The most common deck board fastener options for wood decking is nails or screws. They both have their strengths and weaknesses but they are not equal in their performance. When attaching deck boards, screws or nails is not a matter of, but a critical decision for building a deck to be enjoyed for years.
It is always better to screw down deck boards. Nailing down decking is only setting yourself up for problems in the future. The single biggest reason never to nail down decking boards is nails will pop over time, ripping your socks and ruining your deck.
Years ago, I was working up in the trusses of a house I was framing. Another subcontractor was working down below, building a deck. Hearing his nail gun, looking down, I could see he was nailing the decking down. I yelled down to him, “you ought to be ashamed of yourself, nailing decking down!” Not much has changed, I still think it is shameful to nail down decking, but I have grown in my reasons why.
If for no other reasons, screw-down your decking to avoid nailing popping. But as I said over the years, I have learned many more reasons to screw down your decking. Here are a few reasons to screw deck boards and arguments to nail decking.
Screwing down deck boards avoids nail popping
I remember my first year in carpentry school, all keen to learn and understand everything about the trade. Then this question popped up in one of my open book tests.
How do you stop nail popping in drywall?
I scrambled through all my notes and literature. There must be some special technic to stop nails from popping, but nothing the more frantically I searched, the less I knew. How in the world can use stop nails from popping? Till finally, in desperation, I sheepishly guessed and waited for the computer to correct my test. I will never forget the answer, “Don’t use nails.”
Decking is not drywall, but the principles are the same. If you want to avoid those nasty nail head popping up on your deck, don’t use nails. Screw’s threads are superior to nails in their tensile holding power — the threads cutting into the wood fibres holding fast through all seasons.
Nails are just no match for hygroscopic material like wood. Hygroscopic is a fancy word for material that changes size with water. When it rains, wood decking swells. When the sun comes out and dries, it shrinks. The swelling and shrinking acting like a pry bar slowing pushing the nail head out of the decking.
The difference in actions is from the installation. Nails are driven into wood, piercing between the wood, where screws are twisted into the wood, gripping unto the wood around it, maximizing its strength.
Deck Screws are Engineered to Win
Isn’t it amazing how far the pros can drive their golf balls? In the last few years, it seems that they are consistently driving farther than ever before. No offence to the pro’s skills but part of it is engineering. The science that goes into modern clubs is literally a game-changer. Designed to direct the swing and energy better than ever before.
Screw Heads are Better For Decking
The same is with the technology and design of decking screws. Decking screws are designed to hold decking better than nails, with the focus more on durability then installation. Let’s start by comparing a nail’s head and a deck screw. A nail head is flat, like a plate lying on top of the decking. When the decking swells, the pressure has no place to go but push against the nailhead, pushing it up.
Deck screw bulge heads are designed as a cone. The bulge head allowing swelling decking to move pass without pushing on the head while still holding the decking. The screws remaining intact, as the decking swells around the head and then shrinks back into place. The cone-shaped bulge head, with an increasing head increase hold as the wood pushes against the head, ensuring that the decking stays in place while still not allowing the wood to push out the screw.
Screws Are Designed For Decking Seasonal Changes
Moving further down the screw to a smooth 1 ¼” (32mm) shank (no thread). The smooth shank allows the decking to expand and shrink with the seasons without tearing apart the decking. Further, ensuring that the screws stay securely in the joist, while the decking expands and contracts.
With even better-designed deck screws like the Hillman 42482 Power Pro Premium Exterior Wood Screw which can be ordered from Amazon, have cross-cut threads and a wood biting cut point to help prevent decking splitting when driving the screws in — decreasing the chances of splitting the decking while holding it securely to the joist.
Just a little aside, a little trick I learned from Jeff from Home RenoVision DIY when screwing near the end of your board, spin it backwards a few seconds heating up the screw tip and then screw it in. It helps a regular screw to screw through decking all without splitting it. Next time your screw down a deck, give it a try. You will be amazed.
Screws Hold the Edge Of the Deck Board Better
Screwing down decking boards also helps to minimize cupping. The tensile strength of the screws holding down the edge of the decking, preventing them from curling up. Preventing cupping and extending the decking’s life.
Even with all these reasons to use screws, there are some objections to screwing down decking. Let’s discuss these objections to see if they are valid.
Reasons to Nail Deck Boards
Nails Cost less.
Screws will cost around 25% more than nails. For a 5oo square foot deck nails will cost around $60 and screws $73. The difference is about the same as one piece of treated decking. If screws prevent one board from being damaged, they have paid for themselves.
