How to Replace Clapboard Strips
Wood siding shrinks in cold weather and expands in the summer. This can cause it to crack and split. You can fix damaged boards or replace them. If you have to replace 3- or 12-inch-wide clapboard, you need a pry bar, a hammer, a small hacksaw, a keyhole saw, blunt-tipped thin-shank siding nails, and as many replacement boards as you need that are similar to what’s on the house. Here’s what to do:
Carefully lift the panels above and below the damaged panel. Place shims under the edges to keep the panels raised.
Notice where the nails securing the damaged piece are located because that’s where you will nail the new panel.
Use a small hacksaw to cut through existing nails.
The hacksaw can make a coarse or finer cut, controlled by reversing the blade. When you’re cutting wood siding, you want a more precise cut so you don’t damage adjacent boards.
Using a keyhole saw, cut the first board into pieces.
Cut the ends so that joints on the replacement board will not be directly above or below another joint. If they line up, the repair will be noticeable and less weather tight. If necessary, you can also cut through the center of a board and take it out in pieces.
Pry up the split pieces.
Work carefully so you don’t damage sound boards. Be sure to get everything out.
If the saw cut into the underlayer, seal the damage with roofing cement.
Measure the space for the replacement panel, deducting 1/2 inch from the actual length of the space.
When the board is in, there has to be a 1/4-inch gap on either side to allow for expansion.
Cut the new panel to fit and seal the trimmed edges with paint or wood sealer.
If you’re putting in several rows of replacement boards, start at the bottom and work your way up.
Fit the replacement board in.
You can drive the replacement in without damaging it by placing a block of wood along the bottom edge and hammering on it instead of the panel.
Secure the panel with nails.
Place the new nails where the old ones were, and be sure the nails are set 1/8 inch below the surface of the board. Don’t hammer nails through any adjacent clapboard or it may crack.
Never put nails directly into the boards below because doing so will impede expansion and contraction that occurs naturally throughout the year. If the boards can’t move, they’ll crack and moisture will get into the wood, causing even more damage.
Caulk over the nails and along the joints between the new and old boards.
Finish the boards with primer and paint or stain matching the rest of the siding.