Can I Build My Own Fiberglass Pool?
5/12/14 6:00 PM
by Frank Kearney
I hear this question more as the summer gets closer and people want to get in their new fiberglass pool quickly. Although we do have people call on May 1, wanting to be in their pools by Memorial day, most people understand the time to get started is in January, and even better in November.
But there is one way to get things done at your own pace, and that is to build your own fiberglass pool. I will caution you up front, this is not for someone without any construction experience, or without at least some knowledge of construction techniques, and mistakes can be expensive, but here are a few things that might help.
EXCAVATION – The excavation drawing is provided with the fiberglass pool shell, from San Juan Pools. This will give you a clear and precise outline of how deep your excavation needs to be at certain points, and will exactly match the profile of the swimming pool shell. We own an excavator for our work, and find it superior to a backhoe. Because an excavator can turn 360 degrees we can pile the excavated dirt behind us, whereas with a backhoe it must be piled to one side or another. In some circumstances that can be a problem.
POOL PLACEMENT – If you have a large excavator you can use it to unload the pool. Otherwise you should count on a boom truck, or if things are tight even a large crane. We like to use a construction forklift if we can because they are very maneuverable, and are excellent in tight situations. Be extra careful when lifting the shell off the transport. It is at this point you might cause stress cracking. Use long straps, 20′ if you can, and otherwise use a spreader beam, which San Juan Pools will include with the pool for a fee.
LEVELLING – This is the most critical part of the entire process. The pool must be level within a 1/2″ all around. You can be certain the water will be level when it is put in the pool, and if the shell is out of level the water will apply uneven pressures to the fiberglass. Fiberglass is a very tough material – very difficult to damage – but the gelcoat which covers the fiberglass can easily be stressed causing very fine “spider web” cracks. Although they are unsightly they are not structurally a problem unless the stress is bad enough to create cracks through the surface. Without going into all the details, just be aware you will need a precision level – a laser is the best – and be certain the pool is level. It is also vitally important to ensure the pool stays level as water is added. If you have not prepared the excavation properly, the weight of the water in the pool can cause things to shift, so constantly be monitoring as you add the water.
PLUMBING – This is the point where you connect the pool to the pump and filter. Once all the connections are made from the main drains (always use two and join with a “T” connection), the skimmer and the returns, you should pressurize the lines before they connect to the pump, to ensure there is no leaking. We usually will pressurize to 20 PSI and ensure it holds for 15 minutes. This is a critical part of your construction. If you have a leak after the pool is complete it is a big deal to find the leak and correct the problem.
BACKFILLING – As you add water to the pool, you must be certain there are no voids under the bottom of the pool. Get into the pool and walk around. The bottom of the pool will tend to rise until water is placed in the pool, but when you walk on the bottom of the pool, you should feel the bottom of the fiberglass firmly touch the bottom of the excavation. If it does not, even when you jump a little, then there is a void that must be filled, as the weight of the water will push the fiberglass down into a depression in your pool. As you continue to add water, you continue to backfill, carefully watching the sides of the pool for any bowing. Once the backfill is complete the water should be up to about the middle of the skimmer, and you can start your system running. We will not usually add salt to the water until the pool has been cleaned and the water balanced. You should add chlorine, however, and we will put a number of solid chlorine tablets in a floater and keep that in the pool to prevent algae growth. If you let the pool go green before it is complete you will add a substantial amount of work getting the pool water clear and usable.
POURING THE CONCRETE COPING AND THE DECKING – At this point you are almost complete, but your decking is a very important part of your construction. If you are going to use stone coping or pavers for your pool, that is another part of construction and we will address that in another post. To get the concrete cantilevered coping, you will need special forms. They are available from a company called “Stegmeier”, and will require some skill to apply. We strongly encourage you to use cantilevered coping on your pool. We recommend at least four feet of concrete decking around your pool, and if you decide to build a patio that will connect to your pool decking, now is the time.
This is a bare outline of what is involved in building your own fiberglass swimming pool. It is not a task for anyone without some knowledge of construction, and as in all things there are “tricks of the trade” we have learned while building hundreds of swimming pools. I have not addressed the problem of how to handle groundwater which can be a very large problem, and an area where we have expertise. If you find yourself in a difficult situation, or are unsure of how to handle something, we offer a consultation service where we will come to your jobsite and give direction, or where we will visit at pre-decided intervals to ensure everything is correct before you move on.
Call if we can help – Frank