On Monday, August 14, 2017 at 11:51:24 AM UTC-5, -MIKE- wrote:
On 8/14/17 10:01 AM, tdacon wrote:
I'll take Mike's word on sealing the ledger. You're talking to
long-time classic wooden boat guys here - my friend is an
English-trained shipwright, and I've owned a classic wooden sloop for
over forty years. So we know caulk. Fresh water leaks are the death
of a wooden boat.

That was me. Cracks, seams, gaps... all need waterproofing of some type when outside unless it is fencing. Part of my company is waterproofing, so I use a LOT of elastomeric caulks to seal dissimilar materials to one another..

My advice was to not use a ledger at all. I advise to use separate
footings/posts and not have the deck physically attached to the house at
all. If digging too close to the house is a deterring issue, then you
could always put the posts 3 or 4 feet away from the house and
cantilever the joists over the beam, to the house.

I know NOTHING about building in Vermont, but I think styles of building decks are probably pretty regional. For example, the county I live in is almost 1300 square miles (!!) so that comprises a lot of area. At the southern end of the county there is a lot of black dirt, and pretty stable substrate. North of that is a wide band of very plastic soil that moves tremendously, keeping at least three hundred slab/foundation repair guys constantly busy. It is no uncommon for a house to have large sections break off and move away from the larger portion of the house. When I revamped my parent's house for sale a few years ago, they had a 1" separation of the back third of their house from the slab!

North of the city/county, topsoil barely covers rock. To make VA/FHA requirements on new homes, they truck in soil from the south end of the county to be able to meet the minimum depth requirements. Slabs are poured on top of cleaned bedrock if a engineer can determine the proper type and thickness of the underlying rock. Houses built on those never, ever, move.

So we attach our decks to the houses for two different reasons. First, the deck that isn't attached to the house can simply wander off into the yard over a period of years. And second, if the house is completely stable, why not? We get torrential rain here, followed by long periods of dryness, then drought. We have no snow melts, no ice build ups, nothing that would keep wood soaked for long periods.

That being said, I don't like the ledger detail. It is commonly used, but to me, especially considering today's inferior material quality it is a bad one. I won't use a wood ledger unless people put me in that position by wanting the lowest price on the job. I learned this while doing commercial work.

I go to one of the local welding shops and have them cut a piece of 3" angle for me to the length I need. This is usually about 16 feet or so, and costs me about $60. Then I have them punch 1/2" holes every 16". It always winds up with the total cost being about $125 for the piece, so I am guessing I am paying about $4 a hole.

I put the ledge up so it looks like a "7", so that when it is mounted the anchors are shielded from water. After the holes are marked, I put a coat of enamel on the angle while the anchor holes (3/8") are being drilled. I mount the angle and set the joists on top of it, putting blocking in between the joists. I don't nail the joists to the anything to attach, like you description, they sit on the angle, but cantilever from the last structural beam. I do tack in the bridge block, but that's it.

I have been using that detail for 30 years, and as I said it is modified from a detail I used when pouring tilt panels and attached bar joists to standing walls. Never had that detail fail, but for some reason, I am the only guy I know that uses it. I see those damn wood ledgers up everywhere, and the structure/joists toe nailed into it. Decks built that way will fail, and some do in just a few years. I can see how that would be a worthless detail is you had snow or ice on top of it.

Robert