Treatment for PT plywood for outdoor ramp

   / Treatment for PT plywood for outdoor ramp #1  

SmallChange

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Tractor
New Holland WM25 with 200LC front end loader, filled R4 tires 43X16.00-20 and 25X8.50-14 (had a Kubota B6200D with dozer and R1 tires)
I have a wooden equipment ramp on my barn to make up a couple feet between the elevated floor level and outdoor ground level. It used to land in dirt and sink into it, but I paved and so now it lands on asphalt and sticks up. I trimmed the bottom of the ramp, tapering the support timbers as far as I thought I could, but there's about a 5" drop still to be taken care of.

So I figured I could use three thicknesses of 3/4" plywood, glued together, and tapered at the end to minimize the bump at the bottom. I bought and cut the plywood -- it's pressure treated and rated for ground contact, but I do not think that will endure, especially because I'm cutting the plywood. The pieces are now drying (they were wet to the touch when I got it at Home Depot, and I've read that they do the pressure treatment and then directly palletize those stacks of plywood, so it *should* be soaked unless it got separated and stored dry somewhere along the way.

What do folks here suggest for gluing the three layers together? I think epoxy would be safe, though perhaps a little pricy. Is there anything else preferable?

And what do folks suggest as a preservative treatment? Mostly the things I can find are water based, which doesn't seem to me like it will do much. I did find an oil based waterproofer and used it on another part of the existing ramp already. I was hoping something like creosote or bitumen, hot pitch, I dunno, something penetrating and evil smelling. These are kind of hard to find, and instead I'm finding things with trick names that sound like these but advertise water cleanup. I did find one product that is oil based with some copper compound, which sounds best so far.

This whole thing is less than 3' by 4', so I could probably use something fairly expensive in a small quantity. I'm also wondering if I can come up with a way to soak it, or at least soak the cut edges, for an extended time.

Any suggestions?
Thanks!!
 
   / Treatment for PT plywood for outdoor ramp #2  
I've covered GC plywood with several generous coats of paint, and they have been trouble-free after 10 years. Just be sure to get the ends real good.
 
   / Treatment for PT plywood for outdoor ramp #3  
?? How about connecting a 2X8 to the edge,, so the plywood does not touch directly??
 
   / Treatment for PT plywood for outdoor ramp #4  
Titebond 111 is rated for outdoor use, I've had good luck with it.

Epoxy would be expensive but would probably be the best.

SR
 
   / Treatment for PT plywood for outdoor ramp #5  
Glue isn't going to want to stick to wet wood very well, though a polyurethane might do OK as they use moisture to cure (Gorilla glue). But why glue it at all? Get a small pack of 1.25" SS screws and screw together the layers. Easy peasy. Just make sure the points face down incase any poke through at all. You can buy the pressure treatment chemical in the paint section of most home centers, if you want to hit the cut edges. Just make sure you have goggles and gloves on as it is nasty. Or just a few coats of regular paint as Jay suggested.
 
   / Treatment for PT plywood for outdoor ramp #6  
Glue isn't going to want to stick to wet wood very well, though a polyurethane might do OK as they use moisture to cure (Gorilla glue). But why glue it at all? Get a small pack of 1.25" SS screws and screw together the layers. Easy peasy. Just make sure the points face down incase any poke through at all. You can buy the pressure treatment chemical in the paint section of most home centers, if you want to hit the cut edges. Just make sure you have goggles and gloves on as it is nasty. Or just a few coats of regular paint as Jay suggested.
Glued plywood is stronger than unglued. A polyurethane type glue is what I'd use with some screws as you suggest. If they came up from the bottom and don't perforate the top layer, less water would be ingested.
 
   / Treatment for PT plywood for outdoor ramp
  • Thread Starter
#7  
Glued plywood is stronger than unglued.
Yes, this is a very important point. The stack will try to bend when loaded, stressing the glue in shear, and if the glue can hold the stack can carry way more weight. Just think of leaf springs on a vehicle, and imagining replacing a leaf spring with a solid chunk of steel with the same overall dimensions.

Thanks all for the replies, I'm really appreciating them as they come in!!
 
   / Treatment for PT plywood for outdoor ramp #8  
What will hold this ramp in place so it doesn't slip now that it will rest on asphalt instead of digging into the dirt?
 
   / Treatment for PT plywood for outdoor ramp #9  
I've covered GC plywood with several generous coats of paint, and they have been trouble-free after 10 years. Just be sure to get the ends real good.
We have a Pressure treated ramp over the front steps that is over 10 years old and we coat it with good oil based porch paint every summer and it's holding up just fine. Let it dry out first and then a couple coats of quality porch and deck enamel will do the job.
 
   / Treatment for PT plywood for outdoor ramp #10  
I would form it up & pour concrete. Broom finish.
 
 
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