3 Ways to Make Shiplap
When installing shiplap horizontally on a wall, use coins to set a consistent gap that allows for seasonal expansion and contraction. Nail into studs through the lapped joint, using a 15- or 16-gauge finish nail. If you’d prefer to avoid exposed nails, you can either set them and fill the nail holes before painting or finishing, or use construction adhesive on the lap joint and nail only the top (hidden) tongue.
Popularized by home-renovation TV shows, shiplap is enjoying a renaissance as a wallcovering, but has always been a sound choice for door panels or backs for cabinets and bookcases. You can easily make your own with any of the three methods shown here, and even dress up the joint with routed profiles.
So, what is shiplap?
Although we could find no credible sources tracing its origin to actual ships, shiplap joinery has commonly been used to create a weather-resistant wallcovering. When shiplap boards are nailed in place rather than glued, the overlapping rabbets maintain lapped coverage as the boards shrink and swell because of seasonal humidity changes.
Your board width dictates the dimensions of the mating rabbets: For workpieces 4" or narrower, a 1⁄2 " rabbet suffices; for boards between 4–8" wide, make the rabbet 3⁄4 " wide.
Begin by jointing and planing all stock and a few test pieces flat, square, and to consistent thickness. Then, rip the pieces to final width on the tablesaw. You can crosscut to final length now or after milling the shiplap edges. Determine the good/front face of each board and mark it. Then, cut the joinery using one of the following methods.
Lapping at the tablesaw
Install on your saw a stacked-dado set a little wider than your planned rabbet so you can cut each rabbet in one pass. To prevent cutting into your saw’s rip fence, attach an auxiliary fence, positioned slightly over the stack. Raise the spinning stack until you reach the desired height. Make test cuts in the extra pieces you prepared. If your saw or dado set won’t allow for a wide-enough stack, simply cut the rabbet in two passes.
Rabbet with a router
Although you can rout a rabbet with a straight bit and edge guide, a dedicated rabbeting bit makes the task virtually foolproof. Set the rabbet width by installing the appropriate guide bearing for the width of the desired rabbet. Installing an offset base on your router helps prevent the router from tipping and creating uneven cuts. After getting a perfect fit on your test pieces, rout all rabbets on the keeper boards.
Take it to the router table
You can also use a rabbeting bit on a router table—just make sure the fence faces align flush with the bearing. But with the fence as a guide, you can use any straight or spiral bit; we prefer downcut spiral bits on the router table for the cleanest cuts.
Use featherboards as shown above to ensure consistent rabbets. For rabbets wider than your bit’s diameter, rout the rabbet in two passes, moving the fence away from the bit after routing the first pass on all pieces.
Tips for installing shiplap
Secure shiplap with brads or finish nails—no glue. Brads or nails will flex slightly, enough to allow for the expansion and contraction of each board.