How and When to Replace Your Inground Pool Liner

Inground pool liners only last for so long. Then, it needs replacing. If you own a pool, you probably spend most of your time balancing the chemicals and cleaning debris from the water. Yet little by little, the pool liner develops tiny tears and stains.

Those little tears and stains begin to wear away at the integrity of your pool liner. Patches can only help for a short time; eventually, you will need a new pool liner. Here is everything you need to know about when and how to replace the liner on your vinyl liner swimming pool.

Signs That You Need to Replace Your Inground Pool Liner

Pool liners do last for a long time – some last up to 20 years, but most need replacing after ten years. When you need a new one, you will know. There are several signs that you need to replace your liner. Pool liners become brittle, tear away from coping strips, and develop stains and leaks.

Damage from Ultraviolet Rays

We often place pools in the sunniest spots of yards which means they get a lot of ultraviolet rays. The sun can damage the pool liner above the waterline, and it can bleach the liner below the waterline.

Nails and Claws

Fingernails, toenails, and pet claws can create little tears in the liner. Those minor tears add up over time which prompts the need for a new liner. Dogs and their nails are regular culprits for jagged tears in pool liners, especially when they try to get out of the pool.

Hot and Cold

If you live in a part of the world with four distinct seasons, your pool liner will expand and contract as the temperature cools down and heats up. The expansions and contractions can begin to pull the liner out of the coping strips. If your pool liner starts to sag and bubble, then it needs to be replaced.

Yard Shrapnel

If you have trees in your yard or you use a lawnmower, there is a good chance that sharp objects could end up in your pool and tear your liner. During storms, tree branches, yard furniture, and other items we keep outside can land in the pool. Lawnmowers can also send objects into the pool.

Chemical Damage

The chemicals we put into our pools keep the water safe and clean, but those same chemicals wreak havoc on the liners. Chlorine does the most damage. Consider what chlorine does to clothing, and know that it does the same to vinyl pool liners, too.

How to Choose a Replacement Pool Liner

There aren’t many options for replacement pool liners, but you should still have some information before you invest. After all, the cost of replacing your pool liner can be significant. Consider the weather, warranty, and type of pool you have before you make your final choice. For more, you can read our full guide on how to choose a pool liner.

Only Use Virgin Vinyl

Pool liners are made of vinyl. You want one made of virgin vinyl without any used, composite, or mixed products. Virgin vinyl is strong and will expand and contract for a longer time before weakening, especially when compared to other types of recycled or mixed vinyl. New vinyl will stand up to the chemicals and the UV rays that bombard it each day.

Choose Your Mil or Gauge

The thickness of your vinyl liner is measured in mil. A mil is 1/1000 of an inch, and a dime is 49 mil, which is 49/1000 of an inch. Most pool liners are 20 to 35 mil. While we might think a thick mil is better than a thin one, the quality of vinyl makes a difference. So, be sure you have virgin vinyl with a strong mil. Some manufacturers use the term gauge and mil interchangeably.

Many pool liners have different mil measurements for the walls and the floor. The walls get more UV exposure, so the mil should be thicker. If your pool mil measurements are 35/30, this means the wall has a 35 mil, and the floor is 30 mil. There will be a seam where the walls and floor meet when the mil measurements are different.

Read the Warranty

Your new pool liner will come with a warranty. Read the details, so you know what is covered. Some might have 20 years of coverage, but not for anything useful. The cost of the warranty should be justifiable based on the value it offers.

Consider Cost

A new inground pool liner may be costly, but it’s true that the better the materials, the higher the cost. Weigh your options carefully and know what to expect on pool liner pricing.

How to Measure for the Liner

Choosing your liner and your warranty is the easy part. The challenging part involves measuring the liner, especially if you have a pool that is not a rectangle or square. If you have a kidney-shaped pool or an unusual shape like a Grecian pool or L-shape, you might want the company that is replacing the liner to measure your pool. Draining your pool is helpful.

Unfortunately, there aren’t any standard pool shapes. The length and width might be somewhat standard, but the depth changes probably aren’t. And, after inground pools are installed, they settle and change slightly. If your liner manufacturer has a template or measurement tips, follow them carefully because the measurements you send are what they will cut.

As you measure the parts of your pool, record them on a drawing that represents your pool. The drawing does not have to be to scale.

If you do measure your liner yourself, you will need a few supplies.

  • The manufacturer’s liner template or paper
  • Pen or pencil
  • Two 100-foot tape measures
  • Two long roles of string
  • Chalk
  • Some helpers
  • Utility knife
  • Telescoping pole

Measure the Length and Width in Two Spots

The process begins with measuring the length and width of the pool in at least two places. When you measure, pick two parallel locations on the short and long sides, so you have accuracy. Do this rectangular, square, and ovals. If you have an odd shape, these steps do not apply.

