How to Sand a Deck – In-Depth Guide for Best Sanding Results

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Maintaining the decking outside your home might be a tiresome task, but it sure is a rewarding one when the wood lasts a lot longer than if you left it to the weather. Something that is essential for maintaining your outside deck is to sand it down when it starts looking a bit worse for wear and apply a new coat of varnish. For this you will need a deck sander. You can use a belt sander for a deck, or an orbital deck sander, both of which we will discuss today within this tutorial.

How to Sand a Deck

Now that you are fully aware of all the little things that could make or break your deck sanding mission. There are a lot of advantages and disadvantages to expect with any form of sander, but at least they all work in pretty much the same way. Here are some guidelines to follow that will make the process so much more effective. Make sure you have adorned yourself in the finest protection gear because your safety and comfort are very important.

Clean the Surface of the Deck

Any task that involves a bit of construction work will need to start with some cleaning, and inevitably end up with more cleaning. If you avoid the initial cleaning process you could ruin the sanding process and thus, waste some precious time and resources. Your sanding machine will work more effectively if you clean the surface of the deck first because the grime that will be scraped off with the wood, will end up ruining the sanding disk that is the key ingredient to the orbital or belt sander for a deck.

The best way to clean your deck, and the fastest for that matter, is to use a pressure washer. Make sure that the wood is strong enough to withstand the high pressure before you switch it to its highest setting. Sometimes a low setting is good enough for the softer woods. Make sure that you wait for the wood to be dried fully before you move on to the sanding.

Preparing Your Surface

There will inevitably be a lot of foot traffic on the surface of your deck because they are meant to be used. They are perfect when you have friends over for a barbeque and you have some tables and chairs facilitating the comfiness, and a great view to accompany you. This does mean that there will be a lot of wear and tear, and most likely in a short period than you might care to admit. This just means you get to bust your sander out and have some fun using your power tools.

Before you sand it down, make sure your wood has dried properly after you cleaned it. Once you are certain it is dry, remove any nails, screws, or any other foreign items that might get in the way of your sander, and prevent it from sanding properly, or worse, damage the sanding disk.

Next, we would highly recommend getting some wood filler and filling in the gaps that were left when you removed the screws. Sometimes there is a gap regardless of any screws having been there – fill those holes too! You will then sand them down later and you will not even notice that there was a hole there in the first place. Make sure you wait for the filler to dry before you start sanding.

Sanding Your Deck

Now for the part that you have been waiting for! You have prepared everything you could think of preparing, and now the deck is waiting to be sanded down. Make sure that you have your battery charged if the sander you are using requires one or make sure you have an extension cord long enough to reach the end of your deck. The sandpaper you should be using with your orbital sander should have a grit of about 60-80, which is quite rough. You can use a finer grit when you get the final sand over to smooth out the surface.

Sand down each board’s length starting at one point on the board, starting at the top, and working your way down. To ensure that you achieve a consistent finish over the entire surface of the paper, it is imperative to take your time and minimize the pressure you apply. Using a belt sander for a deck with minimal pressure is the simplest way to do this, especially with a hardwood deck. Although an orbital sander with sufficient power can accomplish the same thing, it all depends on how you approach and the technique you use.

The goal is that once you have sanded about a quarter of the deck’s surface, you will be able to see whether or not you have that perfectly smooth and even finish over the whole deck. If you feel you need to go over a few spaces, feel free to do so. The next thing you need to do is to work on the railings once you have finished the deck’s surface. Remember you should be using finer grit sandpaper depending on the type of wood used.

When you are sanding down the railings of the deck we recommend doing so manually. There are too many different angles for the railings and you might struggle to move the sander around easily. This might cause some damage to the surface of the railing.

Sanders Suitable for Maintenance

To maintain your deck, you will need to use one of two types of electric sanders that are designed for this purpose and style of sanding. They are not the most affordable of all sanders, so you must make sure you get the right one. The one type of sander you could use is called the pneumatic sander, and the other is your standard orbital sander. In order to understand which is the better option for the job you have on hand, then you must understand the differences between all the machines.

