• +1 (888) 818 POOL
  • swimmingpoolsteve@gmail.com

How To Measure Pool Liners

How to measure pool liners

Measuring a new vinyl liner for a pool is something that can be done by anyone however experience goes a long way towards getting reliable, wrinkle free installation results. Learn more about how to measure a pool liner on this page or skip to one of the following sections:

Concrete Pool Videos
Plaster Pool Videos
Vinyl Liner Pool Videos
Measuring Pool Liners
Pool Pumps Introduction
Pool Pump Troubleshooting
Variable Speed Pool Pumps
Pool Filter Videos
Salt Water Pool Videos
Swimming Pool Questions & Answers

Measuring Vinyl Liners

Is It Hard To Measure A Pool Liner?
Learn about how hard (or easy) it is to measure a pool for a new vinyl liner. The features and shape of your pool will determine the difficulty associated with measuring for a new liner. While some basic pools with straight walls can be a pretty straight forward process to measure the liner, more advanced pools will have freeform shapes as well as odd angles which must be accounted for. A freeform shaped pool with a deep and (and shallow end) will require extensive measurements to orient the 2-D shape along with the 3-D hopper, break points and slope measurements.

When you measure your own liner what you are risking is too much material which will result in a wrinkle (or wrinkles) in the liner. This is considered undesirable and even unacceptable to some installers. If you have too little material this can cause the liner to stretch too much. This might result in a wrinkle free installation but one that may likely have a shortened service life due to the tension on the liner and coping. Finally you can have just the right amount of vinyl material, but the orientation or shape of the slopes, breakpoint, shallow end or deep end can be off resulting in large and unsightly wrinkles. It is not hard to measure a pool liner, but you could say that it is challenging and the epitome of situations where you want to "measure twice and cut once".


How Do You Measure A Freeform Pool Liner?

Learning how to measure a vinyl liner for a swimming pool is something that takes experience to do consistently well. Rectangle and circular pools are fairly easy to measure due to their inherent shape. Kidney shaped pools, and any other form of "freeform pool liners" must be measured using a plotting system to allow the liner manufacturer create an accurate 3-D model of the pool. The pool liner must fit exactly in place to avoid wrinkles and the plotting process does this by identifying key areas of the pool and including these referenced points in the measurement plot. You will need to denote the shallow end break, the beginning and end of the deep end pad (floor), the length of the long slope, the back slope and the side slopes in the deep end as well as the overall length, width and depth of the pool.

Since liners are custom made for each inground vinyl liner pool it is extremely important to measure your pool properly. Liner manufacturers can potentially alter a liner that has been mismeasured however this is certainly a situation that you want to avoid. Some liner manufacturers offer a liner measurement service that you can pay for if you are not confident that you can measure it properly.


Do You Measure A Liner With The Pool Full Or Empty?

The answer to whether you measure pool liners with the pool full or empty is that it depends on the situation. For most pools you have the option of measuring full versus empty with the consideration being a more accurate liner fit versus leaving the pool empty until the liner can be manufactured. Ideally a vinyl liner pool should never be left empty as the water (and liner) in the pool help to protect the slopes and floors. When you drain a vinyl liner pool to measure the liner you assume some additional risk being that the pool will be empty until the new liner arrives. Professionals use experience and knowledge of local ground conditions and pool installations to determine when a pool should be measured empty and when it would be safer to leave it full.

Sand bottom pools are the most problematic for measuring new liners with the pool empty. Once you drain a sand bottom pool the floor and slopes will begin to dry out. This can lead to deterioration of the floors and slopes. In the event of torrential rains or flooding, a sand bottom pool risks having the slopes wash out completely which essentially would require a new pool installation to repair. The minimum safe water level in a vinyl pool to protect the floors and slopes is between six inches to one foot of water covering the shallow end floor.


