Rules of Thumb for Concrete Installations by: Editor - Rich Bergman
For installing Titan post anchor on concrete surfaces, a good ballpark is 1.5" from the edge of the concrete. With older concrete you can probably creep in a bit closer because concrete gets stronger with age. Another thing to consider is if the concrete has lots of aggregate (stone) in it. It will be stronger.
If it is a finer concrete with more Portland cement and less aggregate it will crumble easier. But in most cases concrete poured by a builder comes right of the mixing truck and is quite consistent and is made of 1" minus stone.
Pre drill the concrete using a single anchor as a template to locate the holes and be absolutely sure each hole is lined up property. You only get one chance to drill concrete holes.
If you use a long screw, like 3" or longer you should only need one in each corner. Tapcons are fine but there are lots of brands available. Drill at least 1/2" deeper than the length of the screw into the concrete.
I won an inflatable 6 person inter hot tub. I have a large deck. 12x 20 on both sides of the house. With a header to the house and the deck was built 6
I'm putting a swim spa into an inground concrete bunker and will build a deck around it. I have been advised to keep the deck joists a minimum of 6 inches