On Sat, 5 Nov 2016 07:39:22 -0700 (PDT),
wrote:

Hey, I'm a Canadian, we don't abuse each other for making a typing error. I got my measuring tape out and the deck is 10 ft 3 inches wide and 14 ft 5 inches long.

One side (the side where the hot tub will be) is attached to the outside wall of the house.

The joists underneath are 21 inches apart. The other side is secured by 3 4x4 posts evenly spaced. Their website says it weighs 1972 lbs.

Not sure what being Canadian has to do with it. I haven't seen any of
your earlier post or replies. Regarding the weight of the tub, 1972
lbs. is either the weight of a very small hot tub -or- the empty
weight of a very large hot tub. We can't really help you without
knowing which. Also, regarding the joists being 21 inches apart, that
is an unusual distance. Do you mean 21 inches between 2 of them or 21
inches center to center? Center to center is the normal way of
measuring. Fort example, they might be spaced at 16" or 24". I'll
guess yours are 24" but my guess isn't important in the calculations.
Best of luck and enjoy the tub when you are done.

Pat