Laying out your hoop building and getting it square and to the correct dimensions is key to building a hoop barn successfully. It is easier than you think if you prepare in advance using one (we use both) of the methods shown below.
The first method is known as the “3:4:5 Triangle Method” and the second is called the “Diagonal Method.” Both are equally accurate as they use simple geometry in order to achieve squareness which is key to building a hoop barn that will look good and last.
No matter which layout method you use, you will need the same materials to accomplish the layout. The materials consist of 2 x 4s x 4′ long with an acute angle cut on one end to use as stakes and about any boards for making your batter boards. You will need a roll of string and some nails for nailing your batter boards to the stakes after you have driven them into the ground. You will also need a 100′ tape measure for most hoop building sizes to make your layout work easier.
The idea is to place your stakes and batter boards a few feet back from where you intend the outer corners of your hoop barn, like the diagram below. We put them about 2′ – 3′ back from the corners of the hoop building. Then, we can temporarily remove our strings so that a backhoe can get in to dig trenches for wall type foundation or to auger post holes.
The 3:4:5 Triangle Method
The “3:4:5 Triangle Method” of layout for a hoop building produces a perfect 90º corner as shown in the diagram. Square corners force your layout to be a rectangle instead of a parallelogram. The basic approach is to roughly layout your string lines to the overall dimensions needed for the size hoop barn you are building. Then square-up one corner with a tape measure using the 3:4:5 rule. The 3:4:5 rule says if you measure 3′ from the corner one way and mark the string then measure 4′ the other way and mark the string, the diagonal distance between the marks will be exactly 5′ if the corner is square.
After squaring the first corner, then move to any adjoining corner to the first corner, and proceed the same way. After squaring two corners, then check your overall dimensions to make sure you have the size you require. If you do, then all four corners are perfect 90º angles. If not, keep adjusting and squaring two adjoining corners until you have it as close to exact as possible.
The Diagonal Method
The “Diagonal Method” of layout for a hoop building shown in the diagram below works the same way except that you only measure the opposing diagonal corners until you get them the same distance apart. Once the diagonal lines are the same measurement, you will have a perfect rectangle. Use the same methods as described above until you have two diagonal dimension readings that are equal and your overall measurements are correct.
If you are putting your building on posts, you can now move along the strings and mark your post hole locations, either with stakes or maker paint. If you’re excavating for a concrete wall, you’re all laid out and ready to go!