and manufacturers are seeking to further blur the lines between
vinyl-liner and concrete installations.
It’s a marked departure from the kit-pool mentality now
that installers offer an endless variety of shapes and intricate
features without affecting the pool’s performance or
But constructing such specialty pools is no cakewalk.
Here, vinyl-liner veterans identify six trouble spots frequently
encountered in the field, as well as tips for working through these
1. Compact and de-water the soil.
As vinyl-liner installations become more customized, builders are
growing increasingly adventurous about grading around the
But if done incorrectly, it can cause the vessel to move,
resulting in leaks and other problems.
In fact, when homeowners ask the staff at Burton Pools and
Spas to check out a troublesome pool built by another company,
leaks are among the most common discoveries.
“Instead of bringing it down to natural grade, properly
building it up or using some kind of retaining system to hold in
the dirt, they’ll try to just pile dirt and then install the
pool,” says Jesse Anderson, construction supervisor at the
Fort Smith, Ark., firm, a Pool & Spa News Top
“Then, two to five years later, you’ve got major
settlement,” he adds. “They’re just asking too
much of [the ground] to support that weight.”
If you do build up the grade, be sure to properly compact the
soil. Consult local codes, which may specify accepted compaction
methods or rates. They also may tell you how large a layer, or
lift, you can put down before compacting it with water or a
Some areas require a 95 percent compaction, which often must be
verified through testing.
If the area has a high water table, you must find a way to
divert the moisture away from the pool. Otherwise, water can build
up behind the liner, causing it to float. Anderson recommends
deciding how to do this when first surveying the site. It’s
always a good idea to make gravity work for you, so figure out how
to move the water downhill.
Locate a low point where the water can flow. Surface drains are
less expensive and require minimal maintenance, whereas drain pipes
must be watched because they tend to clog up.
Regardless of the system you use, just make sure you don’t
direct water toward the house.
2. The liner must fit on custom pools.
On rectangular pools, there’s usually little worry that the
liner will fit perfectly, and measuring is simple.
But free-forms, particularly the custom variety, can get
complicated. When laying out the panels, you have to take many more
measurements to plot various points on the curve.
“If you don’t do it right, you’re probably
going to have problems with the liner fitting correctly — you
will probably have wrinkles,” says Ron Fronheiser, president
Pools in Bally, Pa. “If the pool was supposed to be 14
feet wide at a given point, and it wound up being 13 feet, 8
inches, you would probably have wrinkling going on at that
When measuring for the panels, don’t skip any steps. Take
every measurement called for in the plans, and double-check each
one before pouring the foundation.
If your measurements can’t be absolutely precise, make the
measurements slightly larger. This way, the liner will still fit
tightly. This is especially important on the slope between the
shallow and deep ends. Otherwise, the slopes on the liner and floor
won’t match up.
“If I have a break point on a pool that is supposed to be
15 feet [wide], I try to err on the side of being maybe 15 feet 1
inch, instead of 14 feet 10 inches,” Fronheiser says.
“They actually make the liner a little bit smaller than the
But don’t vary from the plans by more than an inch or two,
he adds, or you risk overstretching the liner.
Burton Pools and Spas uses a different — but no less
effective — method to ensure the panels and liner fit like
gloves: The company’s crews combine the excavation and
“While we’re digging, we’ll be setting our
panels and doing our measuring,” Anderson says. “If
there’s a mistake, you find it a little faster because your
panels are coming together and you see it.
“Then, before we pour our bond beam, we always
double-check our measurements,” he adds.
3. Prevent leaking behind water-features and spas.
Special care must be taken when attaching another wet element, such
as a waterfeature or spillover spa. As water spills into the pool,
it has the potential to wick around and creep behind the
Of course, always apply some kind of waterproofing membrane on
the waterfeature structure itself. Also try at least one of the
- Run a bead of silicone caulk along the joint between the
liner and secondary vessel.
- Place a drip edge on the underside of all weirs and
spillways. To do this, make a saw-cut across the width, a couple of
inches behind the edge of the weir or stone, creating a stopping
“When water gets to that point, it has a tendency to stop
and drop off the edge of the rock instead of holding onto the
bottom,” Anderson says.
