Building a Shed - Making Sure It's Square

Drive a stake into the ground to mark the first corner of your shed. In hard ground, you may need to use a hammer to sink the stake far enough to be stable. These stakes will be your reference points while building the shed's foundation or footing.

Drive a stake into the ground to mark the second corner of your shed. This should be the longer side. Using an 8-foot by 12-foot shed as an example, place the second stake 12 feet from the first.

Calculate the distance between the second and third stakes using the formula: A squared + B squared = C squared. In this example, the distance between the first and second stakes is 12 feet. This distance between the first and third stake, marking the short side of the building, is eight feet. Accurately determining the length of the angle between the second and third stakes is the key to making your building square. In this case, side A of your building is 8 feet so 8 x 8 = 64. Side B of your building is 12 feet so 12 x 12 = 144. Adding these two numbers together gives you 208. This is the square of the number you are looking for. To find the actual length of the C side of the triangle, enter 208 into your calculator and use the square root function. The square root of 208 is 14.422 feet or 14 feet, 5 inches.

Drive the third stake into the ground eight feet from the first stake and 14 feet, 5 inches from the second. The short and long sides of your shed are now at a 90-degree angle. Use the same measurement to determine the distance between the fourth stake and the second.

Drive the fourth stake into the ground 12 feet from the first stake, eight feet from the third stake and 14 feet, 5 inches from the second stake.