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Q: cantilevered second floor decks ( Answered,   0 Comments )
Subject: cantilevered second floor decks
Category: Miscellaneous
Asked by: fitter-ga
List Price: $20.00
Posted: 22 Dec 2002 03:18 PST
Expires: 21 Jan 2003 03:18 PST
Question ID: 132379
I would like to put a deck off my second story master bedroom. I'm
worried about water entering the house where my joist's enter the
outside wall. What is the best way to flash this area to be sure the
is no water damage in the future?
Subject: Re: cantilevered second floor decks
Answered By: hlabadie-ga on 22 Dec 2002 22:43 PST
These sources should cover the subject.

Flashing (illustrated .pdf)

Tech Hotline No. 0297-E
Flashing and EIFS$file/flashings.pdf

"Flashing Around Deck
Junctures with Wall Cladding

Where decks adjoin wall construction (Figure 1) the ledger board and
the attachment of the deck ledger board to the structure must be
flashed above, below and to the sides of the deck to keep water from
entering behind the cladding. In this case a combination of metal and
flexible membrane flashing are used. The flexible membrane flashing is
used because it is “self-sealing” around penetrations, for example,
where the deck is attached to the structure.
End dams prevent water from getting around the ends of the deck and
behind the cladding. The deck construction is effectively isolated
from the cladding with flashing."

Illustrated guide to deck construction

Deck Construction  - General Methods

"Attaching the ledger to your house may require that you remove a
section of siding. However, if your house is brick, block or stucco
you'll trade off the time making the holes for your bolts. To remove
wood or wood composite siding, first mark the amount of siding to be
removed. Measure at least 6-8 inches above where you intend to mount
the ledger board. Next cut along your marks with a circular saw.
Finally, use a pry bar to  pry off the cut siding.

It's a good ideal to add flashing at this point. Properly flashing the
ledger with aluminum or galvanized flashing may save you thousands of
dollars in the future. Never-the-less, we'll flash again after we've
attached the ledger for good measure."

"Before continuing optionally flash the ledger using metal or aluminum
flashing. It's a good idea to flash at least 6 inches above the ledger
so that the siding overlap the flashing. Failure to flash properly may
result in massive water/moisture damage to your house frame in the
ensuing years."

Another illustrated guide to deck construction (with links to other
parts of the guide)

Wood in the Landscape: Decks Part III

"Whatever the method of connecting the joists, the ledger should also
receive a "Z" flashing strip that tucks under the wall siding, runs 90
degrees out over the top and 90 degrees down the face of the ledger,
preventing water from penetrating the rim joist or sill."

Deck Code Specifications for Lake Zurich

Joist flashing product (not an endorsement)

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