I would have no way to even guess without a bunch more information. That is like asking how much does it cost to build a house. Too many variables and not nearly enough information.

rpetidos... I had the same question. I am an appraiser. After having no luck on the web I checked my residential cost hand book. There it was... $11-$14 per sf of the area to enclose.

You think the poolman would have had some idea.

Average cost on building a house in Houston is $60 SF.