Pneumatic Orbital Sanders

Compressed air is the staple ingredient to success in any auto body workshop. They use it to inflate the tires of the cars, give them spray paint jobs, and clean the car of all dirt and grime. Funnily enough, some electric sanders, known as pneumatic orbital sanders are amazingly powerful because they also make use of the power of compressed air. They might be a little too powerful for sanding down your deck, and they can be hard to move around or control, so if you are not skilled yet, we recommend gaining some experience with these guys before you attempt anything that might ruin the deck forever.

This type of sander will need a compressor bought separately because they do not come included. This might be what causes the tool to be expensive for you, and it can end up taking a lot of space so they are hard to store when not in use. 

Electric Orbital Sanders

An orbital deck sander is the best way to sand a deck. This machine is much easier to control than its pneumatic counterpart, and it makes it the preferred tool to be used by most DIY experts, and even professionals prefer to use it for the ease it offers. It is less intense with the sanding as the pneumatic sander, and this means there is less risk of damaging the surface of the wood.

Many orbital sanders will have attachments included, like a brush attached to the sander so that it sweeps up the dust as it stands, a vacuum to suck it up, and possibly even a container that catches all the dust so there will be less mess to clean up when you are done. Orbital deck sanders are not limited to sanding down decks. They are quite versatile and they can be used for many different types of jobs. This makes it a great investment for your workshop.

That being said, if you are skilled enough with a pneumatic sander, then we suggest you stick to the big guns because those machines are phenomenal sanders if you have the right know-how and practice.

Electric Belt Sander

If you thought that pneumatic sanders were too strong, wait till you try out a belt sander for a deck. This is a bit too much strength for simply sanding down your deck. However, with the right amount of skill, you could use it for just about any large sanding job. They are suited for sanding and trimming down the edges, so if you need to smooth down the railings you will find this tool helpful.

The motorized sanding mechanism of these machines packs a big punch. Therefore, you must practice a bit before sanding down the deck at home or work so that you do not damage the smooth and flush surface. To find out a bit more from craftsmen who have tried these tools out and posted their reviews online. There are a few sites where you can find some epic comparisons of the different sanders, but ultimately, the belt sander is the more intense sanding machine.

If you are looking for the best sander for deck refinishing, do not be scared away from using a belt sander if that is the type of sander you have at home or in your workshop already. They can be used perfectly and can produce some outstanding results with the right amount of skill, and if you work with patience.

Features to Consider When Buying a Deck Sander

As you can see from the various sanders that we have listed above, there are a few features and characteristics that have made them more popular. Human beings are prone to leaning towards the more convenient side of life, and we can all see the designs have considered this. What are the additional features that are good to look out for when purchasing your electric sander? Let us take a look at a few examples.

Which Sander Type Is Best?

There is no saying which is the better designed electric sander. This will depend entirely on you, your skills with the power sander, what you need it for, the size of the surface you are sanding, and a bunch more factors. If you use the wrong end, and you do not have the right skill to master the intensity of the sanding mechanism, the deck’s surface has a high chance of dents being made from the sander being too strong for it.

There might still be some risk involved when you are working with the lighter sanders, and you might still take a few nicks out of the deck’s surface, but the chances are still much lower. It is imperative to first work out the specifics of the job, and then decide on the type of sander to use for the job at hand.

What Are You Willing to Pay?

Buying a machine like this is certainly not cheap, but it is undoubtedly a powerful tool, which most of us would consider a worthwhile investment. The truth is that you are getting the best value for your money these days, but that does not mean that you are not deserving of more. However, depending on your price range and the application you will be doing, you should be able to choose from a variety of orbital or belt sanders.

