Pool subsoil

[Butcher]

Curious, you mentioned that pool crete (sand/portland) is the best of the 3 bottom options for a liner installed pool. However, I have noticed most builders in the NE quote out their pools with a vermiculite bottom. Can you guys expand a little on what actually makes the pool crete a better option?....is it sturdier?...better feel?

I think if you could expand a bit on this, it would help some of us who are also following this thread make better decisions

Pink Floyd- Comfortably Numb

 

[Ohm_Boy]

Well, like anything else, I guess it's a matter of opinion. Vermiculite is used a lot. It's pretty easy to do and goes down fairly quick. I think in general it does wear faster since it's softer. It's only a few hundred PSI, if that. So..if you have weight on it, over time it will get bumps in it. It actually wont hurt anything, really. Unless it gets too bad, its not that noticable in the day time.
"Pool crete" is basically a mix of porland, sand, and some times either a bit of vermiculite or fly ash. It's more expensive to do that way, but it wont get lumpy and bumpy like straight vermiculite will. It's ~3000 psi so its really durable. On a liner change, the potential to have to re-do or repair a vermiculite floor is higher than pool crete, for sure.
I wouldnt get too worked up over the use of vermiculite over pool crete, really. Both are good options. That being said, ifa builder offered pool crete over vermiculite, I'd opt for the pool crete. But, if i liked a particular builder for price, service, etc and he only used vermiculite, I wouldnt turn him down over it.

This is actually an important point for folks having a builder put in a pool. The options often differ by region. It is usually way better to go with what the builders in your area already know and have experience installing, rather than trying to find one willing to learn a new technique for your pool build.

 

[Butcher]

Here is more info on what to use for the pool base

http://www.royalswimmingpools.com/ing_base.htm

They also mention that vermiculite is a better option for high water table areas.