If board siding is butted together too tightly during installation, it may warp when it tries to expand with moisture changes. You can try pulling the board in flat and tight by driving a couple of long, galvanized screws through the siding into studs (drill pilot holes to avoid splitting the siding). But chances are good that you’ll need to slightly shorten the warped board. Here’s how.

1) If the boards seem to be jammed together at the ends, pry out the nails from the warped area, and continue pulling nails (or you can cut them with a hacksaw blade), working your way toward the nearest end of the siding board.

2) Pry the end of the board away from the house and put a block behind it. Be careful not to damage any building paper beneath the siding.

3) Shorten the board. Sometimes it’s easiest to do this with a saw; other times a rasp, plane, or perforated rasp work better. Allow about 1/16 inch of clearance to the next board.

4) Replace the board and re-nail it.