The arrival of hot, dry weather reminds me that, though it may be tedious to work in, it’s perfect for the annual drudgery of the deck. Dry heat is aces both at quickly evaporating water used to clean and prepare the deck, and at curing the finish.
In my case, annual is an exaggeration because I don’t get to the deck every year. In fact, I’ve let it go so long that the finish has now given way to a piebald mess of dirt, mildew and bleached gray planks. No matter; it’s easy enough to rejuvenate.
After sweeping off the detritus, I hose down the deck to see just how bad things are. This year, I’ll need bleach to kill the mildew, TSP (trisodium phosphate) soap for the dirt, and then oxalic acid to restore the wood’s natural color. Luckily, I can combine the first two steps.
Scrubbing with a synthetic bristle brush (bleach eats natural fibers) dipped in a mixture of laundry bleach watered down with a TSP solution kills the mildew and dislodges the dirt in one step. Bleach and TSP can be mixed, and some ready-to-use deck cleaners are just that. However, you can’t combine chlorine bleach and ammonia-based cleaners; that creates a poisonous gas.
Moderate scrubbing followed by hosing off gives me a clean surface, but to restore the wood’s natural color I’ll need oxalic acid, often sold as deck brightener. This time I don’t need to scrub, and any applicator will work. The quickest is a swab mop to liberally apply a 10 percent solution of oxalic acid. Once it dries, out comes the hose again to wash off the white residue. Of course, I could probably do at least two of these operations at once with the superior firepower of a pressure washer, but I don’t own one, and these inexpensive chemicals do just fine, thank you very much.
With luck and a dry night, the deck will be ready to coat in the morning with one of dozens of oil-based and water-based choices lining the home store shelves. With deck stains, which is what most deck sealers are called even if they contain only a soupcon of color, the cost and quality go up hand in hand. I’ll bite the bullet and get an oil-based, semitransparent deck sealer with mildew control and UV resistance. Olympic, Cabot and several other companies offer quality choices. However, both F&P (from Wolman) and CWF (from Flood) win my affections by offering high quality paired with comparatively low prices, though even these will set me back $25 per gallon.