Gunite, Fiberglass or Vinyl Liner: Choosing a Pool Type in Louisiana

Written by Big Easy Pool Designs

Three Ways to Build a Hole That Holds Water

Quick Answer: Gunite is sprayed concrete over steel reinforcement, formed to whatever shape you draw. Fiberglass is a one-piece shell manufactured off site and set into the excavation. Vinyl liner is a supported wall structure with a flexible liner holding the water. All three are used in South Louisiana. The right one depends on your budget, the shape you want, how much site access you have, and how long you plan to own the house.

Gunite

Steel is tied to the design, gunite is pneumatically applied to form the shell, it cures, and an interior finish goes on.

Strengths. Complete design freedom, since there is no mold. Any shape, any depth profile, tanning ledges, benches, vanishing edges, integrated spas, and unusual footprints that fit odd lots. It is also the most durable structure of the three and the most straightforward to modify later. For a custom result it is the only real answer, which is why our custom pool design work is gunite based, and why forms like an infinity pool or an architectural pool are possible at all.

Tradeoffs. Highest up-front cost and the longest build, because it is constructed in stages on site with cure time between them. The interior finish is a wear surface that needs resurfacing periodically, covered in pool remodeling and resurfacing.

On our ground. The mass of a gunite shell works in its favor against groundwater uplift, though a hydrostatic relief valve is still standard. See building on a high water table.

Fiberglass

A shell is manufactured in a factory mold, trucked in, and lowered into a prepared excavation.

Strengths. Fast, since the shell arrives finished. The gel coat surface is smooth and non-porous, which many owners find easier to maintain and less demanding on chemicals. No liner to replace and no resurfacing on the same cycle as plaster.

Tradeoffs. You choose from the manufacturer’s models, so shape and size are limited by what exists and by what can be shipped on a road. That last point matters more than people expect. Delivery needs a truck route and a crane or equipment position with room to swing the shell into place, which on a narrow historic lot in Metairie or an enclosed courtyard property can be the deciding constraint. Repairs to gel coat are specialist work.

On our ground. A lighter shell depends more on correct backfill and on water management, both during construction and afterward. Done properly it performs well. Done carelessly, uplift and shell movement are more of a risk than with gunite.

Vinyl Liner

A supported wall structure is set with a floor beneath it, and a fitted vinyl liner holds the water.

Strengths. The lowest construction cost of the three, which puts a pool within reach for budgets that would otherwise be out. The liner surface is soft underfoot, and shape flexibility is better than fiberglass since walls are assembled on site.

Tradeoffs. The liner is a consumable. It will need replacing on a cycle, and UV exposure and water chemistry both affect how long it lasts, which in our sun is a real consideration. Liners can be punctured. Over a long ownership period the replacement cycle narrows the gap against the other two.

How to Choose

A few honest heuristics:

• Want a specific shape, a ledge, a spa, or an unusual footprint? Gunite. The others will not get you there.
• Tight access, and a standard shape is fine? Fiberglass may be excellent, provided the shell can physically reach the back yard.
• Budget is the binding constraint? Vinyl liner, with the replacement cycle understood up front rather than discovered later.
• Planning to own the house a long time? Run lifetime cost, not just construction cost. See what an inground pool costs in the New Orleans metro.

Our post on what type of pool material is best covers the surface and finish side, and choosing the right pool for your needs and budget helps match scope to use.

What Matters More Than the Material

On this soil, in this groundwater, installation quality outweighs the material debate. Backfill placed and compacted correctly, a relief valve where appropriate, plumbing pressure tested before burial, correct bonding, and a deck built on a base that will not settle. A well-built pool of any of the three types outperforms a badly built pool of the “best” type.

Ask any builder how they handle groundwater during excavation and what their backfill spec is. The answer tells you more than the brochure.

Frequently Asked Questions

Which lasts longest?

A properly built gunite shell has the longest structural life, with the interior finish renewed periodically. Fiberglass shells are long lived with their own considerations. Vinyl carries a defined liner cycle.

Which is cheapest to maintain?

Owners often report fiberglass as the easiest week to week because of the smooth non-porous surface. Total cost depends on the resurfacing or liner cycle as much as on weekly care.

Can a fiberglass shell fit my lot?

Only if it can be delivered and placed. That is a site access question we answer on the visit.

Can vinyl work on a high water table?

It can, with proper attention to water management and backfill. Discuss groundwater specifically before choosing.

Can I convert a vinyl pool to gunite later?

Conversions are possible in some cases and are a significant project. See pool renovation.

Talk It Through On Site

We will look at access, ground conditions, and what you actually want the pool to do, then tell you which construction type fits and why.

Big Easy Pool Designs serves Mandeville, Baton Rouge, and the wider metro. See pool types or call (504) 688-4066.