Looking to add another slider
 

We have a villa with a double slider, but would like to open the area to the pool by adding a third. Has anyone had this done, by who, and approx. cost to do?

You can probably do this, but, my suggestion, contact the county building department, and get your house plans, then:
1. Check with ARC, you are probably OK, but a phone call would be a good idea.
2. Check with building dept, existing block (or stick) walls are not designed with headers, so at a minimum, some form of header will be needed.
3. You will need one of the larger contractors (IMHO) for this type of project.
4. Be prepared for lots of dust and dirt
There have been multiple reports of people doing this type of work on their homes, just be sure that whomever you hire has experience, and that everything is done to code.

BTW, the Sumter County building codes were revised June of this year.