So you have been considering a swimming pool and have met with the gunite pool builder. Lets see if she told you everything?
Did you know these 7 traits of concrete pools?
- Incompatible with salt – That’s right folks. Concrete (Gunite and Shotcrete are just concrete placing methods) pools are not compatible with salt. The concrete pool dealers will tell you they are. But this is for a reason; they will sell you a new surface sooner. Salt eats away at a concrete pool in much the same way it does a concrete driveway. While this may take longer because it is dissolved, it still happens. Another reason salt eats the surface is because it is abrasive and with the water moving around so often that shell wears faster with salt in the water. By the way did you know that you would have to replace your concrete pool surface?
- Surface is a wear item, you need to replace it – Now whether or not you have salt in your water a concrete pool will need to be resurfaced. At best 7-10 years is all that can be expected. Now keep in mind the price - $15,000 to $20,000 is a good starting point for a 15’ x 30’ pool.
- Concrete cracks – As a NCMA certified mason I know this all too well. Cracks in concrete are to be expected and are considered a “feature” of concrete. When pouring a patio we can do things to hide these cracks by “pre cracking” the concrete with control joints. But in a pool this simply won’t do. So we end up with cracks where we don’t want them. Out west where the soil has less clay concrete cracks less – in pools too! But here in the north east with the freeze thaw cycles and clay content you can expect a crack failure to develop in your pool
- Hard to heat – When it comes down to it concrete is just a ratio of sand, Portland cement, gravel and water. So basically it’s just hard dirt. And we all know that the ground stays the same temperature all year round. Having only concrete (which is hard dirt) insulate you from the ground (dirt) does nothing to keep heat in. In our own tests between two swimming pools of similar size. One a concrete pool using a 450,000 BTU heater and a Fiberglass (what type of insulation do you have in your attic) pool using a 150,000 BTU heater. We found that to raise the temperature from 65 degrees to 80 degrees took the concrete pool 3 full 24-hour days and only took the Fiberglass pool 8 hours. Both were in direct sun, but only one benefited from being an insulator from the ground temperature.
- Build time – Now this can vary widely from contractor to contractor, but in general concrete pools take longer to build. A fiberglass pool with 4’ of concrete installed in a flat location will typically be ready in under 10 working days. A top Gunite builder will typically quote 30 days for the same project while most Gunite builders shy away from 30 days and commit to 90 days. In fact many gunite builders never actually build the pool themselves. Every portion is subbed out - Dig, Plumb, Steel, Gunnite/Shotcrete, Surface, Decking etc. Here at Albert Group we sub nothing. If we don't do it - we don't sell it to you.
- Surface is rough – All you need to do is stick your hand in a concrete pool then a fiberglass pool to feel the difference yourself. The smoothest concrete pool surface is a cheese grader compared to fiberglass. Do you want your kids feet to look like this after one hour or volleyball in the pool?
- Inconsistency of material used – Not all concrete is the same. If you know someone in the masonry trades ask them if every truck of concrete they have ever ordered is consistent. It’s not, that’s why it is considered an art. If concrete just always came in the way you wanted and did what you wanted it to do every time that would be great. But the fact is that you have to know how to work with it the way it comes in that batch. Everything can be a factor, humidity, drive time on the truck, was there leftovers from the last pour in his truck before he loaded you, is the truck sitting in the sun, is the project in the sun, windy, overcast, how many times did the barrel spin (there is a counter in the truck and you have to know it), did it rain last night (that would cool off the gravel).