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Cantilever balcony - to a post and beam deck

Cantilever balcony - to a post and beam deck

Cantilever balcony - to a post and beam deck

This might be in the wrong place but wanted to get some opinions. It is time to build a deck to replace a decaying balcony on my 1965 built house. Currently the untreated 2x10 floor joists extend beyond the house 6-ft. for a balcony (Photo 1).
To rebuild I will enlarge the deck by dropping a post and beam 9-ft. away from house.

How to attach the new joists to the house?

This has been addressed many times on the internet, and the consensus is to cut the cantilever joists off and install properly detailed ledger board.
I wanted to ask again about other options..

The existing joists are in decent condition (for 55-yr old untreated lumber). It appears the 2-ft. closest to house are sound, and inspection of wall-plate from interior shows no moisture damage. We only get 12-inches of precip. a year, so that plus the eve seems to have prevented accumulative moisture damage.

Two other options I am considering for attaching joists to the house, opposite a post and beam setup. Would you please opine?

1) Sister to stubs: Cutoff all but 24" of the existing joists and sister the new joists to the remaining stub out (see photo 2 for an example found on another forum and photo 3 for the existing joists).

2) Slide in new joists for full bearing: Flush cut the existing joists with wall sheathing. Remove the blocking and slide in new joists, sister new to the existing joists on the inside, replace blocking etc.

Thank you,


Photo 1 - 6'x45' balcony for replacement.

Photo 2 - An example of new joists sistered to cantilevered "stubs" (source: https://forums.jlconline.com/forums/forum/jlc-onli...)

Photo 3 - The existing cantilever joists.

RE: Cantilever balcony - to a post and beam deck

I'm personally more partial to cutting off the cantilever, installing a rimboard, then a self sealing waterproofing(blueskin or the like) and then hang the new joists off the rim board. Be sure to adequately tie the deck back to the house however so it doesn't fall away from the house.

Also, pay close attention to lateral stability along the deck. the post and beam at the 9 ft mark should have a line of bracing to stiffen it up.

RE: Cantilever balcony - to a post and beam deck

It seems the cut and rebuild is the most simple/economical way to go. I vote for it.

RE: Cantilever balcony - to a post and beam deck

If the existing joists were treated and in decent shape for 2' from the house, I would cut at 2' and then added the beams you indicated.

Since you say the existing joists are not treated, I would cut off all of them and added back new beams and joists.

The 2' at the house being in better condition is probably due to the roof overhang.

Expect a slight sag of the interior floor joists when you cut off the exterior porch. Had the joist been treated and the 2' salvageable, that would have reduced the new sag to some degree.

RE: Cantilever balcony - to a post and beam deck

Thanks for the responses.

Is it better to remove the existing blocking and cut the joists far back enough to allow a rim board that bears on the wall plate? This seems hard!

Or can one attach a ledger board to blocking? Cut joists flush at the sheathing, waterproof over sheathing and the joist ends. Then a ledger board , lagged into the blocking and add tension ties back to house structure.



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