Nails are stronger.
Screws are brittle and snap easily. This is partially true. For shear strength nails are made of much stronger, being a pliable material. Nail still holding together while being completely bent over. One quick hit with a hammer and screws will snap. Shear strength is very important for horizontal fastenings, like nailing joist blocks together. Or attaching the rim to the joist ends, very important. But decking doesn’t need shear strength. It needs tensile strength, holding it to the joist.
So, yes, for the decking substructure nails are often the better pick, providing greater strength but for decking screws are the winner. Nail together, screw down, that how I see it.
Nailing is faster then Screwing.
Yes, that is entirely true. That’s the excuss that deck builder gave me when I call him out. He didn’t have time to screw the decking down. Well, if this is a race and only time matter, then grab your spiker and let her rip. Slap it together as fast as you can.
But, if your building a deck to be enjoyed for years. If the deck is about more, then how quickly it can be built. Spend the extra time and screw it down. Screws for the many reasons listed above will give you a better deck for just a few more hours of work. A moment on the drill, a lifetime of deck enjoyment. A well-built deck, is a better deck.
Picking the Right Screws for Decking.
If you are going to pay the extra money and time to screw the deck boards, make sure you are using the right ones. Wood decking is commonly treated with (ACQ) and (CA) to prevent fungi and rot. Great for preserving wood but corrosive on fasteners. All deck screws need to be organic polymer coating or stainless steel to prevent corrosion. Stainless steel is the better of the two but is costly.
One of the advantages of polymer-coated screws is that they come in different colours, often coinciding with decking colours. Brown for copper treated decking, green for green treated decking helping to blend the screws with the decking. But the most important thing is that they must be treated to prevent corrosion.
Now that you have the right screws and you are convinced that it is better to screw deck boards, then nail, let’s just go over a few questions to screw better.
Should you pre-drill deck boards?
Only the ends of decking will need to be pre-drill if you are working with softwoods, like cedar or pine. When working with hardwood decking like Ipe, predrilling is required for all screws.
The main reason for predrilling decking boards at the end is to prevent splitting. Predrilling removes material to allow the screw to be driven without pushing the wood out and splitting the decking.
What size of hole should you drill for a screw?
A screw hole should be about 1/16” (2mm) smaller than the screw. Big enough to allow the screw to pass through without putting pressure and the wood. But small enough for the screw threads have material to grab. Most #8 deck screws use a 1/8” (3mm) pilot hole.
How far should screw decking be from the edge?
Ideally, decking should be screwed 1” (25mm) from the decking edge, two screws per joist. Close enough to the edge to prevent cupping but far enough away from the edge as not to split the decking. You do not need to measure each screw but strive to be consistent throughout the deck. Just for appearance’s sake.
If a screw location happens to be on a knot of the decking, grab that handy drill and predrill the hole. Knots are extremely dense and can’t be screwed through. Also, you will not be able to countersink screws in a knot without predrilling.
How many screws will I need for my deck?
A deck with joist 16” (400mm) on centre, with 5 ½” (140mm) decking, will take about 350 screws per 100 square feet of deck. A 500 square foot deck will need about 1750 screws. I always like to buy a few extra because you will drop of few between deck boards and an extra unaccounted-for joist will come into play.
Should you countersink deck screws?
Yes, face screwed decking should be countersunk. Just slightly below the decks surface an 1/8” (3mm) or so.
Why do you countersink a screw?
Screws are countersunk for two reasons. The first is not to snag your socks as you walk on the deck. Not cool, not cool at all, especially if you are barefoot. The second reason is equally important is to account for the expansion and contraction of the decking. The advantages of screws are that they do not move up and down. Remaining at the level, they were driven at. But that means during the hot summer months when the decking dries out and shrinks. If you don’t countersink the screws, then all the screws will be sitting high, back to snagging your feet on those beautiful summer days on your deck.
What is the best way to fasten deck boards?
Face screwing is better than nailing. Edge screwing is better than face screwing. I have become a big fan of edge screwing decking for several reasons.
- a cleaner appearance
- no rotting pools on decking
- no snagging heads
- Larger holding surface
The best system I have come across for edge screwing is Camo. Camo conveniently holds the screw for consistent and easier installation. Come with a pre-set decking spacer, helping to provide a consistent gap. Allowing you to gap either 3/16”, 1/8” or flush/no gap depending on the tool.