How to Lay Out a Building with Batter Boards
Using batter boards and string lines to establish precise building corners and excavation limits before any digging begins.
Step-by-Step
- 1
Establish the first building corner
Working from the property survey and site plan, locate the first building corner using measurements from the property lines. Mark it with a stake. This is your primary reference point — verify it meets setback requirements before proceeding.
- 2
Establish a baseline
From the first corner, measure along one wall line to the second corner. Use a tape measure along the property line or a known reference to maintain direction. Mark the second corner with a stake.
- 3
Square the layout (3-4-5 method)
From corner 1, measure 3 feet along one wall and mark it. From corner 1, measure 4 feet along the perpendicular wall and mark it. The diagonal between the 3-foot and 4-foot marks must be exactly 5 feet for a perfect 90-degree corner. For a larger check, use multiples: 6-8-10 or 9-12-15.
- 4
Locate all four corners
Measure from the established baseline to locate all four corners. Verify by measuring the diagonals — both diagonals must be equal for the building to be square. Adjust until the diagonals match within 1/4 inch.
- 5
Set batter boards
Set batter boards 3–4 feet outside each corner — far enough that they survive excavation. Drive two stakes and nail a horizontal crosspiece at a consistent height. All batter boards should be at the same elevation if possible.
- 6
Transfer string lines to batter boards
Stretch string lines between batter boards to represent the building lines. Use a plumb bob to align the string directly over the corner stake. Saw a notch in the batter board crosspiece at that exact point so the string can be replaced precisely if disturbed.
- 7
Verify final layout
With all four string lines in place, re-measure all dimensions and both diagonals. Check that string intersections fall directly over the corner stakes with a plumb bob. Anything over 1/4-inch error should be corrected now — it only gets worse downstream.
- 8
Mark excavation limits
Transfer excavation limits to the ground with marking paint. The footing is wider than the foundation wall — include that overhang plus working room (typically 12–18 inches extra on each side) in the excavation limits.
Pro Tips
- → Use bright-colored string for visibility, and mark batter board notches with permanent marker so the string can be repositioned identically after excavation.
- → Take a photo of the full layout with stakes visible before excavation — it's your reference if anything is disturbed.
- → Check diagonal twice — once before excavation and once after rough grading — to confirm the layout survived.
Watch Out
- ! Never skip the diagonal check. A building that's 1 inch out of square creates cascading problems through every trade that follows.
- ! Protect batter boards throughout excavation — once they're gone, you're re-surveying at full cost.