Waterproofing plywood??

550Doug · Nov 6, 2010

What is a good covering to use to waterproof a piece of plywood that will be exposed to the outdoors? Maybe the paint-on pickup bed paints? Old motor oil( sure!!!!)? Any other ideas?
Thanks

old · Nov 6, 2010

Any good oil based paint will do that as would something like Tompkins weather seal

VaTom · Nov 6, 2010

I've done very well with used motor oil on my plywood concrete forms, boat hull paint on exterior planters with marine plywood, and epdm on plywood roofs.

Much depends on what you want it to look like.

JDemaris · Nov 6, 2010

That's what marine-varnish is made for. It's ozone resistant and won't break down from sunlight, unlike many paints and polyurethanes. Or . . . just get some pressure-treated plywood and don't worry about protecting it.

rustred · Nov 6, 2010

"good oil based paint" , now thats something thats going out the door.even the bodyshops are using water based paint now.i do believe in the oil based paint for preservation though as it soaks right in compared to the water base that sits on top and then peels off in a couple years.

Anonymous-0 · Nov 6, 2010

Plywood is used in marine construction a lot. The best way is to soak it well on all sides and edges with epoxy resin. I have used WEST. Then sand and prime then paint with marine polyurethane. This all adds up to an expensive piece of plywood though so you have to decide how good is good enough.

showcrop · Nov 6, 2010

Consider Advantec OSB instead of the plywood.it carries a VERY impressive warranty.

BCnT · Nov 6, 2010

just get marine grade plywood to start with...its the toughest of all the plywood and needs minimal upkeep.

big fred · Nov 6, 2010

I used MDO plywood to make some signs, painted with plain old Krylon rattle can. Lasted 12 years, at which time we took them down. The plywood was still in good shape. The trick was to start with MDO board, which is intended for outdoor use.

MarkB_MI · Nov 6, 2010

If you want it to be truly waterproof and last forever, the only solution is to saturate it with epoxy resin. If you just need it to last a few years, then any exterior paint will be sufficient. The important thing with plywood is to saturate the end grain, as that's where the moisture comes in and rot starts.

550Doug · Nov 6, 2010

Thanks for the ideas, some very high-end solutions that may be more than I need but I will try some of the ideas (especially since you jogged my memory that I do have an old can of Thompsons somewhere).
Thanks

Ky Hauler · Nov 6, 2010

I used liquid silicone on an emergency dog ramp several years ago. Coated both sides twice. Has held up longer than I expected. I also use it on new brick window sills to shed water. Why did they get away from solid limestone sills anyway?
You may have to buy a five gallon can though. A good concrete company should have it. Can't remember the price.

Waterproofing plywood??

550Doug

Member

old

Well-known Member

VaTom

Well-known Member

JDemaris

Well-known Member

rustred

Well-known Member

Anonymous-0

Well-known Member

showcrop

Well-known Member

BCnT

Well-known Member

big fred

Well-known Member

MarkB_MI

Well-known Member

550Doug

Member

Ky Hauler

Member

Similar threads