Before applying wood stain, paint, or sealer to your deck, you need to sand it. Sanding removes the top layer, takes away the existing stain, and removes dirt too. But how long does it take?
On average, it will take you around 1 hour to sand a deck that is 10 square meters using a random orbital sander. That’s roughly 6 minutes per square meter. However, that figure may vary as there are several things that impact sanding time such as the type of sander used.
There are a number of factors that can increase or decrease the amount of time it takes to sand your deck. Read on to learn more about what those factors are, and pick up some great tips on how to speed the process along.
What Affects the Time it Takes to Sand a Deck?
Of Course, the Size of Your Deck
Naturally, the size of your deck is the biggest factor to consider and you don’t need me to tell you that a larger deck takes longer to sand. It’s not just about square footage, though, you also have to consider the total surface area and the difficulty of sanding certain features. For example, stairs are quite tricky and increase the time it takes to sand quite a lot.
The Current Condition of Your Deck
If your deck is weathered and damaged, it will take longer to sand than a deck that’s in good condition. When you have stain that is in good condition, it comes away easily and you’re left with nice wood underneath. But if the deck is heavily weathered, you actually have two layers to remove; the upper layer of remaining stain, and the weather damage below. Once the stain is removed, you will notice grey/black patches that need to be sanded off too, and these take longer.
The Current Coating on Your Deck
The type of coating you have makes a difference too. Dark colors or certain brands will take longer to remove than others. Some can be a real pain while some will come off easily without too much elbow grease. Ideally, when choosing products, look for ones that are easy to sand off when you need to reapply in the future.
The Type of Sander You Choose to Use
There are several types of sander you can use on your decking and some will be quicker than others.
Orbital Sander 
An orbital sander moves in a circular motion to gently sand the deck. You can also use random orbital sanders that move forward and backward at the same time, which prevents circular marks on the deck. A good random orbital sander will make short work of your deck.
Belt Sander
A belt sander is another popular choice. It’s a simple sander that moves the sandpaper in the same motion you would with your hand. Again, it is very effective for sanding decks and both a belt sander and orbital sander should easily cover a 25m square deck in 8 hours without too much trouble.
Detail Sander
There are certain areas (around stairs and railings, for example) that are hard to get into with an orbital or belt sander. Detail sanders, with a small triangular head, are perfect for getting these small areas. But they will not strip the wood as quickly, so should only be used for small details.
I would recommend using a random orbital sander to sand the majority of the deck, and then use a detail sander to finish the hard-to-reach areas. When picking a sander, there are a few key features to look for. Firstly, a dust collection bag that fits on the back can be a huge help as it keeps mess to a minimum and makes cleanup easier.
Secondly, look for a sander with adjustable speed settings. At the beginning, when you are removing a buildup of dirt and a thick layer of stain, you want your sander to be fast. But as you get through it, it’s useful if you can cut the speed to avoid sanding too hard and damaging the wood.
What is the Grey or Black Coating on My Deck? Is it Hard too Sand?
The grey or black coating on your deck is caused by weather damage. It is a combination of dirt that has settled into the wood, and mold and mildew. Removing this coating before you stain the deck is crucial if you want the wood to stay in good condition.
The good news is, as long as you’re using a good sander, you will be able to remove it. It takes longer than sanding a deck that is in good condition, but it will come away fairly easily.
How to Speed Up the Process of Sanding Your Deck?
Use High-Quality Sandpaper
You might think that all sandpaper is basically the same but it isn’t. Low-quality paper gums up easily, meaning that it doesn’t sand as effectively and you will have to change the belts or pads more often. Ultimately, you don’t actually save money by getting the cheap stuff because you have to use more of it. But you will waste time, so always buy high-quality sandpaper.
Buying plenty of belts or pads will speed things up because you don’t have to keep sanding with worn out paper. Around 20 is a good number for an average sized deck.
Avoid Sanding in Extreme Heat
Extreme heat can make your sandpaper gum up faster too. So, pick a fairly mild day when it will be dry but not too warm.
Make Sure it is Dry
Sanding your deck when it is wet is a huge waste of your time. The paper will clog up and rip in seconds and you’ll make a big mess. So, if you wash the deck before sanding (which you should), make sure you let it dry fully before you sand it.
Ask for Help!
If in doubt, ask for some help from friends or family. You’d be surprised how far a few cold beers can go when you need a hand with a job. If you get a few sanders and tackle it together, things will move much faster.
Should I Pressure Wash Before Sanding?
Yes, absolutely. Pressure washing your deck removes the surface layer of dirt and starts stripping the stain. When you start sanding, there will be less to take off and the paper won’t gum up as easily because you have cleaned off the dirt. Just make sure that you keep the pressure between 1000 and 1200 psi to avoid damaging the wood.
Can You Sand an Old Looking Composite Deck?
No, if you have composite wood decking, do not sand it because you can do irreversible damage. If you want to protect and revitalize your composite deck, you need to clean it properly instead. Check out our great composite deck cleaning guide for some advice.
Final Thoughts
Sanding a deck can be a time-consuming job, but it often takes longer than it should because people don’t invest in the right equipment. Preparing the deck properly with a pressure washer, and using a decent sander with good quality sandpaper will speed things along. Roping a few friends in to help can’t hurt either!
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.