Installing Deck Boards
Don’t cut corners when it comes to choosing your decking material. This surface is the business side of your deck. It gets the most use and takes the most abuse. If your lumber and decking were not pretreated, consider applying a water repellent now. At this point, you can coat the tops of the joists and reach other parts of the deck that may be inaccessible later. It’s also a good idea to coat both sides of the deck boards before installing them.
Tools: Circular saw, hammer or screw gun or drill equipped to drive screws, chalk line or mason’s line.
1. Choose your decking. Building centers generally carry several choices of material for decking. Nominal 6-inch boards are the most popular width. Boards wider than 6 inches tend to warp too much, while narrower boards take longer to install. Standard 2x6 boards are 1 1/2 inches thick and are the least expensive. Five quarter (5/4 inch) boards are about 1 inch thick and cost a little more. However, they are often a better grade of wood and are available with a radius edge (rounded edge). Decking also is available in plastic and wood-plastic composites. The process for installation is the same as wood decking. These products cost more, but they require little long-term maintenance.
2. Select deck board fasteners. Several products now are available to fasten deck boards to joists without nailing or screwing through the surface of the decking. These fasteners are concealed between boards. That means a better-looking deck and less rotting around fasteners. These fasteners, however, make it more difficult to remove and replace individual boards at a later date. They also cost more than nails or screws and installation is more time-consuming. You may not be able to find all the options shown here at your home center, but one or two should be available. Galvanized or anodized deck screws hold the best and are relatively quick to install. Galvanized nails are faster to install, particularly if you use a power nailer, but can pop out over time.
Which Side Up? A rule of thumb is to install decking boards with the bark side up. It is thought this allows water to drain off if the board cups. However, studies show decking installed with the bark side down is less likely to develop splits in the surface. The best advice is to make sure the wood is dry and install the best looking side up. For added prevention, apply water repellent every year.
3. Install starter board. Your job will proceed much easier if you install the first board as straight and as square as possible. On both end joists, measure out from the house the width of one decking board (5 1/2 inches) plus 1/4 inch for a drainage gap. Mark the joists, then snap a chalk line or run a mason’s line between them. Set the first decking board along this line. For best results, use the straightest board you can find for the starter board.
Scatter the Boards - Making a trip to your lumber pile every time you need another decking board wastes time and energy. Instead, carry a number of decking boards to the deck and scatter them across the joists. As you begin laying the decking, you can use the loose boards as a working platform, particularly when you are right up against the house. Later you can position your reserve boards so each can be pulled quickly into place for fastening.
4. Stagger joints. On a narrow deck, you may not have any butt joints between decking boards. However, on our 20-foot-wide basic deck, we planned for the joints by installing two sets of double joists. This requires the use of one long and one short board in each row of decking, with the joints staggered on the double joists. Leave a 1/4 inch gap between board ends to allow for water drainage through the decking and the double joist.
5. Leave a space between boards. Deck boards need to have a gap between them to allow water and dirt to fall through. Bear in mind that the wood shrinks over time as it continues to dry. Use a 16d common nail as a spacer.
6. Use proper fastening methods. Decking can be installed with decking screws, nails (16d nails for 2x decking, 10d nails for 5/4 decking), or special concealed fasteners. Use two nails or screws at each joist crossing, about 1 inch from each side of the board. Whether using nails or screws, drill angled pilot holes at the ends of boards to prevent splits. Drive heads of nails flush with the decking. As the wood dries, drive them deeper. If you use a power nailer, adjust the depth so the nail heads are slightly below the surface of the decking board.
7. Keep it straight. Straighten crooked boards as you fasten them. Use a utility-grade chisel or a pry bar to force warped boards into alignment. You can do this by yourself, but the process is much simpler if you lever the decking while a helper drives in the fasteners. On severely warped boards, you may have to repeat this from one joist to the next. Check for straightness every few rows by measuring from the header joist. If you’re significantly out of true, hide the mistake by making small adjustments in the spacing gap over several of the next rows rather than all at once.
Planning an Overhang - Give some thought to the amount of overhang you want on your finished deck. An overhang isn’t necessary. You can cut the decking flush with the joists. However, you may be happier with the appearance of your deck if you let the decking extend beyond the edges on each side. A 1- to 2-inch overhang is most common and gives a finished appearance to your deck. As you install your decking, let the boards overhang the end joists (see below). They will be cut to length after the entire decking surface is installed.
8. Plan ahead. When you get down to the last three or four rows of decking, start planning ahead for the last row. Chances are that full-width boards won’t fit perfectly, and you should avoid installing one narrow board at the end. Instead, rip small amounts off the last several rows of boards while maintaining the same gap between boards. Let the end row overhang the header joist by the same amount as the overhang on the sides.
9. Trim the edges. When you’ve installed all the decking, snap a chalk line along the edges to mark the intended cutoff line. Check that the overhang is the same on all three sides. Set the blade of the circular saw so it just clears the bottom of the decking. Carefully cut the decking by following the chalk line. If you are concerned about cutting a straight line, tack a long, straight board on the decking as a saw guide.
10. Round the edges. To prevent the wood from splintering and to enhance the beauty of your deck, round the sharp edges of the decking. Use a router equipped with a round-over bit.