What Size Nails Are Best for Deck Boards?

It can be a lot of fun designing a deck, from the shape to the color to the thickness of the wood. However, building a deck involves more than just your personal preferences. If you want to ensure that your decking will last for as long as possible and be safe to use, then it is essential to take the time to ensure that you have the right tools and equipment. That said, what size nails for deck boards should you use?

There’s no quick or easy answer to this question – however, depending on the thickness of wood, three-and-a quarter lengths should be more than enough.

However, this can vary depending on your project, too – so keep reading, and we will fill you in on what you need to know.


Why is finding the right size nails essential for decking? 

You will likely be expecting your deck to stay with you for years to come, and providing you set it up properly and look after it, there’s no reason why it won’t. However, ensuring that you have the perfect tools to use to set up your deck will make all the difference. 

Having the right nails for your deck will better ensure its structural integrity, thus better ensuring its longevity and, most of all, the safety of those that use it.  

Which size nails are best for deck boards?

Just as you need to find the right size of nails for a baseboard in the home, the same applies to any deck boards outside, too.

The right nails for your deck board will depend on the thickness of the planks of wood. The nails need to be thick and strong enough to penetrate the wood, thus holding it to other elements to ensure its strength and integrity. 

The general math used to calculate an ideal nail size for a deck board is that at least an inch of your nail should enter the decking joist. As mentioned, around three-and-quarter inches will be enough for most boards. However, experts will also suggest that you use an equivalent to a 10d, or three inch nail, for decking at around four to five inches.

Beyond that, you should ideally go up as far as 16d, or three-and-a-half. Three, crucially, is the magic number when it comes to deck board nailing.

Nail types for deck boards

Ideally, you’ll need to use nails that work best with the elements. Some wood can also subject metal to corrosion, which is why opting for a stainless steel or galvanized nail will be your best choice. 

Different types of wood will also demand different nails, too. For example, wood such as plywood will likely need spiral nails – but again, you can’t really do much wrong with hot dipped or galvanized nails for outdoor projects.

The reason why it’s worth using nails such as spiral types is for the simple fact that you may lose grip and fastening over time with a smooth nail choice. So, don’t take the risk – and go for some extra grip!

For treated lumber, you’re likely going to need a stainless steel nail to, again, avoid corrosion. Therefore, you need to be especially careful with the type of nail you put into your boards.

You’ll also find you need different types of nails for deck framing, too. It’s in this circumstance where you will need to focus more on the length of your nails than anything else. Generally, 10d or three inch nails are ideal, once again.

What nail gun to use for decking works best?

It’s entirely possible to start nailing down your decking with an automated nailer or gun – and on the whole, a framing gun is your best choice. In our guide to using a nail gun on decking, we run through everything you need to know.

Are nails or screws better for deck boards?

There is split opinion on what may work best for deck boards over time. Nails do give a strong fastening on the whole, but screws, while a little more expensive, are said to offer more endurance. That said, it may also be easier for you to use a nail gun instead of a drill and a screwdriver.


Although something as simple as nails may not seem as though they can make a huge difference, they are essential for your deck’s integrity, strength, and security. Choosing nails should not be based on budget or personal preference and should only refer to what is right for your wood type and plank thickness.

Using the right nails really will mean the difference between a long-lasting, safe deck and an accident waiting to happen. Therefore, make sure to choose the appropriate fasteners, nails and even nail guns for this type of job – and if you are ever unsure, make a point to consult a woodworking expert, or to check the manual for any nailer you may be using.

Just be sure to use a nail gun that’s built for decking – the best nail gun for paneling may not always be the top choice!