Get a Free Estimate

Gunite or fiberglass for your in-gound swimming pool: Part 2 of 2

Second of two parts

In Part 1 of this two-part series, we looked at ten decisions you'll have to make before installing an in-ground pool. If you have decided to take the plunge, you will now have to decide between the two most popular materials for in-ground swimming pool construction -- gunite and fiberglass.

  1. Gunite is the traditional material for in-ground pools. A mixture of cement and sand, it's combined with water as it's sprayed under high pressure into a form. Unlike regular concrete, it holds its shape and does not sag. In construction, the hole is dug and lined with reinforcing metal rods (rebar), and the gunite sprayed in and smoothed over. Then it's finished with a coat of plaster.
  2. Fiberglass is made of glass fiber that's coated in resin. There are two methods of fiberglass fabrication: chopper-gun and cloth lay-up. The chopper gun method involves spraying a combination of resin and fiberglass shreds onto a form, while the higher-quality cloth lay-up consists of laying sheets of resin-coated fiberglass cloth onto the form. The lay-up method is far stronger. In either case, a hard, smooth gel coat covers the pool's inner surface. Fiberglass swimming pools are manufactured at the plant and trucked to the site.

5 points for comparing gunite and fiberglass pools

 Here are 5 considerations to examine when comparing the two materials:

  1. Shapes: Gunite pools, because they are created in holes excavated at the site, can be any size and shape that fits the available space. Fiberglass pools are limited to the shapes and sizes offered by the manufacturer. The largest fiberglass pools are about 16-feet wide and 40- to 45-feet long.
  2. Expense: Fiberglass pools are both cheaper -- and quicker -- to install.
  3. Aesthetics: Fiberglass pools have smooth surfaces which can be slippery. Some manufacturers are putting a slightly rougher surface on the bottom to provide better traction. Gunite pools have a rough surface that can be abrasive on your feet. Because gunite pools are custom-built, they can be shaped more creatively to the landscape, and also can incorporate more decorative elements such as tiles.
  4. Cleaning and maintenance: The smoother surface makes fiberglass pools easier to clean. However, using the wrong kind of chemicals in the water can eat away at the gel coat and damage the finish. Gunite's rougher surface makes it more difficult to clean. When gunite swimming pools are new, it's sometimes harder to keep the water chemically balanced.
  5. Durability: A well-made fiberglass pool is very durable -- leaks are more likely to happen at fittings and piping than in the pool itself. Gunite pools require much more attention to their surface, needing intense cleaning or acid washing every several years. As a concrete product, cracks in gunite do happen.

Glass or gunite? Fiberglass cloth is cut; gunite is dried. But the choice is not cut and dried.