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Discussion Starter · #1 · (Edited)
I have a 4" concrete slab (ground level) in good condition (poured about 5 years ago). It slopes 2% away from the house. I want to build a floating deck next to the home, it will be 23.5' x 22' (the slab covers most of this area, except the deck will extend 2 or 3 feet past this border on two sides, other two sides butt up to house). The finished deck height is 14.5", I have 3/4 IPE decking I will run perpendicular to the home (23.5' dimension). I have looked at few options to attach to the concrete:
1) Deck Block (pre-grooved for 2x material). It looks to have a 6" distance from slab to bottom of 2x material. If I use flush beams with 2x8 joists/beams, I would be at 14" finished height which I am okay with. I would then pour piers any area the deck protrudes past the slab. I would need to cut out the deck block to allow the 2-2x8 PT for the 3 beams
2) Use a Simpson BC ZMAX Galvanized Post Base. I don't see it recommended in any of the Simpson literature, but have seen a bunch of content where installers use these and anchor them to the existing concrete for low-level, floating decks. Again, I would use standard poured footings outside of the slab. There are heavier duty ones too I could use (E-Z Base Black Powder-Coated Post Base).

Any idea the best option here for connecting to the slab (in San Jose CA, don't get frost, so don't expect the slab to be moving, but would rather not attach a ledger to the home, just in case)?

Also, any guidance on the proposed framing for this picture frame deck (see attachments?) I am using 3, 2-2x8 flush beams, following cantilever, joist and beam guidance from the Deck Construction Guide (<1.5' cantilever on joist/beam, < 11'1" joist span and <5' for beam supports). I have some split beams on the drawing, but could just pay more and order 23' ft material, same for the rim joists. I'd rather split them, but get's a little tougher, rather pay more and make it easier...

Also note, the piers would be centered on the beam, just offset them so could see them in the 3D photo. I would attach them with the Simpson post cap. I assume I need to use 6x6, even for this low of a deck? Or could I get away with 4x4. Again, the guidance looks to be 4x4, but this is a really low deck.

Thanks!
 

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Discussion Starter · #3 ·
It looks like 7 3/4" is the maximum step-down from California Residential Code for non-egress. It doesn't explicitly call out decks or a minimum, but local hand-outs in nearby counties suggest the same 7 3/4" with no min specified.

I thought about this some more, maybe I should just attach a ledger to two sides of the home and cut-out the concrete in the sections I need to so I can pour footings. If I switch to 3-2x8's on the beams, I can get away with a lot less footings (maybe 3 or 4 in the concrete slab area, see attached).

Any thoughts? Much appreciated!
 

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retired framer
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It looks like 7 3/4" is the maximum step-down from California Residential Code for non-egress. It doesn't explicitly call out decks or a minimum, but local hand-outs in nearby counties suggest the same 7 3/4" with no min specified.

I thought about this some more, maybe I should just attach a ledger to two sides of the home and cut-out the concrete in the sections I need to so I can pour footings. If I switch to 3-2x8's on the beams, I can get away with a lot less footings (maybe 3 or 4 in the concrete slab area, see attached).

Any thoughts? Much appreciated!
Is it a slab house or will you be going to wood against the house?
 

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Discussion Starter · #10 ·
Thanks for your help, I appreciate it. I got the updated drawing, and cut 2' x 2' holes through the concrete slab this weekend, wasn't too difficult.

My ledger is on the right wall, the bottom wall is very close to the house, but I don't need any structural attachment to the home. What is the advise in that narrow of a space? Should I install my rim joist to the home to ensure I have proper flashing? Else, I could just leave a gap of an 1" or 1.5" from the rim joist to the wall with the decking hanging over 1/2" or so. It would be covered by the siding, so visually will look okay, just not sure the best way to prevent water intrusion. Any thoughts?
 

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retired framer
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Thanks for your help, I appreciate it. I got the updated drawing, and cut 2' x 2' holes through the concrete slab this weekend, wasn't too difficult.

My ledger is on the right wall, the bottom wall is very close to the house, but I don't need any structural attachment to the home. What is the advise in that narrow of a space? Should I install my rim joist to the home to ensure I have proper flashing? Else, I could just leave a gap of an 1" or 1.5" from the rim joist to the wall with the decking hanging over 1/2" or so. It would be covered by the siding, so visually will look okay, just not sure the best way to prevent water intrusion. Any thoughts?
Free standing is better for the house. It does come with a few buts.

The back for around the house to five feet away was likely disturbed when the house was built so the footings have to go at least as deep as the house footings

Free standing on posts can be wobbly but that can be solved with some of the concrete pies to be high enough to do away with the posts.
 

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Discussion Starter · #12 ·
Well, I still want to attach a ledger to the right side, I don't want to dig up and do more footings. I got 5" structural screws and will attach to the sheathing + rim joist.

My question was specifically on the bottom of the drawing with the two doors, however I just realized that I didn't put a post beside the foundation (which is the older t foundation that only goes down 12" below grade) so it will need to attach to my home for structural support for my beam.
 

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retired framer
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Well, I still want to attach a ledger to the right side, I don't want to dig up and do more footings. I got 5" structural screws and will attach to the sheathing + rim joist.

My question was specifically on the bottom of the drawing with the two doors, however I just realized that I didn't put a post beside the foundation (which is the older t foundation that only goes down 12" below grade) so it will need to attach to my home for structural support for my beam.
You don't leave the siding in place and screw thru, that is a leak and rot problem for sure.
 
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