San Juan Fiberglass Pools

What are Fiberglass Inground pools, how are they manufactured, how does the installation process work, and are they worth the cost? These are a few questions that you probably have if you are thinking about installing a fiberglass pool. One thing you will realize as you research fiberglass pools is that there is quite a few manufactures out there. San Juan, Leisure, Viking, Trilogy, and Sun are a few of the companies that produce fiberglass pools.

The first fiberglass pool I installed was a San Juan model in ’02. We have been a dealer with them ever since then. They have always stood behind their product for us, and we have not had any issues with them.

So what are Fiberglass Pools?

Very simply fiberglass pools are a complete one piece unit. They are manufactured in a controlled factory setting, being built on a preformed mold. They are made using fiberglass material for the shell, with a gelcoat finish on the interior of the pool that is 30-32 millimeters thick. The following paragraphs explain the materials and process that San Juan uses to build their pools.

The type of resin makes a difference.

From the marine industry we have learned that only Epoxy type resins are impervious to water. Vinyl Ester resins are made with many of the same products that go into epoxy. This is why all good boat builders and all good swimming pool builders use a Vinyl Ester resin for the layer of fiberglass next to the surface. Vinyl Ester resins also have better mechanical properties than polyester resins. This is why the very best boat builders continue the use of Vinyl Ester resins throughout the laminate. At San Juan Pools we realize that the back of the pool shell needs to be impervious to water just as the front, and that the better mechanical properties of Vinyl Ester resins make for a stronger shell. When looking at the total cost of a pool project, it does not make sense to use cheap general purpose resins in the manufacturing of your pool shell. San Juan Pools is the only fiberglass pool builder that uses Vinyl Ester resin throughout the laminate.

The type of fiberglass reinforcement makes a difference.

The aerospace and marine industries would never think of using chopped fiberglass for structural components, yet most of the fiberglass swimming pool industry uses chopped fiberglass for the majority of their shell. Anything that is sprayed on a mold with a gun is not structural! Filled resins, ceramic cores and chopped fiberglass make a part thicker (stiffer) but do not add significantly to the strength of the laminate. Which do you believe is stronger, a continuous piece of rope or a rope that has been cut into little pieces and glued together? Woven roving is a fabric made by weaving continuous strands of fiberglass together. San Juan Pools uses at least 48oz per square yard of woven roving everywhere, with many areas of the shell having more than 72 oz per square yard of woven roving.

All of our shells have a minimum of 48 oz per square yard of woven roving everywhere. 

First we apply the surface. Then we skin this with 1.5 oz per square foot of chopped strand mat. Then we lay up the pool in panels with each panel consisting of a 1.5 oz mat, a 24 oz woven roving, a 1.5 oz mat, and another 24 oz woven roving. Deep pools get an additional layer of mat and woven roving.

We have two types of surface finishes:

Our White and Sulli Blue pools use an NPG/ISO (Neopentyl Glycol Isophathalic) based Gelcoat. This is specially formulated for the pool industry, it is UV stabilized and corrosion resistant. The strength of this finish is well proven with many pools having this finish that are well over 25 years old. As crystal clear water will always have a sparkling blue look many pool owners see this as the most beautiful of all finishes.

We also have our new Iridium colored finishes. This is a solid surface material consisting of oven cured colored chips in a clear UV and chemical resistant clear resin. This surface finish is backed up by a color matched gelcoat that acts as a barrier coat as well as a primer for the fiberglass. Click here to see designer colors.

how are fiberglass pools installed at your house?

The installation process is fairly simple. This is where having your pool built in a controlled environment comes into play. The typical fiberglass pool can be set, backfilled, and full of water, ready for the decking around the pool to be placed in 2 to 3 days. This is the advantage of fiberglass over concrete or vinyl liner inground pools.

Once the excavation of the hole is done, the base for the pool to set on is placed. Fiberglass pools have traditionally used sand for this. In the last few years some builders have started using a crushed gravel that is 3/8 of an inch or smaller. We have switched over to using the gravel in our installations. Using sand never really made sense to me because you have to wash it into place with water. At the same time you do not want water building up around the outside of the pool, so you have to pump the excess water out. Once the pool shell is set and level, it is backfilled completely, while water is added to fill the pool at the same time. With using gravel for backfill you get an almost 100 percent compaction rate compared to using sand, without using all the water to wash sand into place. You can read a great article (click here) by friends of ours at River Pools and Spas in Virginia, about the comparison between sand and gravel backfill.

Removing Ground Water!

Having a system in place to remove ground water, is a very important step in fiberglass pool installation. You might have heard the myth, “a fiberglass pool will pop out of the ground”. Very true……for any type of swimming pool. Concrete pools, vinyl liner pools, and fiberglass can all pop out of the ground. There has to be a system in place to deal with the effects of ground water for every type of pool installation. We install sump systems on every inground pool we install, whether a vinyl liner or a fiberglass.

Are Fiberglass Pools worth the cost?

When comparing costs between fiberglass, vinyl liner, and concrete pools, fiberglass will always be near the top of the list cost wise. Concrete and fiberglass will be comparable in price, with vinyl being the least expensive. Fiberglass is considered a permanent pool, along with concrete, while vinyl is not. The big reason that fiberglass pools cost more is that they are manufactured in a controlled environment. Unlike a concrete or vinyl liner pool that is completely built on site, a fiberglass pool comes already assembled. We install both vinyl liner and fiberglass. Whenever a customer wants pricing on both, the vinyl will always be cheaper. When you look at the price, you should take into consideration two things. The initial upfront cost, and the long term cost. Even though a vinyl pool is cheaper upfront, in the long term you will spend as much on a vinyl, as the upfront costs on a fiberglass. Concrete pools have to be acid washed and resurfaced. Vinyl pools will require liner changes. With a fiberglass pool you have none of this. You will spend less money over the long term on fiberglass, than vinyl or concrete. So is a fiberglass worth the cost? That is a choice that you have to make for yourself, and decide whether that the upfront cost is worth it. 

Fiberglass pools have exploded in popularity in recent years. A lot of this is due to the fact that all manufactures now offer color finishes. Ten years ago all you could get was white, or light blue finishes on the gel coat finish. You could put up the argument that they looked cheap. I would have had to agree with you. With the color finishes today, no more.

Here is a quick list of the pros and cons of fiberglass pools.


  • manufactured in a controlled environment
  • quick install time
  • different colored finishes to choose from now
  • minimal maintenance on the pool. With the smooth gel coat finish algae can not adhere to the walls and row
  • higher upfront costs, but the cheapest pool over the long term
  • steps and bench areas built into the pool


  • size limitations. With having to transport on the highway can only be made so big
  • price. Costs more upfront.
  • staining. You have to use some type of metal out product to keep any trace of metals out of the water

Happy fiberglass pool shopping!!

Additional Resources:

Fiberglass Pools

Fiberglass Spas

Designer Colors


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We Offer 4 Different Types of Pools

Above GroundFiberglass PoolUltimate PoolVinyl Liner Pool