How Fiberglass Pools Are Made: 3 Steps

Have you ever wondered how an inground fiberglass pool is created? Let's break down the 3-step process to making a fiberglass pool from scratch:

1. The production of the pattern or "plug"
2. The production of the mold
3. The production of the pool shell

The pattern

This process begins with the production of the pattern (also called the plug)—the original shape of the pool shell. We construct it using wood, fiberglass, body filler, and primer.

It's not a pool, but it's an exact replica of the pool.

From this, we'll create the mold.

We build the mold inside the pattern, then remove it from the pattern.

Once we finish the pattern, we apply liquid sealers and release agents to the pattern to allow the completed mold to be removed from the pattern.

It takes 3–4 months to build the pattern.

The mold

The mold is the second step in the creation of a new fiberglass pool design.

The mold has an orange-red exterior and is constructed with fiberglass and a steel-framed interior.

Once we remove the mold from the pattern, we flip it over and prepare the surface in a similar manner to the pattern so that the pool shell that will be built upon it can release.

We keep our molds on wheels so we can roll them around.

We make the mold orange for good contrast against the pool's blue gelcoat. This ensures that we get good coverage and that we can easily see if the mold and pool stuck together anywhere.

A steel frame supports the entire underside of the mold.

Producing the pattern and mold is 95% of the work of creating a new fiberglass pool design.

It typically take 3–4 weeks to build the mold.

The pool shell

Creating the pool shell is the third and final step in the process.

After the mold is complete and ready to use, we build the pool on top of it and then release the pool shell from the top of the mold.

It only takes 1–2 days to build the pool shell.

Releasing the pool shell from the mold

We wheel the mold out of the building, connect straps to the pool shell, and then pull the pool shell from the mold.

Pulling the first pool off of a new mold is when the builders get a little nervous. Sometimes things get stuck, despite all the best efforts and best practices and great release agents that are supposed to allow the pool to come off the mold. We celebrate a smooth, even release!

After we remove the pool shell, we can wheel the mold back into the building and build many, many more pools from it.

Want to learn more about the manufacturing process for our fiberglass pools? We'll show you exactly how we build the pool shell, step by step—and why we developed these groundbreaking best practices!

Feel free to take a closer look at our pool models while you're here. You can also try out our fiberglass pool pricing calculator or visit our learning center to learn more about inground pools. 

If you have any questions or comments, please feel free to leave them below.

At River Pools, we manufacture world-class fiberglass swimming pools for installation across North America and have a wide variety of models to choose from.

Get in touch with us, and we’ll be happy to help you on your pool journey!

Thanks and have a great day!

Up Next:

What is a Fiberglass Pool Mold?

The Pros and Cons of Fiberglass Pools

What’s the Best Small Fiberglass Pool for Your Needs? Costs, Sizes, Features

Editor's Note: This article was originally written by Jason Hughes on December 30, 2015.  Any opinions expressed are those of the author. Any prices referenced were based on information that was readily available at the time.

River Pools is a brand of inground fiberglass pools produced in a manufacturing facility in Fortville, IN. While our expertise is in manufacturing fiberglass pools, we have access to a network of installers with expertise relating to project design, installation, and pool service. We often tap into this knowledge base and share information freely with homeowners, just like you, considering installing a swimming pool in your backyard.