Highly durable waterproofing finish for outdoor wood

Old 06-10-18, 07:14 PM
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Highly durable waterproofing finish for outdoor wood

I have covered an outdoor netted racquetball practice area in the back yard with OSB boards. Unfortunately, even though there are enough 2x4's underneath the floor to keep it from bowing, it does need further protection against the weather. I have covered it pretty well with Thompson's Water Seal but it is not enough. I hear that a poly-urethane that is rated for outdoor use is the way to go. I want to preserve as much of the original color and texture as I can and will probably mop on the finish. The area is about 16 x 32 feet. What sandpaper should I use to sand it and what poly-urethane finish should I buy? Links to the correct finishing product(s) are greatly appreciated.
Old 06-11-18, 02:17 AM
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TWS makes it difficult to apply any other type coating! One of the ingredients of TWS is some type of wax that will repel other coatings. Nothing water based will adhere well to TWS! You pretty much need for the TWS to wear off and then use an oil base coating. Spar poly is the exterior clear you'd want to use but on a flat surface like that it will take a beating from the elements. Since you started with TWS it might be better to continue with it, recoating about twice a year.
Old 06-11-18, 04:38 AM
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OSB is difficult to keep alive out in the elements. It's just not intended to be exposed. You might be fighting a loosing battle trying to preserve the OSB. You can probably prolong it's life but I would start thinking of what you should replace it with in the future.

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