Installing an Expandable Pool Liner

image from Doughboy.com

Doughboy® Pools have a long and rich history in America. They are one of the only aboveground pools with a deep end section. They are also the only aboveground pool to use an Expandable pool liner.

Expandable pool liners stretch into shape as you fill the pool, by slowly releasing the vinyl liner as the pool fills with water. Other liners are fully lining the walls and floor before filling begins.

Doughboy® sells their own expandable pool liners, or you can buy replacement expandable liners made by GLI, Swimline or Lomart.

In The Swim expandable pool liners are available in 11 stock sizes, for Doughboy® pools with a 60″ or 72″ deep dished out area, at prices from $159 to $429, depending on size, depth and pattern.

Do you have a Doughboy® Pool?

  • Straight wall sections have a slight curve in the panel.
  • 2-3′ safety ledge is installed around a 5-6′ deep area.
  • Deep area is a rounded bowl, not a hopper bottom.

How to Install an Expandable Pool Liner

Tools: Set of 18-24 rubber tipped clamps, soft push broom, rounded end trowel, good set of screwdrivers, razor knife.

Materials: Expandable pool liner ordered to fit pool inside dimensions and depth, new skimmer and return faceplates and gaskets.

STEP ONE: DRAIN THE POOL, REMOVE THE LINER

Most Doughboy® pools don’t have a main drain, so draining completely will require the use of a pump, either a pool side, or a submersible pump.

Once the pump shuts off or starts sucking air, carefully walk down to the deep end, and with a razor knife, cut the liner around the base of the wall, all around the pool. Two people pull the liner up to drain the last bits of water to the pump. Remove the pump, and remove the liner from the floor of the pool.

Working around the pool, remove sections of the top rail and coping strips to remove the liner as it goes over the wall. Replace the top rail sections, but not the coping strips.

STEP TWO: WALL & FLOOR PREP

Now that you can see the wall, broom it clean of any dust or deposits. If rust is visible, scrape off and paint over, and consider using wall foam. Also decide if you can reuse the wall cove, between the wall and floor, or if you should replace the pool cove.

expandable-pool-liner-installation-1

Next step is to prep the floor with brooms and trowels to smooth out the sand, reshaping areas or adding masonry sand if necessary. Remove any pebbles or wind blown debris, and use tools to lower high spots and fill low spots. Start in the deep end and work your way out of the shallow end, creating sharp transitions on the safety ledge and shallow slope.

STEP THREE: INSTALL THE LINER

Here’s where things get different – up to this point, it’s been the same as any other pool liner job, but for an expandable liner, the next step is very unique.

Unbox the liner in a clean grassy area, unfold it and mark the seam intersections with duct tape. This will be helpful to make sure the liner is not ‘askew’ in relation to the round or oval pool shape.

Refold the liner, accordion-style, or fan-fold it starting at the shallow end. With 4 people, carry the liner and place it on the top of the shallow end top rail. Using clamps and all 4 people, carefully pull the liner over the pool, pulling it over the top rails and gently clamping it to the rail.

After some adjustment to center the liner around the pool, using your duct tape marks as reference – adjust the slack of the pool liner, so that the wall-to-floor seam is 4-6″ from the top of the pool wall, then reclamp the liner to the top rail all around the pool.

STEP FOUR: FILL THE POOL, LET OUT THE LINER

The last step to installing an expandable liner is the one that requires close attention. Begin to fill the pool with water, and allow the liner to become taught and stretch.

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For every 1/10 of water added, release the liner 1/10 of the way. This is done gradually, releasing several clamps, allowing the liner to slip a few inches into the pool, and reclamping the liner to the top rail. If wrinkles appear, reach over the wall and pull the liner towards the wall.Filling from a truck, although costly, will make this step last only 1-2 hours. If filling from a hose, you’ll need to let out the liner a few inches, every few hours until completely full, which can take 24-48 hours.

When the expandable liner has completely stretched into place, there should be just a few inches of liner left on the outside of the walls. Remove the top rail sections, place the coping strips over the liner to secure it to the wall, and trim off excess vinyl material on the outside of the wall.

Last step is to screw on the skimmer and return faceplates (tightly), and cut out the vinyl inside the faceplate, to flood the filter system and plumbing.

~ Congratulations! You’ve just installed your own expandable pool liner. There may be a few wrinkles, that’s considered normal with this type of pool, but if you are patient and allow the liner to stretch, wrinkles will be minimal.

BONUS TIPS:

  • Don’t use an expandable liner on a pool not meant to use one – the walls may collapse inward during filling!
  • If filling from a hose, measure your GPM flow rate by timing the filling of a 5 gallon bucket, so that you can time when to release more liner.

Balance the pool water and begin filtering and sanitizing and you’re ready for the first swim in your newly lined Doughboy® pool!

28 thoughts on “Installing an Expandable Pool Liner

  1. Mary Soracco

    Hi…can you recommend a installer to replace my 18 foot round liner with an 18 foot 72″ expandable liner in the Pittsburgh PA area? Thank you.

