How to Square a Corner Using the 3-4-5 Method | Western Interlock
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How to Square a Corner Using the 3-4-5 Method

Today we’re going to show you how to square a corner using the 3-4-5 method (also known as the Pythagorean Theorem). Knowing how to square a corner using this method is useful in many construction applications, but specifically for laying paving stones. 

If you’re reading this article, you’re likely laying a square paver patio, driveway, or sidewalk—and you want your corners to be just right. Below, we’ve provided an overview illustration followed by step-by-step instructions. Follow our instructions and you’ll have a perfectly square corner, every time.

3 Steps for a Perfectly Square Corner

As you can see in the illustration below, it’s fairly easy to. The entire process can be broken into three simple steps.

  1. Establish a Straight Line
  2. Establish a Perpendicular Line
  3. Measure & Mark Your Lines

1. Establish a Straight Line

First, establish a straight line parallel to your project. Take a hammer and pound two stakes in the ground past the ends of one side. Be sure to pound your second stake 12 inches past the edge of your project to leave room for Step 2.

Then, tie a string between your stakes (learn how to properly tie a string to a stake in DIY with WI our tutorial How to Tie a String to a Stake).

2. Establish a Perpendicular Line

Now you need to establish the perpendicular line. Line up a stake parallel to a perpendicular side of your project, 12 inches behind your other stake, as you see below. Tie off your string.

Cross these lines to make a point of intersection. That point of intersection is going to be your corner—and that’s what’s going to be perfectly square.

Now, run your perpendicular line. Take a minute to make it as square as your eye can see so you don’t have to make as many adjustments later. 

After you pounded your stakes in and you’ve tied your string lines, you should have a semi-square corner and string lines running along two sides of your project. 

Next, you’ll need to measure and mark your string lines according to principles of the 3-4-5 Method.

3. Measure & Mark Your Lines

To get a perfectly square corner, you want to aim for a measurement ratio of 3:4:5. In other words, you want a three-foot length on your straight line, a four-foot length on your perpendicular line, and a five-foot length across.

 If all three measurements are correct, you’ll have a perfectly square corner. 

Take it in bite-sized steps. First, measure three feet on your straight line. Start in the corner and measure out. Once you’ve got three feet, make a mark. Second, measure four feet on your perpendicular line, starting from the corner. 

Third, stretch your tape measure from one mark to another. It should equal five feet. If not, measure out your triangle again.

That’s all it takes! Using this simple three-step process is hands down, the easiest way to make a square corner for your paver project.

Learn how to do every step yourself

Here at Western Interlock, we’re on a mission to take the hard out of hardscaping. That’s why we publish DIY tips, tricks, and step-by-step tutorials at and host a live DIY seminar every month during the summer at one of our manufacturing or distribution facilities.

If you have any questions, you can visit our Paving Stone Display at our Manufacturing Facility in Rickreall, OR. Or, give our team of hardscape experts a call at 503-623-9084.

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