jaigordon87

My home has a 20' by 4' recessed balcony on the front of our second floor. It is water proofed and overtop of living space.

We would like to extend this by at min 2 feet creating a 20' by 6-8' balcony.

My understanding is that in order to cantilever these joists they would have to be sistered back into the house by a 3-1 ratio. this is not a concern should we open it up and be able to slide 12 foot 2x10s back into the house 5 feet (+4 over the recessed deck) and then cantilever beyond the exterior wall by 3 feet.

However, my assumption (will have to open up below to be sure) is that because this wall does not extend all the way down through the first level, that there is some sort of beam/rim joist.

If this is the case, does anyone have a solution for accomplishing this cantilever with only a 4 foot span to work with? I have seen people say that joist hangers can be employed upside down, attached to the rim joist, but I don't imagine this means I can cantilever more than 1.5' (1/4 the joist span).

I have used a local engineer in the past and will have my plan ok’d and any permit pulled by him, I just want to limit his consultation to a simple signing off.

Guap0_

If it's going to be inspected/approved by the building dept. I don't see how anyone can sign anything without the original plans & the modification plans.

Nealtw

Nice try but it doesn't work like that.
If you have 4' now by code you have another 12' inside if you add 2 ft you need 18 ft inside.

chandler48

To add, sending additional lumber alongside what you have, now, or lengthening it may run into infrastructure obstacles.....air conditioning ducts, electrical, plumbing, gas lines, etc. It boils down to this question....do you absolutely need a cantilevered deck, and do you need to extend it if you do?

__________________
Larry......
Half of Communications is Listening, and You can't Listen with your Mouth.

carpdad

It's not just the see-sawing. The outside part also has to be substantial enough to stand on its own, and be substantial enough to stand the load at the fulcrum. Regular 2x10 floor joists is not big enough to extend like you want to. Also if you extend the capacity by 2-300%, rest of the house may tip over. I don't think even another 2' extention with the floor joist you may have. You will have to find a footing, install a beam and build it like a supported structure. Also you will have to check the wall that's going to support this new floor. Window, door span headers, etc.
If you look at Frank Wrights falling water house, the cantilever patio is not that large but it is built with fairly large metal i beam.

ron45

If you need extra maybe...



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