Thread: best deck finish ?

The best clear finish is several coats of two part polyurethane over at least three coats of epoxy.

The next best is single part polyurethane over the same.

Next is high quality marine varnish (oil based) over the same.

Further down the list is any of these coatings over raw wood. This would additional include shellac, and traditional oil finishes.

Water base variants of the above aren't as good as their solvent based brothers.


Shellac over epoxy doesn't work very well as it doesn't have much UV protection and the epoxy will "bake". Oil finishes can't go over epoxy. These also don't offer much UV or water ingress protection.

The two part polyurethane is the most costly, followed by real marine varnish, followed by single part polyurethane, with shellac and oils way down the list in cost.

thanks par ,by epoxy you mean the 2 part wood hardener ?

Originally Posted by mongrell

thanks par ,by epoxy you mean the 2 part wood hardener ?

He means the the 2 part marine epoxy glue such as produced by West Systems or Bote Cote. You'll be using it unthickened (ie, just the resin, not adding powders).

Richard

You'll be using it unthickened (ie, just the resin, not adding powders).

Just to be clear, unthickened epoxy, is epoxy neat, straight up, nothing else, no fillers, but it does mean both resin and hardener are added, mixed well and in the correct ratio.

I mention this because of a fellow who read "nothing added to the resin" (on a different forum) and then promptly applied just the resin and was back asking how to get it to cure faster . . .

Originally Posted by PAR

I mention this because of a fellow who read "nothing added to the resin" (on a different forum) and then promptly applied just the resin and was back asking how to get it to cure faster . . .

wow

I'm thinking a case of what was greener the builder or the epoxy.

Hmmm........what am I laughing about

Mongrel,

celery is a really nice deck in the raw, uncoated state and it silvers off nicely.

I'd get rid of the everdure and go natural.

just my thoughts

AD

par what would the maintenance regime be with the epoxy and two pack and how long roughly would i get out of it ? blogs the raw state is definately the easiet and cheapest but its got a lovely deck and nothing looks better than a good deck , boats the ronnell it was in hobart for a couple years and before that was in king island for 25 , maybe youve seen it

The durability of any coating is dependant on several factors. The usually suspects are; UV exposure, climate, dirt moisture and the amount of traffic it's expected to endure.

UV damage is the big one after abrasion (traffic). No coating can tolerate being walked on for very long, it literally wears off the surface. Clear coatings are physically disadvantaged compared to other coatings. This is because the things that can make the coating tough and durable also contribute to opaqueness. This is why paints lasts longer then varnishes.

Where you live and how much exposure to the sun your deck gets, has a good bit to do with it too. I'm at 28 degrees north, so clear coatings don't last long here, which is typical of tropical environments. I have friends that live 1,000 miles north of here, who get two or three times the life from the same clear coatings I use. This sucks, but is the price I pay for BBQ's in the dead of winter, while they have several feet of snow on their grills.

Dirt and moisture also affect durability. One drop of water on a finish in the sunshine, acts like a miniature magnifying glass, cooking the surface below. Dirt is ground into the surface as you walk on it.

To answer you questions, keep it's deck clean and out of direct sunlight when not in use. Provide good ventilation so moisture can evaporate quickly and discourage mold and mildew forming. The amount of durability is quite variable. I can get two full seasons from a two part poly over epoxy finish in my climate, if it sees lots of use. If it's a trailer queen and lives in a car port except for the 6 times a year you actually roil it to the local puddle, you could get several years before needing to recoat.

A note about two part polyurethanes. These are especially hard coatings and not suitable for all surfaces. Sealed and stabilized wooden surfaces work well with these coatings, but unsealed wood that has a fair bit of moisture gain, will probably "move" too much for the coating to stay stuck. It will not comes off in big sheets, will likely crack at seams and joints. In these cases you're much better off using a single part urethane or traditional oil based varnish. These two part polyurethanes can be top coated and refreshed, but are extremely difficult to spot repair. Varnish and single part polyurethanes are much easier to repair. In other words, don't let the poly coatings "get away from you" or you'll have to strip the whole thing down and start over.

How long will it last, who knows, I sure don't have an answer. Raw wood dies fairly quickly on the deck of a boat (this assumes the boat is used regularly). Since your deck has been coated already, you're pretty much married to some sort of clear coating. Raw isn't possible for you and it's a very lubberly way to have a deck. Some think the nicly silvered decks look fine, but to a sailor, it's just a sign of lack of maintenance or an uncaring owner.

Keep it clean, dry, out of the sun and it can last a long time, much longer then traditional varnishes. Neglect it and it's harder to get it right again, which seems reasonable justice.