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Replacing a vintage cantilevered deck: attaching the ledger board

zj37's picture

Hi there,

I hate being the guy that signs up for a forum and posts immediately, but I can't find a solid answer anywhere.  For what it's worth, I am a member over at Fine Woodworking, and my Dad's been a FH subscriber for decades.  Anyway...

I recently bought a 1960 split level in Seattle, with a deck that spans the entire back of the house. The deck framing is original, and the joists are in pretty bad shape. Several rotted, were sistered, and rotted again.  It varies between 6 and 8 feet in depth, and there are posts below the front edge (the backyard side). The attachment to the house appears to be cantilvered floor joists extending from under my living room/kitchen/bedroom. This is what is causing me trouble. (The joists are untreated 2x10's, fwiw)

My plan is to cut off the deck, remove the siding from the bottom of the joists to the top of the decking, then flush cut the joists to the sheathing. I would then lag bolt a ledger board to the wall, but I'm a little nervous about doing that. It seems that I would have to either bolt into the endgrain of the 60 year old, possibly dicey floor joists (some of the deck joists show rot, remember), or into the blocking that I assume is toenailed between each of those joists. Without ripping off all of the siding and pulling the sheathing off, I can't be certain what is under there. Anyone have any ideas?

Thanks, Zak

You have to open it up to (post #214943, reply #1 of 8)

You have to open it up to know what's there! And you wont know if the endgrain is rotten until you cut the joist down. This is one of those issues that can't be answered until you start the work.

Do you intend to cantilever the deck like it was before or will you support the new joists with posts to grade?

Thanks for the reply. The new (post #214943, reply #2 of 8)

Thanks for the reply. The new deck will be supported on the outside by posts to grade, and the house side will have a ledger board with joist hangers attached.

this may not be easy... (post #214943, reply #3 of 8)

Bolting into the end grain is a no go anytime. There are fasteners [simpson?] that go back and attach around the joist  itself then bolt to the ledger.. 

Better yet don't fasten to the house at all but use posts or piers against the house side as well. Space all parts of the deck with a bit of a space between the house and the whole thing will last longer, decks fastened to the house are prime spots for decay unless done very well

If you do attach a ledger to the house the flashing/standoff details are crucial or you could wind up with rot, some more.

I'm surprised the cantilever lasted this long. Hopefully you won't find a real disaster when you lookin there but don't be surprised. Using regular joists cantilevered to support a deck is mostly poor practice. Maybe entirely poor practice. 


If you don't have a good bit of experience you really, really need to do your home work here. Besides more decay there is the part about loaded decks and gravity. Got codes there? Whole 'nother can 'o worms...


Definitely more good advice. (post #214943, reply #7 of 8)

Definitely more good advice. I'd been considering making the deck freestanding, but there are a ridiculous amount of doors on the back of the house.  3 eight foot wide sliders upstairs, and one 8 footer and 2 swing doors downstairs.  How much space do you stand off of the side of the house if it is freestanding?  Also finding correct spacing for the posts against the could be interesting when dealing with the doors (and windows.)

Note that support posts don't (post #214943, reply #8 of 8)

Note that support posts don't have to be flush with the house -- they can sit 3-4 feet out.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

If the joists are sound you (post #214943, reply #4 of 8)

If the joists are sound you can use upside-down joist hangers to attach the ledger.

However, you might want to consider attaching the ledger BELOW the level of the deck, lagging it to the studs and top plate that are supporting the joist.  Then set your joists on top of the ledger or rest a second ledger with joist hangers on the one you just attached.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

We don't attach decks to (post #214943, reply #5 of 8)

We don't attach decks to houses any more at all. We set posts next to the house and build the deck off that. Much stronger, easier and less prone to rot next to the house.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

freestanding (post #214943, reply #6 of 8)

freestanding is the way to go...especially in your case where you don't have any structure (currently) to attach a ledger board to.