Best wood & concrete protection for above-pond deck

[dave]

Hi, This past summer I drained my fresh-water pond and built a large deck. It sits on 9 large pillars (5' of water plus 3' into bottom) and the underdeck is made of pressure-treated wood. Its reached by a

18' bridge. After I refill the pond, the pillars and under-deck wood will be pretty much inaccessible. (Pond refilling is easy but draining was a major, major task.) What would be good coatings/paints/sealers/etc to cover the wood and concrete to prevent long-term damage (including water seeping into concrete and cracking it during cold Michigan winters.) The deck beams and joists will sit about 12-18" above the water surface. They won't get soaked but they will be in a semi-permanent damp location. I'm looking for help from anyone who has first-hand experience with docks, decks, etc that sit above water in cold-weather climates. (The pond is a 1/2 acre fish pond/garden with goldfish and koi that can't be harmed by any chemicals in the products.) Right now they are living in a separate area. I need to get this concrete and pt wood taken care of, the pond refilled, and the fish back, before the water temp gets too cold.

Thanks very much for your help.

dave

[tinacci336]

Having worked in a wood treating plant for ten years its my opinion that "Treated Lumber isn't very reliable unless it is cresote or penta treated. The two woods that normally will stand water and not rot are teak and redwood. Teak being the best. In your case I wouud contact a good paint company for advice.

[gfretwell]

The real answer was the level of pressure treating you had in the pilings and deck. All PT is not created equal. When you build a dock in Florida you use 2.5 CCA pilings and 0.8 for above water lumber and it will last 20 years or so in salt water. You might not even be able to get that where you are. The second thing we do is to wrap the pilings with a thick black plastic sold for the purpose to hold down marine organisms. The jury is still out on how long the CCA substitutes are going to last but when you are building a dock they will still sell you CCA lumber here so that tells me something.

[Phisherman]

I like Cabots Decking stain. If applied and allowed penetrate PT wood, it should protect for 3 or more years. Allow the finish to dry for a month before adding fish. A wax-based product is less toxic, but expect the wax to last 6 months.

[dave]

(snip for brevity)

I'd like to thank those who offered suggestions and ideas/help in response to my original post. I appreciate the time you took. Since yesterday I have done a lot of research and investigating. At this point I have decided to use an epoxy paint on the concrete and Olympic 8-year deck stain on the wood. The epoxy paint should last indefinitely, but I may need to add a uv-protection topcoat over it (at least near the top, where sunlight still gets through the water.). As far as the deck stain, even if it only lasts 3-4 years, I should be able to drain the pond down a few feet, and use a rowboat to get under the deck and restain the wood as needed. A tight fit, but do-able. And it could be a good safety check as well.

Thanks again for the suggestions and ideas.

dave