How To Measure The Shallow End

Measuring the shallow end for a vinyl liner is the same as measuring pools that are constant depth, like above ground vinyl liner pools for example. When you measure the liner you will need to take multiple measurements around the entire perimeter of the shallow end walls. You will probably notice some variation is the height that you measure from the floor to the coping track. It is important to mark your shallow end wall height measurement to the shortest wall height. This way the liner will fit the shortest area, and stretch to fill areas that are incrementally larger. Most importantly it avoids having too much material in any one place which would result in a permanent wrinkle in the liner.

It can be confusing to a pool owner measuring a liner for the first time since you do not appreciate how the liner will stretch into place. How much stretch is too much? There is no definitive answer to this, but I can tell you that when measuring a shallow end you must go with the shortest wall height. If the shallow end is an inch or more deeper in another spot due to variations in the floor, this will be compensated for with stretch from the liner and would be considered fairly normal as far as pools go. In theory pool floors should be within 1/4" tolerance, but realistically as a hand built product and with builders of differing skills, you will commonly find shallow ends much worse than 1/4" out.


How To Measure The Deep End

Whether full or empty measuring the deep end of the pool for a new liner can be challenging. Measuring full is probably easier since you can use the water level in the pool to assist you with transferring the level. Using a soft tape measure and weighting down the zero end is one common way to measure the overall depth of the deep end. Simply drape the weighted tape measurer over a pool pole suspended over the center of the deep end. Lower the tape until it makes contact with the bottom. You should be just able to read the tape measurer at the point it exits the water. You then measure from the water level up to the coping height and add these two measurements together to learn the overall depth. Be certain you measure to the pool coping where the liner attaches and not to the pool deck as otherwise your liner could end up too big for your pool. That would result in extensive wrinkles throughout the pool and you would need to have a new liner made (or your existing one altered).

Measuring the deep end when the pool is drained is probably the only measurement that is harder to get when the pool is empty versus when it is full. It can be hard to get an accurate measurement from the deep end pad to the coping height due to the slopes preventing you from using a standard steel tape measurer. It is not common practice to calculate overall depth using the Pythagorean theorem. You would attempt to transfer deck height over the center of the deep end with a pool pole and measure from the floor to the pole, being sure to subtract the distance from the deck to the coping track to get the accurate liner depth. It is common practice to deduct anywhere from 1/2" to 3" in overall depth from a liner deep end to ensure a wrinkle free fit without excessive stretch forces. This is one area where an experienced liner installer will be better equipped to decide how much alteration to overall depth they should take liberty with.


When Is The Best Time To Get A New Liner?

Pool owners often wonder when the best time to get a new pool liner is - in the fall or in the spring? When all other factors are even I would prefer to have a new vinyl liner installed in the spring. This would mean that right after the liner is installed I can fill up the pool and go swimming. This will give you the opportunity to find potential flaws or defects in the liner, or liner installation. I would prefer to find these potential problems right away versus six months later when the pool gets opened for the spring. This assumes however that the existing liner is still in decent shape and not actively leaking.


Spring and fall liner installations relate to seasonal climates mostly, but something that related to all vinyl pools about when the best time to get a new liner is the condition of the current liner. It is not advisable to operate a leaking pool for extended periods of time, nor is it advisable to drain a vinyl pool and leave it for the winter (even if you are planning a new liner installation in the spring) so the correct time to get a new liner is when the pool needs a new liner. It is incredibly common for pool owners to attempt to get "one more year" from failed and failing liners. If the liner has failed and not able to hold water then the right time to get a new liner is now. Immediately. Do not attempt to wait until spring for a new liner if your current one is ripped or leaking.


For a more complete tutorial on measuring pool liners you can read this article about How to install a pool liner


Concrete Pool Videos
Plaster Pool Videos
Vinyl Liner Pool Videos
Measuring Pool Liners
Pool Pumps Introduction
Pool Pump Troubleshooting
Variable Speed Pool Pumps
Pool Filter Videos
Salt Water Pool Videos
Swimming Pool Questions & Answers