How To Lay Deck Boards: Essential Guide

When building my last deck, one of the major challenges I had was finding a way to lay my wood deck boards so that it looked good but still maintained the integrity of the structure. Once I discovered how to lay deck boards properly, my deck ended up looking good.

Deck boards should sit 1 ½” off the edge of each side of your deck. Use your straightest deck board and lay it first across the deck’s front edge, opposite your house. Each board should have a ⅛” gap. All deck board should end on a joist, making sure to stagger deck board ends.

While laying deck boards might seem easy and quick, you’ll want to take your time and do it right. One small mistake could result in you having to remove all the deck boards later to fix that extra-wide gap or crooked deck board.

In this guide, we’ll go over all the important aspects about the layout and installation of wood deck boards.

How to lay deck boards

How To Lay Deck Boards: Step by Step

Before you even dig a post hole or purchase a piece of lumber for your deck, you should plan exactly where and how you will lay your deck boards. From the planning stage to installation, laying wood deck boards takes careful consideration.

In this section, we’ll go over each step you need to take to install wood deck boards.

Decide on Deck Boards Layout

How to install deck boards

When deciding on a deck board layout, you are constricted to deck board lengths that can be purchased at the store. Standard treated 5/4” wooded deck boards can come in lengths up to 20’, with lengths of 18’, 16’, 12’, 10’, and 8’ also widely available.

Remember that deck boards are 6” wide, typically, and that your joists should be no more than 16” apart if you are using 5/4” deck boards, and no more than 12” apart if you intend to place your deck boards diagonally. You can space your joists 24” apart if using 2×6 lumber.

The layout of your wood deck boards will determine how you will frame your deck. If you plan to orient your deck boards parallel to your home, then the joists will run perpendicular to your house. Your main deck beam will also be parallel to your home.

Making your deck boards perpendicular to the house will result in joists parallel to the house and beams that also run perpendicular to the house.

Naturally, you’d like your deck boards to span the entire width of your deck to avoid gaps. Aesthetically it will also look much nicer; therefore, you should give most of your consideration to ensuring you can acquire deck boards that can run that expanse.

If you have a really large deck and cannot purchase deck boards that are as long as your deck, considering altering your design to run the deck boards in the other direction. If your deck is more than 20” wide and long, you can use a raised joist in the center to divide the deck in half, allowing you to place your deck boards halfway while achieving a flush look without deck board ends butting up against each other.

Choose the Type of Decking Boards

When it comes to choosing wood decking, you’ll find that your local big box stores carry two kinds: pressure treated and western red cedar.

Both come in either 5/4” or 2” thickness. A deck built with 2×6 deck boards will feel more solid; however the cost is substantially more. Also, consider that 2×6 decking is near twice the weight of 5/4” decking, so your footings, joists and beam must be designed to account for the added weight.

Also, 2×6 deck boards have a standard, straight edges. 5/4” deck boards have rounded edges for a more finished look. Remember that you’ll also need longer fasteners for 2×6 deck boards, whereas you can use 2” screws for 5/4” decking.

I recommend 5/4” deck boards. They are cheaper, easier to install since they are lighter, require smaller fasteners, and have a nicer appearance than 2×6 lumber.

If you opt to use cedar deck boards, expect to pay anywhere from 1.5 to 2 times the cost compared to standard, pressure-treated decking of the same dimension.

No matter which type of lumber you choose, your deck boards should be installed so that the grain cups downward. What does that mean? Look at the cut end of a deck board. You’ll notice the wood grain “crowns” in a certain direction.

Make sure the open end of the crown faces down. Why? Over time wood warps as it dries, and it will warp in the direction of the grain. So if the grain faces downward (meaning the open end of the cup faces down on the end grain), then the wood will naturally warp that way. This is good because it means water will be able to run off easily and not pool on the surface of the deck board.

Nails or Screws

Screws are better than nails when installing deck boards. While building code dictates the use of nails for framing members in a deck, screws are more appropriate for decking boards.

When it comes to holding power, a screw is much more effective in restricting lateral – side to side – movement than a nail. The threads of a screw give it more surface area than a nail, which allows it to grab the wood better than a nail.

Nails are better suited to withstand shear forces – up and down – rather than lateral force. The thickness of a nail is why nails are mandated for use in deck framing members instead of deck screws.

Therefore, use screws when installing your deck boards. Screws can also be faster to install, without the risk of damaging your deck board like you could if you used nails and a hammer.

Use of 2” deck screws with 5/4” deck boards is appropriate, and 2 ½” screws with 2×6 deck boards. However, there are a couple of different options for screw installation, which we’ll look at below.

