Decks in Michigan have it rough. They’re beaten to death by the sun for 4 months out of every year, experience freezing rain in the fall and spring, and then have to endure the snow for the remainder of the year. Not only does a good deck stain have to protect your deck from the elements, but it also has to look good after people walk on it, and chair legs and grills are pulled across it. That’s a pretty tall order for a cocktail, in my opinion. One of the best ways you can set your stain up for success is to properly prepare the wood to grab onto the stain. Some of my suggestions you may already know, but read through anyway because they need to be performed a certain way.
I think most of you reading this know that this is the most common practice in preparing the deck. The part that most people (including some contractors) get wrong is that the wood should be heavily washed with a lot of pressure. For those of you with the mini electric-powered washers, that means getting the nozzle very very close to the wood as you go along. You’ll know if you’ve powerwashed heavily enough when the wood dries in a blonde color. Not blonde? No go, try again.
You can keep those ugly marks the powerwasher leaves on the wood by making a sweeping motion with the grain. Never stop the nozzle while it’s over the wood. Make an almost 180 degree sweeping motion as you go along. With this method you should almost never have to let go of the nozzle. This is also better for the pump’s lifespan.
After about 48 hours of powerwashing, you may notice a few places where there is some black mold/mildew. If it’s just in a few spots, a paint scraper can usually pull it off. If it’s in more places, get out the belt sander or mouse sander to get the black stuff off. Be sure to wear a face mask rated to stop mold and mildew from entering your body. After you’ve finished you can either spray off the the places you’ve sanded with a garden hose or with something like a leaf-blower to get the dust off.
Do not bleach unless all other methods fail, which is almost never. It’s terrible for the environment, bad for your health, and if it is not completely washed out of the wood, it will ruin your stain.
Just because the deck looks dry on the outside, it does not that it is dry on the inside. If your deck is in the sun for most of the day, you need to let it dry for at least 5-6 days (4 if it doesn’t rain and it’s particularly hot outside). If your deck is in the shade most of the day, wait at least 7 days to let it dry. Be sure to turn off your automatic sprinkler system while the deck is drying. Any rain or otherwise getting on the deck while drying will set you back at least a day. Stain on wood while the core of the wood is wet will wreck your stain, believe me.
Try To Stay Off
Decks get used so often that you may actually find it hard to stay off of the deck while it’s drying. Choose a time when you’re not going to be having any BBQs, tell the kids (if any) to stay off of it, and no pets.
To Sum It Up
Powerwashing should always be your first action in preparing your deck for staining. If there are still some black or green patches, pull out the belt sander or mouse sander to get it off. If your deck is absolutely covered in black mold/mildew, then consider bleach. But be sure to wash every bit of it out later! Lastly, wait at about a week to let it dry in the sun. If your deck is under shade most of the day, wait 2 weeks.
Extra Note: Those of you with brand new decks
Can I stain a new deck with pressure treated wood? I get asked this question a lot. The answer is yes, but not immediately. Many people will tell you that you have to wait an entire year to stain a new deck, but this is not true. If your deck is in the sun for most of the day, you’ll only need to wait about 2 months before staining it. And the best part is, most of you won’t have to powerwash it unless you’re tracking a lot of dirt onto it. Even then you should only have to give it a light touch.