Re: New Balcony not supported by home structure
Based on your description on some of the structural elements sounds beefy enough --- which is a good thing. You're probably aware there will need to be some hefty hardware like beam saddles and lag screws ( or bolts ) , etc..
Considering a deck of that height and size needs to be strong and sturdy enough to handle the loads that will be present --- after all you don't want people on it and come crashing down 10+ feet.
It's not clear as to why the deck won't be attached to the home --- but --- there can be advantages not to. For one , you won't have any concerns of water infiltration behind the siding from the ledger creating issues with the home's structure.
However , with free standing platforms ( or deck in this case ) there are more considerations when it comes to bracing. The taller the structure , the more wobbly it becomes. In which case you may need cross bracing ( X ) between the columns to stiffen up the structure preventing lateral movement or racking. Or at the least , brackets secured at 45 degrees with the rim joists ( beams ) and the columns ---- sizing and distance down from the top would need to be determined by someone in the know.
Also, the longer the structure the more support may be needed. At 15 feet you may be required to have 3 columns front and backsides --- depends.
There are some advantages to an attached deck when it comes to structure.
The plane of the structure that is secured to the home ( ledger ) adds rigidity , helping to reduce lateral moving. In which case many times simple corner braces at the outside columns is all that's needed.
I'm thinking you referenced that site to illustrate the method for the foundation and anchoring. As you see even with the substantial anchoring that deck is still attached.
As a recommendation --- don't have the deck flush with the bottom of the door. Since this will be free standing it will move at a different rate than the house.
Which also raises the issue of -- " However it will be attached to the house for waterproofing purposes, ... ".
Since the deck will move independently from the house and depending on the waterproofing method , it may fail because of the different movement.
When you submit your plans for the permit , many points will be addressed to meet your local building code.
Just some thoughts.
Good luck with the project. Let us know how you make out.
"" an ounce of perception -- a pound of obscure "