When you’re building a deck or pouring a patio, how do you keep everything square and true during the necessary trenching? With the help of batterboards.

These temporary guides are typically cobbled together on site from five wood scraps: three stakes driven into the ground in the form of a right angle and two horizontal lengths join the stakes.

Batterboards are placed just beyond the corners of the proposed building site (so they don’t get in the way). Strings are tightly stretched between batterboard pairs and fastened to partially driven nails or notches cut into the horizontal members. The strings, which indicate the proper alignment of foundations or walls, are easy to adjust back and forth until everything lines up perfectly.

Batterboards are so named because they were originally used to check the batter, or receding upward incline, of a masonry wall.