Giant Guide to deck cleaning

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What’s the one thing that everyone absolutely loves doing with their spare time? That’s right, eating ice-cream, and watching Netflix. But what do you do once the brain freeze hits, or you’ve finally finished binging all three seasons of that new show you found on Netflix?

Clearly, there’s only one option. You decide to take on the challenging, and satisfying endeavor of cleaning your deck.

Now, you may think to yourself “easy, I’ll sweep it and I’m done”, or “sweet, the hose is already hooked up, all I’m going to have to do is give it a quick spray down”.

If only it were that easy.

Deep cleaning a deck involves 3 steps:

  1. Sweeping and clearing dirt and dust
  2. Stripping and sanding using a pressure washer and power sander
  3. Sealing/painting with your choice of stain or paint

Let’s jump into exactly what these entail.

Why Deep Clean My Deck?

Many large, open structures and the vast majority of McDonald’s ice cream machines will begin to break down if they aren’t properly cleaned and well maintained. Your deck is no different.

Giving your deck a proper cleaning and aesthetic tuneup will not only help extend its useable “shelf life”, but it will make it more appealing to use. Have you ever been on a deck with peeling paint, covered in bugs and cobwebs, with splinters that have a higher chance of doing you harm than the sensei of the Teenage Mutant Ninja Turtles?

Decks like that make you question your will to live. They also make you question your decision to own a deck. So let’s not let it get to that point!

Your deck, since it’s probably made of wood, will swell and contract with the cold, the heat, and moisture. When you go too long without properly cleaning and treating your deck, the small bits of grime and debris that get blown onto your deck will become stuck in the wood, where several things have the possibility of happening.

  1. Your deck will start to grow things. From weeds to mold, since your deck is made of mostly organic material, there is a high chance that things will germinate in the crevices of a dirty deck. And where life finds a way, there are usually spiders. Need I say more.
  2. If the wood in your deck swells and gets any kind of material in it, it’s not going to be able to contract back into the shape it was originally if it was ever going to in the first place. This will increase the level of warping that takes place, not only raising the chances that someone will get slivers from the wood, but that permanent damage could occur to the deck itself.
  3. Last, but definitely not least important, the dirt and debris will begin to stain your deck, and not in a good way. It will begin to get blotchy and very unattractive, which has a good chance of making you less likely to use it.

We’re going to go over how to properly clean and maintain your deck, and we’re going to do in a very in-depth way, so as to hopefully answer all your questions.

Equipment Needed

  • Broom
  • Hose
  • Stiff Bristled Brush
  • Oxygen Bleach
  • Pressure Washer
  • Sander
  • Stain (optional)
  • Paint (optional)
  • Sealant

Initial Cleaning

Let’s jump right into one of the first steps! The initial clean.

You’re not really going to need anything more specific than your own hands and a broom for this. Gather everything that you have on the deck and move it onto the lawn, if you haven’t already. If you don’t have somewhere else to put your things, you’re going to have to do half of your deck at a time, moving things back and forth as you go.

Once you’ve done that, take your broom and sweep up all the debris and dirt up. You’re going to want to get as much of that up as you’re able. If the deck is raised, and you store things underneath it, those things will need to be covered with tarps so they don’t get covered in various cleaners.

If you have gaps in your deck between the boards that are big enough to catch debris, but not big enough for that debris to fall through, you’re going to need to clean that out too. Pens, pencils, an old radio antenna, or a thin branch from something growing in your yard should all be the perfect size to clean out any garbage or junk that your deck is having a difficult time relinquishing.


An important step that often goes ignored is the repair process. Once you’ve gotten your initial surface clean completed, it’s time to complete any fixing you’ve been procrastinating, and look around for any damage you might have missed. Deep cleaning a deck generally involves going over it with a pressure washer, and can include treatments with a number of chemicals. This vigorous and in-depth process has the potential to further damage that has already started taking place, specifically if the damage has needed attention for a significant period of time.

When you consider the fact that you’re going to be moving everything off the deck, and then back on, possibly redistributing weight in a way that a damaged deck may not be able to hold, you’re going to want to take this opportunity to carry out any repairs you’ve been procrastinating.

In addition to repairs you know you need to do, make sure to take this time to examine your deck for things that could cause problems in the future.

