Squaring a Post Frame Building

In this post I will discuss the first step in building a pole building. I will show the method Wagler Builders LLC uses to mark the foot print of the building. This includes setting up strings along all four sides of the building and squaring the building using the hypotnuse method. If the building isn’t started square there will be all kinds of issues.

When starting a building it is very important to put the building exactly where our customer wants it. Customers often mark the building with stakes at all four comers or telling us to measure off an existing building or fence.

We always start by making 8 nice wooden stakes. These stakes need to be pointed sharply and about 2 feet long. Tools needed for this part of the project are a 12 lb sledge hammer, a nice string line, a hammer and roofing nails, a 100 foot tape, and a marker. The following steps are shown in the drawing below. Each Step contains a number on the drawing. Refer to the drawing to help understand the steps.

Square a BuildingStep 1: Stretch the first string line. We put our two stakes about 2 feet past where the corner of the building will be. Then we stretch the string over the corners of the building and fasten it to the stakes with roofing nails. This line is running along the 60′ side of the building. If you are measuring off an existing building or fence, now is the time to perfect this.

First string line

First string line

 

Step 2: Stretch the second string line along the other 60′ side of the building. Measure exactly 3 inches less than the final width of the building. For the 40 foot wide building the string should be stretched exactly 39 feet 9 inches away. This is done because the string lines will be used to set the poles. All the poles will have 1 1/2″ wide purlins and headers nailed outside of them. This will bring the building to exactly 40 feet wide. After the 2nd string is stretched measure both ends again to make sure it is right.

Measuring for 2nd string line

Measuring for 2nd string line

 

First two string lines

First two string lines

Step 3: Mark the first corner of the building on the string line. Take a magic marker and mark right above the first corner.

Step 4: Mark the second corner of the building. One man hold the end of the 100′ tape measure on the first mark. The other man stretches the tape along the first string line and marks the second corner exactly 59′ 9″ away.

Marking the 2nd corner

Marking the 2nd corner

 

Step 5: Figure out the cross measurement (or hypotenuse) of the building. You may have learned this in geometry class and most smart phones now have calculators that can easily do this. The formula used by Wagler Builders LLC is:

Hyopotnuse formula

So one man holds the end of the tape on the original corner while the other man goes across the building to the opposite corner (5) and marks exactly at 71′ 9 1/4″.

Marking the cross measurement

Marking the cross measurement

 

Step 6: Mark the last corner of the building. A man will then hold the end of the tape on this newly marked corner (5) while the second man will stretch the tape along string line 2. He will measure exactly 59′ 9″ along string line 2 and mark the last corner (6) of the building.

Step 7: Double check 2nd hypotenuse. Now all the corners of the building will be marked. Just to make sure everything is right we then measure the other hypotenuse of the building. This will be from the marker marks at corner 6 to corner 4. If this measurement is exactly 71 feet 9 1/4 inches then everything has been measured correctly.

Step 8 and 9: Stretch the strings along the ends of the building. Stretch a string over the marks on the strings to see where the stakes belong. Pound in the stakes then stretch the strings over the marks again. Put marks on the stakes. Then put nails on the marks and hook the end strings on these nails.

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Now you will have four strings that will be the outside of the posts that will make up your pole building. These strings will be exactly 3 inches less than your final building dimensions. They will also be square.

It is time to mark where the posts will go. Usually they are every 8 feet. When there are doors involved the pole spacings may vary. This drawing shows where all the posts are to be marked on a 24 x 24 building.

Post Placement

One man will hold the tape at the corner. He will hold it 1 1/2 inches past the corner. The other man will stretch the tape along the string and mark where the post holes are to be dug. He will mark this on the ground with orange marking paint. It will be marked several inches inside the string line so it is exactly at the center of the post

Marking for the post hole

Marking for the post hole

Once all the post holes have been marked the strings will be wrapped up and we will dig the holes.

Lets dig some post holes!!

Lets dig some post holes!!