Square and Layout
Laying out the perimeter of your pole barn.
When squaring our pole barn we usually identify some sort of existing structure to measure from like a fence or a driveway.
We'll use the picture to the right to describe the layout process. You have a 36x24 pole barn you are building but it needs to be 20' from a fence to conform to building codes.
Side A: Measure out 20' from your fence, drive batter board to either side of the mark. Measure again and place a screw in the batter board at your 20' mark.
Next measure 20' from the fence at the other end of the pole barn and drive a stake for a marker.
Measure from your batter board on your first measurement down 40' across the width. Drive batter board 20' from the fence at your 40' length. Make a mark for your 20' distance from the fence and place a screw. Stretch a string across the two nails very taught. You now have your "set line". This will be the side of the pole barn we do not move. All measurements will be made by this string.
About 2 feet from your batter board you will make a noticeable mark mark on the string. From the mark you will measure down the string to 35'9". Tip: Having one person hold the tape by the mark firmly (not grabbing the string). This is a 36' distance and the tape will sag giving you a false measurement. Pull on the tape hard to remove as much slack as you can. Measure multiple times and communicate with your helper before you place your true 35'9" mark.
Side B: Just as we measured from the fence 20', we will measure from your string across the length 23'9" and drive our batter board. Measure again the 23'9" at the other end of your pole barn, drive and mark your batter boards, place a screw and set up a string. Once your string is up, double check your measurements at both ends and adjust as needed to achieve 23'9" length.
You should now have two parallel strings at 23'9" from one another. This must be exact. Your width was set to 40' to allow a few feet on either side of your barn to set your next lines with ease.
Side C: Using the string, stretch it across your batter board and through the marks on your first string line.. Use the speed square and adjust the string until it is through the mark and as square as you can make it. When the string is where you like it, mark the batter board under the string and place screws. Tie your string off and check the square again, you might have to make adjustments. Remember do not adjust your first line.
Side D: From our 35'9" mark on Side A's string we will follow the process for side C for placement. Stretch a string through the mark, square it by moving the string back and forth, mark it, nail it and string it up.
Check your measurement of line B in between the intersections of line C and D. Side B should be 35'9" like side A.
Cross hatch: Basically we are going to check the measurement from corner to corner on the diagonal, record or measurement, then check the other diagonal. The measurement should be the same for the pole barn to be square. If you took your time making the string follow the speed square you should be ready to build. If the lengths are different, you will have to adjust sides C and D until they are the same. Do not adjust side A. After any adjusting check your sides to see they are still at 23'9" and 35'9".
Another way to find the true diagonal length is to use the Pythagorean theorem. (A*A)+(B*B)=(C*C). Length squared + width squared = diagonal squared. Width = 35'9" = 429" while Length = 23'9" = 297" So (429*429)+(297*297)=(C*C) Then, (184041)+(88209)=272250 the square root of 272250" is close enough to 521.75" or 43' 5 3/4". If your diagonals are close to that mark, start marking your post layout.
Marking Perimeter Post Positions
Marking perimeter post positions is as simple as the picture to the right. You can increase the length of your pole barn by 12' sections easily. Just remember to have your beginning and ending sections 11'10 1/2". All sections in between should be marked in 12' sections.
We make a 1 1/2" setback to account for the protruding headers when we install them. Adding the space for your headers and you have a 36'x24' pole barn.