  2. gilbert guzman

    i have a 16×32 with 72′ deep end that i will be replacing liner and filling this friday. im pretty clear on procedure except the idea of using sand bags in the shallow end. are these recommended or am i ok with just draping over walls and slowly releasing liner in ?

    • Gilbert, you don’t need any sand bags when you are installing an expandable liner. Sand bags are often used for inground pools, but not Doughboy style pools. At least not with the method I’ve used, which is shown in the video below, from Doughboy on installing an expandable liner.

  3. Matt Kiederlen

    I am contemplating replacing the expandable liner in my 16X32 doughboy with a 6 foot deep bowl on one end. If I am reading everything correctly, once the liner gets down to the level of the “shallow” end, I should sandbag it around the shallow end to hold in place and then continue to incrementally let out more liner on the deep end to accommodate the depth, it doesn’t literally “stretch” into the deep end like a balloon? Is that correct?

    • Hi Matt, it does kind of stretch into the pool floor like a balloon, so you let out just enough as the pool fills, so that the liner will stretch into place, as the pool fills. It’s a bit easier if you have trucked-in water, or at least for the first 5000 gallons, then the rest can be filled by hose. Sand bags are not normally used, or needed, and if used may cause it to stretch improperly. Check out this video on installing a Doughboy pool liner.

  4. Brad Anderson

    We have an 18×34 Doughboy pool and needing to replace liner with the standard expandable pool liner. Only issue is we have a deck that surrounds the whole pool and top of deck does go close to edge of pool. I might have 3″-4″ from rail to top of deck. What is best way to install the new liner? Can I use a shop vac method? I see online that pull it over edge of pool but that would not work for me as limited on space. Looking for recommendations

    • Hi Brad, I’ve done a pool like that before, had a wooden deck around 2/3 of the pool, and we had to crawl beneath the deck and work it – ugh. That’s the only way, you have to be able to pull the liner over the wall, all the way around the pool. You could do it all in one stretch perhaps, so there are limited trips under the deck, but if you have a deep end or dished out area, you need it to stretch into place. although it may be successful with a powerful shop vac, to suction the liner to the walls and floor, and fill the pool while the liner remains under suction.

  5. Hi Paul, you could dig out a deep end in the center of a 12×24, but you would need to dig it to specification, or with proper angles, and then have a liner custom made to fit. You would not use an expandable liner, those are used only on Doughboy pools and other pools designed to use such a liner.

  6. Our agp is 18x38x84 expandable. Will an 18x38x72 expandable work. We are having trouble finding the correct size liner.

    • Hi Kris; That would be too much stress on the walls. You could fill in the pool, a foot shallower – but before you do that, I’d call to speak to one of our liner techs in the custom dept, it may not cost that much more to have it custom made, or special ordered, in the correct, 7′ depth.

  7. Kelly Parks

    We just bought a doughboy 41×21 with a deep end. How do we reinstall the liner when it has a filter drain at the bottom of the deep end?? Any help is greatly appreciated!!

    • Hi Kelly, it’s done the same way as without a drain, but first the drain ring screws are installed, and then the vinyl cover the drain is cut-out and the lid securely installed. Then add a 100 gallons of water or so around the drain and stretch out the liner over the walls, and continue filling, stretching and releasing the liner every 6 inches (or so) of water level that is added.

      • Kelly Parks

        Ok so how are we supposed to drap it over the sides and clamp it like they say to when we have to dig the hole for the main drain and the hoses for the main drain we are at that point in the pool process and I’m not quite sure how to do it? Also right now the liner doesn’t seem to be stretched out all the way like we thought it would because of already being installed will it restretch into place as long as we have it in the right area. Thanks for all your help!

        • Kelly, most original Doughboy pools and others that use expandable liners did not have a main drain in the deep end, so I suppose you would set the main drain and pipe firmly in the base of the very deepest part, setting it in a 4x4x4 reinforced concrete pad would be best to prevent movement. Cover the drain pot cover ring holes with tape to keep dirt out if necessary, but remove the cover, ring and screws. After the deep end has a foot or two of water, and the area around the drain is tight and smooth, wade into the water to install the ring, cut out the liner, and install the drain cover, and continue to fill, letting out the liner as you go.

  8. Hi. I had my pump quit and couldn’t afford a new one for a few months. Well the pool got green and nasty, so I drained it. I have a 16x32x7 expandable liner. The sides ended up straight and not on the ledge. Will it go back into shape?

    • Hi Chrissy, it will likely have some wrinkles when refilled, which is somewhat normal for expandable liners anyway. It could also rip or tear when refilling, if it is a very old or weak liner. Those are the worst case scenarios. Best case is that it will go back perfectly, just like before. Probable case is somewhere between perfect and non-perfect. As it fills, you can pull and push the liner here and there, as needed, to shift the liner where wrinkles are forming. Do this before too much water gets over a wrinkle – more than 3″ of water and wrinkles or folds become hard to move or flatten out. If you end up with wrinkles, no big deal, but do need to be careful not to snag wrinkles on cleaning tools (nets, brushes, vacuum).

