Pull a Bowed Deck Board Straight With a Clamp and a Speed Square

The Problem

Deck boards arrive with a crown or a bow in them. Laying a bowed board next to a straight run leaves a gap that opens in the middle and closes at the ends, and the bow has to be pushed out while the screws go in.

Doing that alone means one hand levering the board over with a pry bar or a chisel dropped into the joist, and the other hand trying to drive a screw. The board springs back the moment the lever moves to the next joist.

The Technique

A speed square makes the anchor a clamp needs.

1. Drop the fence of a speed square into the gap between two boards that are already fastened down, a board or two back from the one you're laying. The fence hooks the edge and the body of the square lies flat on the deck.
2. Set the bowed board in position.
3. Hook one jaw of a bar clamp against the speed square and the other against the edge of the bowed board.
4. Tighten the clamp. The board pulls into line against the square, which can't move because its fence is trapped in the gap.
5. Drive your screws.
6. Release and move both along to the next section of the bow.