Regular Deck Screws

Regular deck screws come in different lengths and diameters. Typically you’ll want a deck screw that is at least a ½” longer than the lumber you are fastening. So if you are using 2×6 deck boards, you’ll want a 2 ½” length deck screw, at a minimum.

Numbers on a box of screws also indicate the diameter – #8 deck screws indicate that the diameter is roughly 4mm. #10 deck screws would be slightly wider, and so on. A #8 x 2 ½” deck screw is sufficient for 5/4” deck boards. Larger diameter screws would require pre-drilling with a larger drill bit, as the larger screws will crack your deck boards in a hurry without a pre-drilled hole.

The downside to using regular deck screws is that you either have to pre-drill each hole or live with the fact that you may crack some of your deck boards if you don’t pre-drill. If you get your deck boards from a new batch of store-delivered pressure-treated lumber, they might still be wet enough to get away without pre-drilling. But if you aren’t sure, you’ve got to pre-drill.

Another drawback to using regular deck screws is that it is easy to plunge the screw too deep into the deck board. You want the screw to sit flush with the board. Any further will result in water standing in the screw hole, which will speed up the deterioration of the board itself.

Remember that each deck board should have two screws at each joist. Ideally, try and space them about an inch from each edge.

Hidden Deck Screws

Installing deck boards

Hidden deck screws are just that – hidden. They install with the help of a jig that is purchased along with the screws that fit into the jig. The jig is an angled, handheld device that holds the screw at an angle, allow you to drill into the side of your deck board and into the joist beneath.

I prefer the Camo Hidden Fastener system. The handheld jig affixes to the width of any size of the deck board. It allows you to place a screw at each end of the jig and fasten both sides of the board. The low profile head of the camo screws makes them nearly impossible to detect from above.

The jig also automatically spaces each board 3/16” apart, so you don’t’ have to use spacers or space each deck board with a nail. This speeds up deck board installation.

Best of all, you don’t have to pre-drill with Camo fasteners. The design of the screw results in very little tear-out.

On the other hand, the Camo system is more expensive than simply using deck screws. A box of Camo screws runs about three times the cost of regular deck screws. The jig itself is an added cost.

Waterproof Deck Joists

Laying deck boards

Before installing your deck boards, you’ll also want to consider using joist tape on top of your joists. What is a joist tape? It is a waterproof tape that protects the top of your joists from rotting due to moisture damage.

When moisture runs off a deck board, it can get trapped between the underside of the deck board and the top of the joist. Since these areas receive zero sun, they stay wet. Wet wood eventually rots – even pressure treated wood. Joist tape can prevent your joists from rotting and protect the structural integrity of the deck.

Stagger Deck Boards

Staggering Deck Boards

When laying your deck boards, you’ll want to stagger the boards as you lay them, if necessary. Staggering the boards will increase the aesthetic appeal of the deck while minimizing the number of screws in one particular joist.

To stagger your deck boards, lay the first full deck board down, then lay the next one down, making sure it butts up against the full board. Cut this piece to fit, then take the other half of the board you didn’t use and begin your second row of decking with it besides the first full piece.

Deck Boards Overhang

Deck boards should overhang joists by 1 ½” on all sides of the deck that are not against a structure. Both ends of your deck boards will end on a joist. However, you want each side to overhang to protect the joists. This ensures moisture will run off the deck onto the ground instead of on top of the deck framing.

The front of your deck should have 1.5” of deck board width beyond the joists. This protects the joist ends. For safety, a deck board running lengthwise cannot overhang joists by more than 1.5”.

Recommended Spacing Between Deck Boards

Spacing between decking boards

Spacing between deck boards should be ⅛”. You can purchase deck board spacers that affix to the boards – they can be plastic or metal and make spacing boards simple. Or you can use an 8d nail, which is around ⅛” in diameter.

If you are using wet lumber, install your deck boards with no space. Over time the lumber will dry, creating a gap between the deck boards.

Whichever way you choose to space your deck boards, make sure you use the same spacers for the entire installation. A consistent deck board spacing is arguably one of the most important visuals on a deck.

Using a device like the CAMO Marksman Pro makes spacing deck boards simple, and you can screw your deck board in while you space the board, making your deck board installation faster. The Marksman automatically spaces the board 3/16” apart.

Install Decking Boards

How to lay decking boards

When it comes time to install your deck boards, there are a few tools you’ll need that are indispensable to the project:

  • Miter saw
  • Cordless drill
  • Impact Driver
  • Deck board spacers or Camo Marksman Pro
  • Circular saw
  • Deck board straightener

You’ll absolutely require the deck board straightener. Crow bars also work, particularly long pry bars, but the deck wrench is designed to bend deck boards into place as it locks onto the deck framing. It is very rare to install deck boards and not have at least one or two that are very warped.