  9. Brandy Davis

    Hi! I have an 18ftx4ft above ground round pool. I’m wanting to dig it out to about 7ft. Do I need to buy a expandable liner?

    • Hi Brandy, unless you have a pool that is specifically designed for using an expandable liner, the installation process for an exp. liner puts a lots of stress on walls, which may damage weaker aboveground pools. Expandable liners are also Overlap liners only, won’t fit pools that use beaded liners. However you could order a custom liner to fit a ABG pool with deep area. However again, the design of the floor is important, should be constructed with true radius and careful depth and slope, found with strings/stakes and laser-beam guidance. Then a liner would fit properly your deep end. ON page 64 of this Latham Guide – it shows a typical round pool floor design, with deep area, slope and shallow area, looking left to right.

  10. please help me we have 16by 32 pool and expandable liner we need to replace can we do any thing to make it last though the winter or should we do it this fall please help we are in central Oregon and get snow and ice cold weather

    • Davy Merino

      Hi Janet, if you need to replace it due to holes or tears in the vinyl, you could certainly patch the holes with a vinyl repair kit, and that should get you thru winter. Most doughboy pools should remain full of water during winter, but if it wasn’t there may not be a problem. If it’s a very slow leak, you can add water to the pool every so often.

  11. I can’t tell if there is a deep end to the expandable liner. Is there a shallow and deep end to the liner?

    • Hi, they do not have a deep end, no. When installing, you want to position the liner evenly across the pool, and let the weight of the water do the stretching, but don’t let it pull too much material into the deep end. In other words, keep tight tension around the walls, so the liner stretches into place, and does not pull the slack of the liner inward. Use sand bags in the shallow end, to help keep it in place.

  12. Dale Gandenberger

    How do I remove wrinkles upon filling using an expandable LINER ?

    • Davy Merino

      Hi Dale, it’s awfully hard to set an expandable liner in a doughboy style pool, with a dished out deep end, without getting wrinkles, let me say that right off the bat. The best way is to prevent it with 2 or 3 sharp people scurrying around the pool, pulling and releasing the liner slack at just the right moment, so as the water is covering an area, you pull out the wrinkle and the weight of the water keeps it out. This works best of course when filling from a truck, when filling from a hose, it’s so slow that it makes it much harder. If you can pay your neighbor to also use their water supply, $50 or something, it would help.

      Now if the wrinkles are already set in the liner, but it’s not full yet, you can gently enter the pool and push and pull on the vinyl, but stand on a large rounded board or plastic sheet, so you don’t leave footprints (if sand floor). You can also reach far down into the pool, over the wall, grab a handful of liner, and yank it towards the wall, or use poles and brushes to help guide or hold the liner, while the water fills over a wrinkle area. Small sandbags can also be used to hold the liner in place, while it fills.

      If the wrinkles are there, but the pool is already full, well, there’s not much you can do. You can maybe spread them out a bit with your feet, trying to push toward the wall. I often would use a 4′ long piece of 2″ PVC pipe, with a 2″ Tee fitting on the end, as a ‘wrinkle tamper’. For pools with sand bottoms, you can use such a tool to push out small wrinkles, again towards the wall, or in some cases, slightly dent the sand along a wrinkle, to allow room for the wrinkle to spread out.

  13. Jen Jantz

    We just purchased a 24′ doughboy and when we started filling the pool there was only about 6-8″ when the walls started buckling. We released the liner from the edges but it fell below the edge of the pool forcing us to drain it and now start over. Any idea what we did wrong and how to do it right??

    • Hello Jen, I would guess that the liner was just a little too tight over the walls, and needs to have more slack released, sooner. It takes a lot of baby sitting, if filling with a hose, check on it every hour, releasing another inch or so. Also check that the walls are tight and everything is buckled and buttoned as it should be, on the wall uprights. And of course, read your installation manual closely, and if needed, contact Doughboy, they are US based, in Arkansas (I’ve been there!)

  14. William A. Smith

    We have a 15 year old used 28′ Doughboy above ground steel pool that was recently given to us. Would like to add a main drain kit with a new expandable liner. How do you install drain kit with liner?

    • Davy Merino

      Hi, a main drain is a good idea, but it does increase work and cost. It must be set into a concrete bottom, probably a pad at least 4′ in diameter, built with steel, very sturdy so it doesn’t move or crack. Then a pipe is run under the pool floor, through a trench to a point outside the pool wall, where it runs in a trench to the pump. A 3-way valve is installed in front of the pump to control skimmer and main drain flow. An easier (although less safe) alternative is to install a low water suction, a suction intake line 1.5″, at the bottom of the pool wall.

      To install a main drain, You would use a vinyl liner type of drain that has a sealing ring and screws – when installing the liner, after adding the first 500 gallons, you carefully wade into the water and screw on the vinyl drain ring and cut out the vinyl inside the ring, then screw on the main drain cover.

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