Loose nails, screws, or bolts will need to be tightened or replaced. You’ll need to take note of things like dry rot, termites, and mildew, as they can be signs of structural weakness that needs to be addressed, preferably before someone gets hurt.

Not only will repairing your deck before you clean it help you maintain the structural integrity of your deck, but it will also help keep it looking uniform. Repairing the deck after cleaning may leave you with an odd-looking board, or an area that needs to be resanded and refinished, right after you just finished that same process on a larger scale.

Scrub Clean

Once you’ve completed your deck repairs and double-checked for any damage you might not have known about, it’s time to buckle down and start the serious cleaning.

Like we mentioned before, over time, mildew, moss, mold, and other things probably will have started to grow on or in your deck. Short term, this can cause discoloration. Long term, it can cause damage to your deck. This is the step where we deep clean, and take care of that.

There are a number of deck cleaners you can buy from the store that were made specifically for this step that we’ll go over later, but there are also several common household products you may already have that you can use as well.

Oxygen Bleach

Oxygen bleach, when mixed with water, can be used as an effective cleaning agent for your deck. Oxygen bleach, unlike regular bleach, will not change the color of your deck. Regular bleach is almost guaranteed to lighten your deck, and it may not do it evenly. So if you use this method, make SURE you use oxygen bleach.

Oxygen bleach will not only kill bacteria and other things growing in your deck, but the oxygen release process will also help work dirt and grime out of the deck itself.

The ratio of oxygen bleach and water you will need to use will vary based on the specific product and brand you purchase, so check the container it comes in for the measurements you’ll need.

Work the mixture into your deck with a brush, scrubbing it well enough to work out dirt and debris, but not hard enough that you start to splinter the wood. Once you’ve scrubbed it in, let it sit for several minutes before rinsing it off with your hose.

White Vinegar

White vinegar mixed with warm water is another effective household mixture that can be used to kill anything growing in or on your deck. It’s won’t assist you in your cleaning quite like oxygen bleach will, so you’ll have to make sure you scrub well to get all the dirt out.

“I’ll just add baking soda”, you say. The bubbling reaction is sure to help with my cleaning, right? That’s actually a pretty common misconception! Mixing baking soda with vinegar does give you quite a visible reaction that has been used in many science projects, but the chemical reaction it goes through doesn’t give you a cleaner. It actually just ends up being mildly salty water.

Just stick with using the vinegar, water, and a good brush. Mixing about a cup of white vinegar with a gallon of warm water is a good ratio. Once you’ve worked the mixture into your deck, let it sit for several minutes, then rinse it off with your hose.

If you want to go the extra mile, once you’ve scrubbed your deck with the white vinegar, you can spray it with some hydrogen peroxide, and scrub that in too, and let it sit before you rinse your deck off. Don’t mix them together in the same solution though, as you will end up with a bottle of peracetic acid, which can be pretty corrosive.

That being said, peracetic acid in low percentages is actually a great disinfectant, so applying them separately, with the white vinegar mixed into water, is safe to do if you want to add in that extra step.

Important Note!

If you have grease on your deck for any reason, more than likely from outdoor cooking, you’re going to need a de-greaser to get that out. Do not skip over it and just tell yourself that you can use a pressure washer to get it out.

You’ll more than likely just end up pushing the grease deep into your wood, along with the grit stuck in it, leaving you with a nice stain in your deck. make sure you clean the grease off your deck!

Power Wash

If you have the option, now is the time to use a power washer. If you’re going to power wash your deck, you can skip the part earlier where it was mentioned to rinse off your deck after you use cleaners on it, as the power washer will obviously do that for you.

Depending on whether or not your deck is made of a composite, or actual wood, you’re going to need to be careful once you get to this step. If your deck is made of real wood, a pressure washer can easily gouge marks into it, or simply rough up the wood.

So is it really worth the risk? Absolutely. A pressure washer will work out the dirt and grime that has been worn into the wood by months of rain, wind, and snow, which in the long run, will extend the life of your deck.

A pressure washer can also be combined with a cleaner if you so desire. If you decide to go this route, however, it’s suggested that you go with a storebought cleaner that’s meant to be used in conjunction with a pressure washer. You don’t want to mix machinery (especially if it’s rented) with chemical mixtures you combined yourself, and risk damaging the washer.