When you measure the pool length and width, get in the pool and measure from the liner to liner. Do not measure from the concrete or the coping on the outside of the pool. The ends of the tape measure should touch the walls of the pool.

Some people find measuring easier with string. You can get these measurements with a string that you cut to size, then measure with the tape.

Measure Depths at Several Spots

This is where measuring can become complicated. Most inground pools have varying depths and angles that are easier to measure when the pool is drained. If your old pool liner has pulled away from the permanent floor of your pool, you may need to cut into it to get the accurate measurement from top to bottom. Only cut it if you are confident you are replacing it.

You should get at least three depth measurements. Get one in the deep end, one in the shallow, and one in the middle. Measure from the liner track in the coping to the floor of the shallow end. Do the same with the hopper. Also, measure a mid-point on the slope. Using string here is also helpful.

Measure the Length of the Floor

The liner company will need to know the length of the pool floor. From the inside of the pool walls, measure the shallow end from the point where the shallow end begins to the point where the liner attaches to the wall. You might want to enlist a friend to help with the next measurements.

Once you’ve finished measuring the shallow, move to the slop. Measure the slope from top to bottom. Then, measure the deep end where it is flat (the hopper). Finally, measure the deep end slope to the point where the liner attaches to the wall. You can use a length of string or a tape measure for these measurements.

Measure the Hopper Width and Slope

Pools have various slopes that make the floor of the pool challenging to measure. At this stage, you will want two poles that you can measure. First, vertically drop one pole to the point where the side slope meets the hopper. Then, from the side of the pool, extend a horizontal pole to meet the vertical pole.

Where the poles meet is the slope measurement. You will get a measurement on the vertical pole and the horizontal pole. You will need both to get the slope measurement. Then, subtract the sidewall slopes from the full pool width to get the width of the hopper.

Hire a Professional If In Doubt

If you are unable to get accurate measurements, ask the liner company to do the measuring. This way, if there is a problem, the fault is on the company and not you. They will replace the liner if they make a measuring error. If you make an error, you pay replacement costs.

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How to Replace the Liner

The liner you purchase will come with installation instructions. Different types of pools have various necessities. For example, some pool liners need adhesives to hold it in place, while others are “floating” and use the weight of the water to keep the liner in place. If you are worried about proper installation, you can hire professionals to do the job.

You will need to drain your pool before you begin installing a new liner. Since pools have tens of thousands of gallons of water, you should check with your municipality, so you dispose of the pool water the proper way.

As your pool drains, you should gather the necessary tools including:

  • Screwdriver
  • Push broom
  • Gaskets
  • Shop-vac
  • Utility knife
  • Garden hose
  • Special items like wall foam and adhesives if recommended by the liner manufacturer

Step One: Remove the Liner

Remove all of the faceplates, gaskets. Then, begin removing the liner from the coping tracks. You might need to cut the liner as you remove it because it is so bulky. Take all of the items out of the pool.

Step Two: Fix the Foundation and Walls

This could become a lengthy procedure if your pool has cracks or damage that needs repairing. Inspect the walls and foundation before you cover it.

Step Three: Prepare the Walls and Foundation

Manufacturers will have different steps here. Some might require you to install foam strips to stick to the walls and foundation. Follow the instructions here to prepare to accept the liner.

Step Four: Center and Attach the Liner

You will want to do this with bare feet to protect the liner. Center it on the foundation, then spread it up and into the coping tracks. Tuck it into place.

Step Five: Smooth the Liner

Using a shop-vac, suck the air out from under the liner. Remove a small section of the liner from the coping to insert the shop-vac hose. After you’ve removed the air, push the air out of the foundation with a push broom.

Step Six: Attach the Fixtures and Fill It

Once the liner is smooth and centered, you can reattach the facings, gaskets, and the main drain cover. Then, you can fill the pool. After you have a foot or so of water, check the liner and the fixtures to be sure everything is staying in place.

How to Make Your Pool Liner Last Longer

No pool liner lasts forever, but there are steps you can take to preserve it. For example:

  • Balance the pool chemicals properly (and often)
  • Don’t use abrasive cleaning materials or products
  • Keep your pet out of the pool, or at least offer an easy way for them to get out
  • Install a cover to protect the pool when it’s not in use
  • Tend to small punctures as soon as possible

Final Thoughts

Inground swimming pools require significant maintenance. Fortunately, big projects like replacing the liner only need to be done once every 10 to 20 years. Take your time to measure and install the liner properly so the replacement lasts as long as possible.

Questions? Let me know, I’d be happy to help.

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