Ideally it’s always best to screw to the timbers with all the layers , it will be a case of alternating the screws on those layers so you don’t end up screwing on top of a screw below . Green deck screws are fine for the marine ply and stainless for the top layer .
You’ll need a good countersink bit , just go easy on the 6mm with it . Can be easy to go too far and open up a hole instead.
One thing I will say about stainless is they can snap the head more than standard screws, so go tight but not ridiculously.
Just another quick one @Chopper if you have a moment? What sort of expansion gap (if any) are you leaving between sheets? On plywood and on the skatelite?
If the metal isn’t thick enough you can see the telltale seam underneath where the metal is laid over where the wood ends. And then with time it actually starts lifting up, which is possibly worse.
Trev at King Ramps uses some flexible skatelite type of stuff at the bottom of ramps. Seems better than metal to me, lasts just as well, less noisy and more flexible for a better join with the floor. I checked my invoices but I can’t see it itemized so I don’t know what it is…anyone know?
Trev got back to me…it’s phenolic birch plywood. I thought it was synthetic because it’s textured but it’s plywood with phenolic resin pressed into the surface. Very durable, weatherproof etc.
Thanks a lot, never heard of that before. Only seems to come in 9mm minimum, guessing they use that for the last bit of the top surface and then plane it down to a sharp edge?
Yeah Trev does that with regular ply too on steeper sections. He gets it to be such a tight fit that it doesn’t need metal and doesn’t seem to wear. Top carpentry skills required
I gotta say though, from memory it does look thinner than 9mm at Spit.
It’s held up really well at Spit. Loads of use obviously, right on the bottom of the mellow bank sections. On steeper bits Trev has just gone straight to the floor with regular ply. The concrete floor at Spit is very flat so it works fine. He’s used tiles of the phenolic ply to make those textured sections where the flat bar and little yellow topped quarter are.
Yeah definitely better than fucking around with specific sized sheet steel and having to route it in .
One 8x4 sheet does so much and to what ever size and thickness you need . Great idea from Trev
Back with another question - is there any reason to not ply the plywood on a transition from the top downwards? Building a shitload of stuff at the moment and we’ve got 2 carpenters helping. They know what they’re doing obviously but have never built ramps. They’re insisting on starting from the coping and going down. I wanted to say no that’s not how it should be done but then realised I don’t actually know why that is. Seems like it would be easier?