Even if the volume is enough to sheer off the weir, cut the drip
edge for those errant drops that wick back.
For additional waterproofing between the pool and waterfeature
or spa footing, place a piece of 1/8-inch rubber liner on top of
the pool-wall panel.
“We bolt that down and really caulk and silicone the whole
joint where the panel and the rubber meet up,” says Tim
Tindall, co-owner of Muskegon, Mich.-based Tindall
Construction Inc. “Then we drape it [over the footing].
After finishing the stone and mortaring it in, we cut out the
Now even water that might otherwise leak through the mortar
joints will seep into the pool instead.
4. Use caution when backfilling radiused panels.
Once the panels are up, builders may struggle to pour foundations
and backfill behind them without tipping the panels over.
“Sometimes if you backfill and don’t have enough
supports inside, you might get a panel that bows in,” Tindall
Until the panels are equalized — with water inside and
soil outside — they should be supported on the inside with
the type of braces used to create concrete forms. (Note that these
are different than the back braces provided by
Rectangular pools are easy. Tindall and his company generally
can finish a job with three to four supports on each side. But
radiused panels are more likely to bow in or tip completely on
When backfilling behind these panels, use extra supports,
including one at the center of the radius. Then backfill more
slowly than you would with straight sides or hard corners.
Don’t add more than a foot of soil at a time.
Compacting gravel helps: Because it self-compacts and
self-levels, it will exert equal pressure as you add it.
5. Remember unique steps for coping.
More vinyl-liner pool builders are adding cantilever coping to
their vessels to prevent them from looking like they came from
kits. On such projects, builders must pay close attention to a
couple of side issues.
First, be sure to match up the cantilever forms with the track.
Both components must come from the same manufacturer or they
won’t fit together properly.
“When you pour your concrete, it may slip out on you, it
might push away, and then when you pull your form off, your
concrete won’t be finished correctly,” Fronheiser says.
“It’ll have a little bump out where it’ll be out
past the wall of the pool. You can definitely see those
Additionally, watch where you place joints on cantilever or
stone coping. If possible, place a coping joint wherever two panels
“Ideally, it should be placed right [over] a panel joint
because that’s where the panels can move a little bit,”
6. Properly support waterfeatures.
Waterfeatures remain a fairly new vista for many vinyl-liner pool
builders. So there’s still a learning curve.
Adding intricate and heavy rock waterfalls, for instance,
requires installers to abandon the kit mentality that usually
follows this type of construction.
One challenge in particular involves supporting the rock
waterfall so that it doesn’t weigh down the wall panels. On
such installations, contact the package-pool manufacturer
“Some of them have braces developed to handle a little
more weight,” Anderson says. “As long as we know what
we’re going to build and how much it’s going to weigh,
a lot of the manufacturers we work with will let us know what we
need to do.”
On especially heavy waterfeatures, some type of foundation is
needed. The manufacturer may recommend pouring concrete piers using
Sonotubes, or a more solid footing.
Some builders have found tried-and-true methods for supporting
waterfeatures. Fronheiser’s company recently built a 10-foot
stone waterfall with a vinyl-liner pool. His crew created a deep
footing by pouring concrete in place of the normal backfill, behind
the panels where the waterfeature would sit.
“We always pour a concrete footer at the base of our
walls,” Fronheiser says. “In this particular case, we
just brought the concrete right up to the top of the pool because
we were handling so much weight. That’s pretty extreme.
Typically, you don’t need to do that much. But we were
putting huge boulders on this wall, and we wanted nothing to be
able to settle there.”
When working in problematic soil, consult a local soils
engineer. These professionals can better anticipate how much
pressure expansive soil, for instance, will exert on the
Measuring free-form pools requires extra care.
Illustration of a drip edge for use on the
underside of weirs and spillways.
Package pools are poised for growth, even in a
Experts share tried-and-true techniques to
ensure a taut vinyl-liner installation.