In June 2014 I made this patio table and finished it with Spar Urethane.
Two years later, it looked like this:
The finish failed within a year and mold grew all over the table!
I can only attribute this mess to the finish because I made this planter box two years before the table and, as an experiment, applied absolutely no finish to it. It has been exposed to the exact same weather conditions as the table since it is just a few feet from it.
The planter box still looks great. It makes me question the value of most outdoor wood finishes and whether their benefits are minimal and mostly marketing hype! Realistically, the best protection you can apply to an outdoor project is a coat of house paint, which will last for years without any fuss.
But if you want to retain the look of the wood, I recommend a transparent deck stain and sealer. I’ve used it on many outdoor projects and should have used it on this table to begin with.
To restore my table, I wanted to first remove the mold. I sprayed on some X-14 mold and mildew killer, let it sit for a while, then sprayed it off with my garden hose.
Unexpectedly, I began to notice the urethane finish was actually peeling away from the tabletop.
Here’s I decided to change my strategy and see how much of the finish I could remove with the water, in hopes of reducing the amount of sanding I would need to do. However, it was taking a lot of time and I needed a stronger stream of water, so I went to the home center and bought a new pressure washer, something I’ve been wanting for a long time anyway. (Yay, new toy!)
This worked out much better!
I let the whole table try overnight and began sanding the next morning. There was still a lot of stubborn finish that needed to come off. I used 80 grit sandpaper in my sander. It’s important to remove all the old urethane finish or the stain will not soak into the wood and work.
This was a LOT of sanding. Took about three hours.
I blew off all the dust with my air compressor and began staining. Applying deck stain is super easy: just brush or roll it on. You don’t even need to wipe off any excess as you would with a interior furniture stain.
This dried completely overnight and looks fantastic. If it needs sprucing up in a couple years, I will just need to wash the table and splash on a new coat. No sanding necessary.