Pro Tip: Get a new blade for your miter saw. This will reduce the amount of cut-out on your deck board ends, making the butt joints look smoother and less noticeable. A decent blade will last your entire deck project and beyond, so it’s a small price to pay for a nice-looking deck.

Let’s take a closer look at how to install wood deck boards on a deck.

If you are running deck boards parallel to your house, then you’ll lay your first deck board next to your house and work away from the house. If your joists are parallel to your house, then your deck boards will be perpendicular to your home. In that case, choose the more visible, higher traffic end of your deck to start on, if possible.

Your first deck board should be ¼” from your siding. Overhang your first deck board over the rim joist, which the other end centered on a joist. If your deck boards span the entirety of your deck, make sure both sides overlap the rim joists on either side by at least 1 ½”.

Before you screw your deck board in the joists, be sure you’ve laid your deck boards bark side down. If you look at the end grain of each deck board, it either “smiles” or “frowns”. You want your deck boards to “smile”. Why? As the wood dries, it will warp in the direction opposite of the grain. Thus, if the grain is facing upwards, over time, the deck board will cup downward, shedding moisture more easily.

After you’ve oriented your deck boards and placed the first one ¼” from your house, it’s time to screw in your first deck board. Install two screws on every joist, being sure to place each screw about 1” from either side of your deck board. If you are using 5/4” deck boards, use #8 x 2” deck screws. If you are using 2×6 lumber, use #8 x 2.5” deck screws.

Next, it’s time to cut your second deck board. Assuming the first was not long enough to span the entire width of your deck, cut your second piece to fit between the butt end of your first deck board and at least 1.5” past the opposite rim joist. Make sure your next deck board is still ¼” from your house, and screw it in. Your deck board butt ends should be centered on the joist to allow ample room for the four screws it will hold – 2 from each butt end.

Take the deck board piece you didn’t use from your previous cut and use it as the first deck board for your next row. You may have to trim it with a miter saw to fit it exactly on a joist. You want to make sure that this piece terminates one joist before the joist where your first deck board terminated. Before you fasten the board, ensure it is ⅛” from the first row of deck boards. Use deck board spacers or the Camo Marksman Pro system to ensure even spacing. If your boards are wet, then do not use a space.

Use the same process of cutting the deck boards, then using their cut ends to form your next row, ensuring butt ends are one joist away from the butt ends of the previous row. This will give you a random deck board spacing layout that will look nice, aesthetically. Remember to always use two screws per joist, and to overlap your deck boards at least 1.5” beyond the rim joists.

When you get to the far end of your deck, make sure the width of your last deck board is at least 1.5” beyond the ends of the joists, in addition to either side.

You now need to trim your deck boards to 1.5” beyond the deck framing on all sides, not abutting against a structure. On the deck board furthest away from the house, measure 1.5” beyond the rim joist. Make a mark on the top of your deck board. Do the same on the other end, by your house. Use a chalk line to make a line between the two points. Then use a circular saw to trim the ends of your deck boards. Repeat on the opposite side. Use a jigsaw to cut the last bit on either end, as the house won’t allow your circular saw to cut the last couple of inches.

Finally, you may need to trim the length of your final deck board. If the width of our last deck board is further than 1.5” beyond the ends of your joists, then you need to make a cut. Just as you did with the deck board ends, measure 1.5” beyond the rim joist on the end of your last deck board. Make a mark. Do the same on the other end of the same deck board. Use a chalk line, make your line, and cut with the circular saw.

Depending on your design, you might need to cut openings for deck railing posts. If so, then you’ll first need to measure exactly where they go. Once you’ve done that, measure and use a pencil to denote on the deck boards where the railing posts are. Use a drill with a small spade bit, such as ¼”, and make a hole inside the mark that indicates where the railing post will go. This will allow you to get your jigsaw into position to cut out a square from your deck boards where the deck railing post will go.

Which way should my decking go

Make sure you give ⅛” or 3/16” on all sides of the deck railing post to allow for ease of installation and shifting in case your railing posts happen to shift slightly over time. This will prevent the deck boards from cracking.

Conclusion

There are few things more satisfying than installing brand new deck boards. A properly installed deck surface can look fantastic, as long as you take the time to plan the layout, account for board orientation, and properly space your deck boards.

Thanks for taking the time to read this article. Hopefully, you were able to get a few tips or tricks that will improve your next deck board installation.

If you have any suggestions for improving this article or tips and tricks that I missed, don’t hesitate to drop me a line – I’d love to hear your feedback!

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