When pressure washing a deck, with or without additional cleaners, you’re always going to want to start with less pressure. Using too much will not only damage your deck, but will leave visible streaks called “lap marks” across the surface. They look similar to the lines left on a freshly mowed lawn, and newly vacuumed carpet, except in this case, they’re permanent.

The higher the number of PSI (pounds per square inch) and GPM (gallons per minute) you use, the more powerful the spray will be. In addition to spray, you’re going to need to make sure that the tip you select doesn’t concentrate the water too much, which could damage your deck as well.

Use a tip that sprays between forty and sixty degrees, and make sure that the tip you selected doesn’t rotate, as this could cause deck damage as well. Start between five hundred and six hundred PSI. This is generally enough for softwoods, but if your deck is built of harder wood, you may be able to go higher.

Start by cleaning your stairs. If something goes wrong before you’ve fine-tuned the pressure or your technique and you end up needing to replace something, it’s much easier to replace a stair than it is to replace one of the larger pieces of wood from the main part of your deck (and cheaper too).

Start spraying several feet away, and move the wand back and forth in a fan motion until you’re about a foot away. If you’re able, clean each segment of wood individually, as opposed to several segments at once. Doing this may help avoid discoloration from going over each piece unevenly. Don’t go too quickly, as that will defeat the purpose, but don’t go too slowly, as that is what may damage the deck.

This isn’t something you should decide to do if you’re looking for quick and easy. Pressure washing is extremely effective, but if you’re doing it right, it’s going to take some time. Don’t forget to include handrails and other deck railings! Start closest to your house, and work your way out, so you don’t end up just spraying the dirt and grime into the side of your home.

Once you’re done, leave it alone for at least three days. By pressure washing your deck, you’ve pushed water deep into the wood, and you need to make sure it’s completely dry before you sand it, and especially before you seal it. The last thing you want to do after killing the mildew in your deck is seal water inside the wood!


Why save sanding for now? Doesn’t doing it earlier when you were finishing up repairs make more sense? Yes, that does make sense, if you weren’t going to be doing anything that might rough up the wood on your deck after you were done repairing it.

Whether it was going over the deck with the brush, or spraying it down with a pressure washer, there’s a good chance that some surface damage may have been done. The wood may have been scored, or there may have just been some light damage done that made the wood look “fuzzy”.

Well, that “fuzzy” wood is going to dry, and it’s going to be prime real estate for splinters, especially when it comes to handrails, which is why we’ve saved sanding for later.

Not only does sanding help reduce the likelihood of splinters and make the deck more aesthetically appealing, but it also opens the deck up enough so that any stain, paint, or finish you put on it will actually take better.

You’ll want to be careful not to sand it too fine, as the resulting wood dust may engrain itself into the wood and making staining it hard, but sanding it with a grain too large will just make the wood rougher.

A sixty to eighty grit sandpaper will generally be perfect for sanding your deck. Could you do it by hand? Yes. Should you? Absolutely not. Now would be a great time to purchase a rotary sander, if you don’t already have one. You’ll be able to do the job so much faster, more efficiently, and with an even finish.

Before you start, make sure that your deck is dry. Wait three days after pressure washing, and wait at least two days after rain before you sand. If your deck isn’t completely dry, you’re not going to smooth it out, sanding it will just going to tear it up.

Start in one corner and work your way out, like you’re mopping. Sand in the direction of the grain to ensure the smoothest finish, and make sure you’re wearing a safety mask and goggles to protect your eyes and face.

Don’t worry about the wood dust everywhere for now, you’ll take care of that later. Just work back and forth smoothly and evenly, paying close attention to any areas that may have been damaged by the pressure washer, and other areas that already needed some extra love.

Once you’re done, don’t use a hose to clean all the wood dust off, and don’t use something like a leaf blower to blow it off, as this will just push some of the dust into the cracks of the deck that you just cleaned.

Instead, use a vacuum. There are a number of different outdoors vacuums that are perfect for this kind of job. Sucking up the dust will give you a much higher chance of removing the most dust, so when you’re ready to re-seal, stain, or paint your deck, it will go much more smoothly.


We’ve done it! We’ve reached the final step, and now you have a choice to make. Are you going to seal your deck, stain your deck, or paint it? You’re going to want to choose one.

Each one of these products will provide your deck with certain benefits, like water resistance, UV protection from the sun, and a few other things that will help expand the lifespan of the deck.

