Lap Siding Corner Repair

Metal Caps

• Many retro home builders used metal caps that fit over the ends of lap siding at the corners. This type of cap looks nice. It makes the corners appear clean and even, with crisp edges on each piece. Unfortunately, water can get behind the cap causing the ends of the siding to swell. The corners of the lap siding remain intact because the cap keeps the wood fibers together, but it can cause the cap to pull away from the corner. Other problems occur if the cap catches and pulls loose when people brush by it. During the original installation, you can purchase enough to replace bad ones. Otherwise, replace all of them on one side. Pry them up with a screwdriver and then pull the nails with a claw hammer. If the end is swelled, use a hand block to sand it flush. Apply exterior paint to the ends and sanded area and hammer a new cap in place.

Wood Corners

• Contemporary builders often use full-length strips of weather-resistant wood at the corners, one one each side nailed together. The corners might be mitered or employ the simple butt-joint. The shield provided by the cedar protects individual corners of lap siding, but the wood pieces can become damaged, split, splinter or pull loose. Pry off the full-length pieces using a pry bar to expose the ends of the lap siding and apply exterior paint to the ends. Cut new pieces of cedar or other matching wood on a table saw using either the mitered cut, or the simple butt-joint as needed and nail them into place over the corners. Apply a bead of caulk around the perimeter and paint to match the house.

Plastic Patching

• Plastic or vinyl corners are prone to damage if they are hit by something or improperly installed or if railings or other parts come into contact with the corners. Obvious cracks holes or seams appear and get worse. The corner may only be damaged in a small section, and removing the entire corner is difficult because the corners are one of the first items installed on the house and lips or channels on the caps are tucked inside or under other parts. If you have a broken section, cut horizontal lines through the cap above and below the damage with a hacksaw and remove it. Cut a new piece about 6 inches longer than the damaged section to fit over the removed section. Because the edges, lips or channels won't fit under the existing lap siding, cut the lips off, but leave the 90-degree lips or hooked corners on each side. These two lips fit over the J-channel on each side to lock it in place. Snap the new piece on and caulk the edges.

Resins and Gouges

• Make cosmetic repairs happen using epoxy resin. There's different formulas available. Look for resin that contains some type of elastomer that stays rubbery and flexes with the natural expansion and contractions of the wood. If you've got gouges, loose fibers, flaps or soft wood on lap siding corners or anywhere else, you may not need to do extensive repair. Remove the rot or loose fibers with a wire brush, screwdriver or putty knife. Mix the epoxy as directed by manufacturer's directions and trowel it into the damaged area. Allow it to dry and shape the corner as needed with a file, and then with sandpaper if needed. Paint over it, and you'll never know it was damaged.