Because It’s Like A Nice Raincoat… For Your Deck

Deck weatherproofing is one of those nagging home maintance things that isn’t really interesting. I’m probably not going to change that. But it makes a world of a difference. So do it. 

This is the second year I’ve weatherproofed my unstained deck. If you have a stained deck, don’t rely on that fresh coat of stain to serve as waterproofer, go over it with a clear coat to seal the wood and block out, well, the weather. I felt a hell of a lot better with a foot of snow sitting on my deck for 2-months straight last winter knowing that the boards were impervious to the hazardous moisture, freezing, and expansion. More so than if I had done nothing, at least.

My deck remains unstained because I still dig the way lumber wears naturally. If I were to stain it, I’d probably aim for a medium-dark brown, but that’s not in the cards yet. Maybe a few years from now if the boards don’t weather from the sunshine evenly, but in any case, I’m not overly worried about that right now, but I am making a conscious effort to make the strong lumber last.

I looked at the next 7 day forecast yesterday morning and cringed. It’s pure rain. And even if those meteorologists are only 40% right on, news of rain got me moving. It’s been dry for at least the last week, meaning that the board were totally parched and welcoming of a nice coat of weather-protectant. Far be it for me to speak for all deck owners, but natural wood decks in my experience do not require much maintenance, just a regular cleaning and some TLC. You wouldn’t go without sweeping your floors for years on end, would you?

Last year, I splurged on a 2.5 gallon-sized can of Thompson’s WaterSeal Clear Multi-Surface Waterproofer, which I figured was more than I needed for the deck at the time, but didn’t actually believe it would be enough for two years worth of waterproofing. It was a pleasant surprise that I didn’t need to invest in another container this fall. I’m sure there’s some kind of “the oil burned for 8 nights” story in there (except replace the oil with the waterproofer, replace burned with rolled, and swap 8 nights with approximately 350 square feet.)

In any case, both pergolas, railings, steps, the entire 275 sq. ft. deck, and the entire front porch received a fresh coat and are begging for rain and snow. So bring it on, Mother… Nature.

I started my weatherproofing process with the pergolas and second tier areas of the deck for good reason; weatherproofing the pergolas above your head is kind of a pain in the butt. There are inevitable drips, which is why I followed up with a good clean coat on the areas directly beneath the pergola. If left to dry in place, those drips that fell from the pergola may have left obvious spots where the coverage wasn’t even, so immediately smoothing them out helps immensely.

But that right there is the only thing I really think about when I’m in full-on waterproofing mode. There’s not much you can do wrong.

The deck surface itself is pretty easy to do in a quick afternoon with the right weather and the right tools. I’d prefer to have waited until the evening to get my coating on, but the sky was overcast and not blazing sun all day yesterday, which made for nice conditions. I understand that sometimes the sun dries the coating too quickly without giving it an opportunity to absorb fully, so shady days and evenings are typically recommended. A regular paint brush will take a little longer and (duh) feel just like painting a huge surface and, if you’re like most people you’re always going to be wanting to find a faster alternative. Consider reusing a cleaned paint roller, even if in my experience it tends to hold too much waterproofer and ends up going on thiiiick if you’re careless. The Thompson’s clearly says not to go hog wild on the waterproofing application, and I like to adhere to that recommendation by applying a single, thin coat with not too much excess. This might also be why I’ve somehow made a 2.5 gallon container last two summers when it’s only forecasted to cover 500 sq. ft. for the typical consumer coating smooth wood.  

My tool of choice for waterproofing application has been a repurposed paint edger, a 6″ flat paint rag-like tool with a handle that is meant originally for making it easier to cut into trim while painting.

In this case, it’s the perfect width to cover a 5/4″ deck board with a clean application of deck sealer in one fell swoop.

I will credit the paint brush for one second – it is nice to mash an old brush coated in waterproofer into the cracks between boards and into tight spaces; forgetting to coat the narrow gaps between boards is like forgetting to floss all year. The water will get in, and will damage your boards slowly over time (at a faster rate than the protected top surface).

In any case, after you coat the deck it’s going to go from looking like this (on the left) to this (on the right). I like to take this moment to think “Oh, so this is what the deck would look like if I stained it a subtle brown.”:

You’re going to see an instantaneous improvement in it’s ability to repel water. Give it a few hours to cure and the go ahead. Flick some of your Diet Dr. Pepper on there and see how it levitates on the surface before the dog comes to lick it up.

You’re also going to be amazed when it rains for the first time and you see how the water just sits on the deck boards (in a little bit of a teasing fashion, pointing out where certain boards bow and warped to be more like spoons). Yes, it rained just last night, about 8 hours after I finished up the jobber. Talk about satisfying.

And the moral of today’s post is that you should treat your deck as well as your fancy clothes.

Accessorized with a rain jacket.