply. And bear in mind that you can't wrap glass mat tightly round or into sharp corners. It needs a minimum radius. There are other folk on the forum who are much more knowledgable than me and for whom this will be bread and butter - I'm sure you'll get more responses soon.

Bad idea!
Concrete too thin.
Plywood won't support the weight of sufficient concrete.

Thick concrete over earthen forms.
Or
Exterior plywood covered in glass then painted with urathane bedliner.

You should probably join a skateboarding forum. They have good information for skateboard ramps.

Read up on your insurance liabilities. Skate boards, ramps, injuries etc

gonzo said:

You should probably join a skateboarding forum. They have good information for skateboard ramps.

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Thanks I will although I don't think they have as much experience with fiberglass like you amazing people!

Depends on what durability level you want, who will be using it ? I saw a bloke the other day on a skateboard who was 60+, I wouldn't let him through the gate, osteoporosis makes him a risk !

If you are making a concrete structure, there is no need for plywood or fiberglass. Also, the proper design of a ramp is very different from boat design.

I'd look for experience with anti-slip / non-skid coatings for skating.
I imagine thicker plywood is ample strong and 6 oz fiberglass might be enough. And cheaper and easier than concrete.