Taking the time to apply one of these to your deck will help it last longer, which, for you, means less money spent on repairs.
Let’s go over the different products and talk about the benefits of each one.


A sealant is probably the simplest option. They’re pretty basic, generally, just a clear coat that goes over your deck, providing protection from moisture, which will help prevent warping, and will stave off mildew stains.

They do not, however, generally offer UV protection.
If you’ve taken time to observe an older deck, you may have noticed that it has acquired a greyish tinge. That grey color is the result of UV damage, and while you might be able to hide it, there’s nothing you can really do to fix it.


Staining is a great choice if you’re looking to enhance the natural look of the wood. With a variety of great shades to choose from, you’re going to be able to find something that perfectly suits the image you have in mind for your deck.

Staining your deck has all the same benefits as a sealant. It will give your deck protection from water, warping, and mildew. However, unlike sealant, it does give your deck UV protection.

If you decide to use a stain on your deck, test a small amount of it in an inconspicuous spot first, before you apply it to your entire deck. Let it dry, and make sure you like the look of it. If you do, then go ahead and begin staining!

Important Note

If you decide to seal or stain your deck, make sure that it isn’t too hot outside when you do it. Yes, that means it will take longer to dry, but in this case, that’s what you want.

You need the sealant or the stain to really seep into the wood in order for your deck to really benefit from it, and that won’t happen if it dries up too quickly. Shoot for somewhere between sixty degrees at the coldest and ninety degrees at the hottest.


Painting, out final option, will give your deck protection from water, mildew, and warping. It also has the strongest UV protection, since it generally gives an impenetrable coat between the sun and your deck.

That being said, it’s important to remember that paint peels. Once the paint on your deck starts peeling, it all goes downhill from there. Everything starts looking tacky, and you’re generally going to have to strip all the paint off your deck before you can change your mind about the color of the paint, or apply a stain instead.

All Done!

Once you’ve applied a sealant, stain, and paint, you’re done! Give the deck a couple of days to dry, and once that’s done, feel free to move everything back onto the deck, being careful not to scrape up your hard work!

Products To Use


Unger Professional HydroPower Bi-Level Scrub Brush, 10"

This brush is perfect for scrubbing a deck! It’s curved, which will allow you to easily scrub from various angles, and the synthetic bristles mean you won’t have to worry about reactions between the brush and any chemicals you use.
Click here to buy one from Amazon.

Deck Cleaner

Star brite Mold Stain & Mildew Stain Remover + Cleaner - Lifts Dirt & Removes Stains on Contact - Gallon Size
This deck cleaner was made specifically for cleaning up things that have gotten dirty, or begun to grow mildew from spending too much time outdoors.
Be careful though, as it does contain bleach, so you’ll need to provide protection for your grass and surrounding plants if you plan on spraying it off.
Buy it here from Amazon.

Oxygen Bleach

OxiClean White Revive Laundry Whitener + Stain Remover, 5 Pound

When it comes to cleaners, you can feel safe about using oxygen bleach. Unlike regular bleach, oxygen bleach is safe for the environment, which means you don’t have to worry about spraying the excess on your lawn when you’re cleaning it off your deck.
Buy it from Amazon by clicking here.

White Vinegar

30% White Vinegar - 300 Grain Vinegar Concentrate - 1 Gallon of Natural Concentrated Industrial Vinegar

White vinegar has commonly been used to replace toxic cleaners and chemicals for a variety of jobs, and you can feel safe using it to clean your deck.
Check it out on Amazon by clicking here.

60 Degree Pressure Washer Tip

Pressure Washer Sprayer Low Pressure Nozzle Tip Soap Nozzle, Color Black 60 Degree Spraying Angle Brass Quick Couple for Pressure Washer

While you may already have a pressure washer, or can rent one from a nearby store, you may have to provide your own tips, especially since you want a wider angle for cleaning off your deck.
You can buy this 60-degree angle tip from Amazon by clicking here.

Orbital Sander With Sandpaper

BLACK+DECKER BDERO100 Random Orbit Sander, 5-Inch with PORTER-CABLE 735800825 5-Inch 8-Hole Hook and Loop 80 Grit Sanding Discs (25-Pack)

This sander is exactly what you need to tackle a project like sanding a deck, and it will come in handy for a lot of other things later on. Even better, it comes with the 80 grit sandpaper you need!
Buy it from Amazon by clicking here.

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