Home Improvement Ideas Home Remodeling Carpentry How to Make a Scarf Joint Scarf joints help conceal the seam in your molding. Before remodeling, learn how to make one. By Caitlin Sole Caitlin Sole Caitlin Sole is the senior home editor at BHG. She is a writer and editor with nearly a decade of interior design expertise. She has vast experience with digital media, including SEO, photo shoot production, video production, eCommerce content, print collaboration, and custom sales content. Learn about BHG's Editorial Process Updated on March 7, 2024 Trending Videos Close this video player For the best appearance, moldings should run in one continuous strip from one corner of the room to the next. But a joint becomes unavoidable when the room is longer than your molding. The solution is a scarf joint to make the seam as invisible as possible. Made with 45-degree cuts, this seam won't take any attention away from the beautiful room it sits in. Learn how to make one for your home makeover using our helpful tips below. 16 Crown Molding Ideas That Add Character and Charm What You'll Need Equipment / Tools Stud finder Pencil Miter saw Hammer Drill Materials Tape Nails Sandpaper Glue Touch-up paint Instructions How to Make a Scarf Joint Find a Location If possible, locate the joint where a bed, bookcase, or other large piece of furniture will hide it. That way, you'll only see the seam on a moving day. Behind a door is another good spot, but be careful of positioning a joint too close to a corner. A seam closer than 16 inches from a corner may look as if you're fixing a mistake—not making a planned extension. Select the location for the scarf joint, positioning it over a stud, if possible. Mark the stud's edges and centerline onto a piece of tape applied to the wall. How to Find a Stud in the Wall Without a Stud Finder Mark the Cut Line Fit the end of one molding piece into a corner, then mark the seam cutting line. In this example, the corner at the right is fitted first. To help your cutting, mark diagonally across your molding piece. Make the First Cut Make the first half of the scarf joint with a 45-degree miter cut that opens away from the wall. Nail this piece to the wall at the other stud locations along the wall. The 8 Best Miter Saws of 2024 Make a Second Cut Fit the end of the second molding strip into its corner, and mark the location of its scarf joint. Notice that the miter runs opposite to the cut in the first piece you installed. Make several cuts to sneak up to a perfect fit. Drill Pilot Holes Using a cordless drill, drill pilot holes for the nails that will secure the seam and hold the molding to the wall. Don't neglect this step since the glue makes the joint slippery, and the pieces can shift out of position as you're driving the fasteners. Slightly angle the pilot holes so the joint doesn't slide apart when you drive the nails. Drive Nails and Sand Apply glue to both ends of the joint. Get both nails started through the pilots before you drive either one of them completely. Countersink the nails as little as possible. Sand the joint smooth and touch up the paint. Smart Sanding Tips Flat Edge Load abrasive paper into a hard rubber sanding block to level the flat surfaces of scarf-joined moldings. Don't concentrate sanding pressure right at the joint line—feather out the sanding several inches to each side of the seam line. Remove dust with a tack cloth, then apply primer to the raw wood. 5 Types of Sanders for Wood and When to Use Them Curved Edge Smooth curved surfaces with sandpaper wrapped around a rod or cylinder that matches the molding. Some good cylinders include round pencils, dowel rods, and PVC plumbing pipes. Pressure-sensitive abrasive (PSA) sticks to the cylinder, making your work easy. Spraying adhesive on ordinary sandpaper is a good alternative to a PSA. Large-Scale Scarf Joints On some large pieces of trim work, such as crown molding, you can join lengths before installation. Doing this significantly reduces the work you need to perform while standing on a ladder. As a result, you get better joints with less work. Accurate cutting of the opposing miters for the joint is still an absolute necessity. Follow the recommended setting time, and before proceeding to the installation, be sure that the assembled joint has developed strength in the glue joint. For the wood gusset, cut the scarf joint, apply glue to the cut ends, and press them together firmly. Align the assembly against a straightedge and apply strips of masking tape to keep the joint shut. Glue and screw a plywood gusset over the seam. As the size of the molding increases, choose thicker plywood, but make sure it doesn't interfere with the installation clearances. Steel mending plates are a good alternative to plywood, lending excellent strength with minimum bulk. Choose coarse-threaded screws for maximum holding power in softwoods. Don't attempt to drive or shoot nails through the metal plates during installation. Disguising the Joint You can do several other things to disguise the joint. If you're joining wood that will get a clear finish, join pieces that have the same subdued grain pattern. Joining a wildly grained strip with one that has straight grain will make the difference immediately apparent. Painted scarf joints are easy to conceal, but they still require careful workmanship and sanding. Paint is merely a finishing coat, not a cure for a poor fit. If you apply stain and a clear finish before cutting the scarf, you won't have to sand the joint smoothly. Although this will save the effort of applying the finish after installation, it means that you'll need to spend extra time to fit the joint as closely as possible. Touch up the joint's ends with a stain pen to eliminate the appearance of raw wood. How to Paint Trim to Give Your Walls a Tidy Finishing Touch More Tips for Installing Trim and Molding It's all in the details. Whether you're on a budget or want to invest in top-tier, custom products, check out some of our DIY ideas to redefine your spaces and make the best of crown molding, baseboards, wall joints, and more. How to Install Baseboard Molding How to Transform a Room with Crown Molding How to Install Plastic Crown Molding as a Budget-Friendly Upgrade How to Finish Drywall Butt Joints How to Install Wall Frame Molding