Does the granite countertop on my deck require separate footings?

Question

If I want to have a granite countertop as a table on top of my deck, do I need to support the 4 corners with actual footing, like 4x4 with concrete? Or it is possible to just bold the 4 legs on the side of the joists?

I have not weight my granite yet but according to this, it is 12.8 lbs sq ft

http://www.allstilesinc.com/granite-tiles-faqs/41-granite-pre-sales-questions/70-how-much-does-granite-weigh.html

Mine is like 3' x 9'

I am inspired by this, as I have no design yet.

I don't have the grill in my case but the countertop will be close to the railing. So for 4 corners of the 9 foot long countertop, are they supported by footing below? Or the legs are just standing on top of the joists underneath? UPDATE 1

This is a free standing deck. Conveniently, two legs of the countertop if supported by the posts already. So the question is do I need the other 2 legs supported by posts? Or can they just sit on top of 2x8 joists that are on top of 4x8 beam?

Answer 1

Assuming your deck is somewhat modern and properly designed and built, it can easily handle a live load of 13 pounds per square foot (no extra footings required, no need to worry about aligning the table legs over joists, etc).

That said, I am assuming your deck is somewhat modern and properly built. You should consider paying a structural engineer to take a look at your deck (especially the ledger connection to the house, which is a typical weak spot). That would be a lot cheaper than pouring new footings and going crazy overbuilding it, plus it will give you a piece of mind. You might be surprised how inexpensive a structural engineer costs to take a look at your deck and give an opinion.