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Re: Ceiling Joists to Wall Stud Connections through Drywall

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Mr. Norman,
     I recently encountered a similar scenario . . . the building official
required two layers of 5/8" gypboard on the exterior side of studs framing
the stairways and elevator, uninterrupted at the floors.  My original design
assumed the floor framing, all wood I-joists, to be supported on the stud
framing.  The foundation and much of the framing was in place before the
fire protection requirement became known.
     It made no sense to me to attempt to connect a ledger through the
gypboard, so I offered other harebrained solutions . . . none of which
gained favor.  Finally, the architect was somehow able to convince the
building official to allowed the interruption of the gypboard for a double
2x header lag screwed to the wood studs; maybe the theory is that the double
2x header offers fire protection to the studs as well as the gypboard.
__________________
John P. Riley, PE, SE
Riley Engineering
20 Oakwood Drive, Blue Grass, Iowa 52726
Tel & Fax:  319-381-3949
jpriley485(--nospam--at)peoplepc.com


----- Original Message -----
From: "Drew A. Norman, SE" <DNorman(--nospam--at)dnormanse.com>
To: "SEAINT List Service" <seaint(--nospam--at)seaint.org>
Sent: Tuesday, February 20, 2001 5:55 PM
Subject: Ceiling Joists to Wall Stud Connections through Drywall


> Colleagues:
>
> An architect recently sent me two details showing light gage metal ceiling
> joists framing respectively to an existing wood stud wall and a new light
> gage metal stud wall.  This is rated construction, with drywall both sides
> of the ceiling joists and studs, and the framing is balloon (not
> platform) -- with the studs being continuous to the underside of a roof
> structure above.  Both details show a continuous track surface mounted on
> the face of the drywall and attached to the studs behind it with undefined
> fasteners pentrating through the wall board and into the studs.  The
client
> wanted me to help them specify appropriate fasteners to make these
> connections.
>
> I selected appropriate numbers and sizes of wood screws and sheet metal
> screws respectively, basing allowable loads on single shear connections,
and
> gave these to the client, modifying his details to show that the
continuous
> tracks needed to be mounted directly against the studs (e.g., that the
> drywall had to stop above and below the ceiling joists).  He has responded
> by saying that he needs to have the gyp board continuous across the face
of
> the wall (i.e., between the track and the studs) for fire safety and
> security reasons, that these kinds of "through drywall" connections are
made
> all the time, and that I must be missing something if I couldn't calc it
out
> (I told him that I did not know of an approval that would allow me to rely
> on the strength of the wall board and that I did not think it was
practical
> to design the screws to "cantilever" across the gap that the wall board
> represents).
>
> I recently had to help "fix" a similar (but, to be fair, more highly
loaded)
> connection (which I had declined to approve) for another client after it
> failed by tearing of the drywall around the fasteners (a portion of the
> drywall was removed and a ledger "ribbon" direct mounted on the faces of
the
> studs added as a repair), so I am very reluctant to advise this customer
to
> do anything except cut out the gyp board.
>
> Any suggestions?
>
> Drew A. Norman, S.E.
> Drew A. Norman and Associates
> Pasadena, California