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How to Measure an Inground Pool Liner

Published by Matt Fichera on 04/14/2022

How to Measure an Inground Pool Liner

As liners become old, faded, and stained they are going to need to be replaced. In this article and accompanying video, we're going to show you how to measure a replacement liner step by step. To begin the process, get the following items and tools that you will need:

  • Measuring Tape – We use a 1” wide steel tape measure in this video.
  • Measuring Tool – We will demonstrate one you can make at home.
  • Order Form
  • Clipboard
  • Chalk
  • Pen

Step 1: Measuring the length and the width of the pool.

Take your tape measure and measure the entire length of the pool directly to the liner and not the white coping. As you can see in our video it's 40 feet in this pool. Then take the tape measure and measure the width of the pool in the same way directly to the liner. In this example it's 20 feet. Then copy these numbers to the order form as you can see highlighted in yellow on our video as 20 feet and 40 feet.

Step 2: Measuring the corners.

Pools will either have square, diagonal, or radius corners. In our example we have radius corners. The technique here is to measure from the last piece of straight wall under the clip on both sides making a right angle. In our measurements, you can see it's 24 inches or 2 foot radius for this pool. Then you'll take this figure and put it in the radius section highlighted in the video in yellow.

Step 3: Measuring the depth at the shallow end.

Take your tape measure and measure up to the extrusion which is where the liner is inserted. Please be sure not to measure up to the white coping. In this example we have 40 inches. This measurement may differ at different places around your pool. If this should happen take the lesser of these amounts to give the liner a chance to stretch. Take this data and put it onto the order form which is marked and highlighted in the video in yellow.

Step 4: Measuring how long the shallow end of the pool is.

Extend your tape measure all the way to the break point which is where the shallow end slopes off to the deep end. Then read the measurement from your tape measure. In this example it's 13 feet 4 inches. Then take this figure and transfer it to the order form which is highlighted in yellow in the video.

Step 5: Measuring the slope of the deep end.

As you can see in this cross section of the deep end, we'll be measuring the slope distance which is illustrated in red in our video. Usually both the right and left sides are exactly the same as well as the back bay which is the slope at the end of the deep end. However, in some cases it can be different so you may need to measure that also. We're using a custom-made measuring tool for this measurement. This tool is made with two aluminum poles that are 96 inches long. One pole has a 96-inch folding ruler attached to it. Both poles are attached so that they rotate freely around each other. You can also use two 2 by 2-inch pieces of wood 96 inches long. One person will place this on the deep end while another holds a measuring tape on the top of the pole and measures the distance. In this case it's 48 inches in the video. Take this figure and transfer it to the illustrated yellow box area in the order form that’s highlighted in the video.

Step 6a: Measuring the hopper flat area width of the deep end.

In the cross section we are taking the 20 feet that we got in step one for the width of the pool and then from the previous step we just did, four feet on either side. For the slope distance it’s 20 - 8 which equals 12 feet. Now we know the hopper width is 12 feet which can now be transferred to the illustrated yellow box in the order form on the video.

Step 6b: Measuring the hopper flat area length of deep end.

Take the beginning of the measuring tape and place it on the crease going up the slope to the shallow end. The measuring side is placed at the crease where the slope is going up to the deck and this distance is 84 inches or seven feet in our video example. This can then be placed in the appropriate box which is illustrated in yellow in our video at “H”. Then we can easily obtain “J” with the previous measurements in the earlier steps you take the following numbers and add them up:

4 feet from the slope distance + 7 feet with the hopper length.

Then there's the shallow end we measured at 13 feet 4 inches. We subtract these numbers from 40 and we get 15 feet 8 inches.

Step 7: Measuring the depth of the deep end.

Once again, we can use our specially made measuring device to measure the depth of the deep end. It's important to have one end of the device as far to the center of the deep end as possible. In this example, the measurement up to the water line is 94 inches, however, we also need to measure up to the extrusion which can be done at the side wall. In this example it's four inches from the water line to the extrusion we also need to allow for two inches for the liner to stretch especially on warm day installations. In the illustration in our video, you can see we subtracted the 2 inches from the 4 inches to come up with 96 inches or an 8-foot depth. You then take this figure and copy it to the correct box illustrated in yellow on our video. There you have it. Measuring a swimming pool liner.