Why do fiberglass pools crack?
Well, we all know everything has a breaking point. The trick is getting a product where the breaking point is so far out of reach that you will never get near it. But the question stands – Why do fiberglass pools crack? There are a few different ways that a fiberglass pool will crack. I will attempt to give you my honest professional opinion here as to what I have witnessed. If you have seen something I missed please leave it in the comments. The more we all know the better off we all will be.
My top 7 reasons fiberglass pools crack.
Improper shipping support. I have seen this on a pool before and there is not much I can do about it once it gets to me but send it back from where it came from. Travelling down the road can place huge stresses on a fiberglass shell because of the bumps in the road. What happens sometimes is that a pool will be strapped improperly and this will allow significant distortion of the pool shell. Leisure pools are able to flex over one foot without damage, but they also let you know any more is not good. The cracks that form are sometimes referred to as spider cracking of the gel coat. This is unsightly and should be rejected although it poses no threat to the overall structural integrity and is only on the surface.
Improper gel coat thickness. Now this one is a strange phenomenon. Gel coat applied to thin will crack just as easily as gel coat applied to thick. I’m not a scientist, I don’t know exactly why this happens, it just does. There is a very small margin for error here so the factory must have quality control factors in place when manufacturing your pool.
Accidental Damage. Well that can be just about anything. The most common although almost nonexistent would be the run of the mill car accident. In the past 5 years I know of only one pool where the driver hit a low bridge. That will straight destroy anything so a pool is no different.
Pool shell too thin or just too weak. Some manufacturers build weak shells, it’s bad for the industry as a whole. But unfortunately that’s just how it is. If the shell is too thin or flexible it will flex past the ability of the gel coat to flex and cause a spider crack.
Low quality gel coat or even worse a gel coat alternative. Placing plastic on the inside of the pool and calling it a high end finish is getting more and more popular. Be wary of any pool that calls the inside of the pool “xyz finish”. That is not a true gel coat and has a been known to fade and just plain delaminate.
Pool not made level to begin with. If a pool shell is produced off a wood framed mold most likely that mold has warped over time. With varying humidity and temperatures this is unavoidable for these cheaper molds. The problem with that is that the factory gives the installer a set of dig plans and we dig the hole to exacting specifications. If the pool is not the shape it was designed to be the hole will be off and the pool will not be level. Once water is placed in the shell the pool will most likely find level because of the tremendous weight. This forcing of the pool into level will stress the shell and cause spider cracking at best and giant wall cracks and bulges at worst. Rumor is that one manufacturers shells are so far off that they recommend the installer use the excavator to push the uneven corners down then fill it.
Improper backfill and or installation. If you use sand you will come to regret it. Thing is, sand just is a pain to compact fully, especially 8' deep around a corner you can't see. Gravel comes out of a shovel 95% compacted and the rule is if you get to 98% you can build just about anything you want on it. Sand besides being hard to compact can wash away in wet conditions. If your pool builder says they will be using sand - run!
Notice I didn't say temprature. Cold temps have little to no affect under normal. Every fiberglass pool builder in the northeast has installed a pool in below freezing temps and they never have a problem. I remember at the end of 2010 just before Christmas breaking over 1000 pounds of ice that froze inside a pool that was waiting to get installed. I needed to get the ice out because it was too heavy to lift with it in and there was no problems smashing the ice with a sledge hammer. Thats because the gel coats and fiberglass itself have great cold weather properties. And that's why fiberglass pools are a great choice for upstate NY.
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Our company started with a simple idea: Treat people the way we’d like to be treated. Provide choices, be up-front with pricing, and give them quality features in their landscape. More than 15 years and hundreds of satisfied customers later, we continue to make good on this commitment. Pool technology has changed tremendously, opening up the possibilities for what type of pool you can have and the stonework surrounds—and all the elements that can go along with it. This has made installing great poolscapes even more enjoyable for our crew.