Resurfacing your deck is usually necessary every year, making it a wise investment to have within your tool collection. You should first consider the size of the deck, as well as the distance from the power supply. Will you only be using your sander for the refinishing of your deck? Or will you be utilizing it for a variety of jobs? For obvious reasons, if you are simply using the sander to refinish a small deck, then you will not have to buy the most expensive sander that is used for industrial jobs, but rather one that will be much more affordable and easier to use for the average person without as much skill.

If the deck you need to refinish is quite large, you may benefit from a larger industrial machine typically used for construction jobs. The type of sander you purchase should also be suited for your preferred ergonomics. If you have a sore back, you will want one where you do not have to bend down as much.

Do You Need Variable Speed?

The speed needed to complete a job is variable between the size of the deck, the type of wood used to create the deck, as well as what finishes you are removing from the surface of the deck. Sometimes all you need is fine-grit sandpaper on a low-speed setting, but occasionally (a lot of the time) you will need a machine with more power. Some orbit sanders only have a one-speed setting, but usually, you will find they have a selection of speeds from low to high.

Different sanding speeds are suited to various tasks. The railings will appreciate a lower seed setting because it will allow you more control over where the sander is directed. The higher speeds are better when you are sanding down large boards, or extremely long planks, like for the decking in question.

This is not to say that only having a one-speed setting is impossible to work with, no matter the type of job you need the sander for. The right amount of practice will facilitate the skill that you need to use the single-speed sanders with ease. That way, you will become more accustomed to the amount of pressure you can apply to the wood without damaging the surface.

Do You Need Dust Collection?

If you haven’t already figured it out, buying a sander is very similar to deciding on the additional features you want your future car to have. Engine size, manual or electric windows, rear sensors are very helpful when parking in tight spaces. Each is equally as convenient and once you get accustomed to them, it is hard to downgrade. The same can be said for your deck sander. What other features are included in the one you are thinking of purchasing? Is there an option for different speeds that will enable you to perform more versatile tasks? Or maybe the brush attached to the bottom helps to brush away the dust that is created by the sanding?

One of the more helpful features now increasingly common in the various designs by different manufacturers is an attached container to collect the dust created by the sanding machine so that it does not fall to the floor or suspend itself in mid-air, waiting to be inhaled. This makes the cleanup process that much quicker because there is less sawdust lying on the ground, and you can simply dispose the sawdust directly into the trash.

Do You Need Less Noise?

Some people are not a fan of loud machinery, and the best sander for a deck for them would be a silent one, or they might resort to a manual sanding process. The excessive and repetitive noise can be torturous for some ears, and the neighbors are more likely to complain if you have a workshop set up in your backyard. Luckily, the orbital deck sanders, which have become increasingly popular because of their easy design and lack of vibration. Some of them have been made to be less noisy as well, which we would advise using if you are sensitive to loud noises. There are noise and emissions regulations that the manufacturers have to follow to have their design approved for production.

There are many disadvantages and advantages that you can expect from the various electric sanders. The right one will be dependent on what you want to do with it. We hope that this tutorial has shed some light so that you can make a more informed decision when purchasing your electric deck sander. Have fun on this new adventure of learning a new skill, and enjoy the professional feel that your deck shall encompass.

Frequently Asked Questions

How Do I Sand a Deck?

The best way to sand a deck is to start by cleaning it. Once it has dried, you can then start to sand it down. This way you will get a smooth and even finish. Repeat the process if needed for the single board, then move on to the rest.

How Strong Must the Sandpaper Be for Deck Sanding?

The strength of the sandpaper used will depend on what you are using it for. If you are removing an old coat of paint then we would recommend very coarse sandpaper. If you are simply smoothing out the surface, then you only need slightly coarse grit sandpaper.

Is It Worth Sanding a Deck?

Everything that is man-made will need a bit of maintenance from time to time. To maintain a deck, you will need to sand it down so that you can add more treatment to the surface. This will extend the longevity of your deck, saving you time and money.