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Re: FW: Ceiling joists/rafter ties IRC R802.3.1

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That's a good detail, but it isn't practical where
R-30 insulating batts need to be laid in between the
ceiling joists.

The one local builder actually making an effort to
comply with code requirements is specifying 1x4
tension bracing nailed to the side of the rafters at
4ft o.c.  It doesn't necessarily meet lateral thrust
design requirements, but it meets the very minimum
specified in the IRC.  And that's more than anyone
else is doing. 

I could see a homeowner cutting the bracing out of the
way to make room for storage, HVAC equipment, etc.

Jim Wilson

--- AWC Info <AWCInfo(--nospam--at)afandpa.org> wrote:

> The Wood Frame Construction Manual (WFCM) provides
> diaphragm capacities for
> gypsum sheathing (WFCM Supplement Table 2C) of 70
> plf.
> http://www.awc.org/Standards/wfcm.html
> 
> Another publication on our website, Details for
> Conventional Wood Frame
> Construction http://www.awc.org/pdf/WCD1-300.pdf
> shows a detail in Figure 52
> that might be helpful.
> 
> There's been no testing that I'm aware of. 
> 
> HTH
> 
> Buddy
> 
> 
> From: Jim Wilson <wilsonengineers(--nospam--at)yahoo.com>
> Subject: Re: FW: Ceiling joists/rafter ties IRC
> R802.3.1 
> To: seaint(--nospam--at)seaint.org
> Buddy,
> That helps a lot considering it comes from the
> "source." As Jordan alluded to, are there any
> acceptable means of tieing roofs by means other than
> a
> double layer of rafter tie? I.e., gypsum drywall, 
> diagonal struts, wall top plates in strong axis
> bending, etc. And by acceptable, I mean by the code
> or by testing and development of prescriptive-type
> guidelines. 
> Thanks for the info!
> Jim Wilson
> --- AWC Info <AWCInfo(--nospam--at)afandpa.org> wrote:
> > If it is a hip-beam system, there is no thrust...
> So
> > it only needs to be
> > tied together to resist out-of-plane wind loads...
> > Analogous to a ridge beam
> > system.
> > 
> > If it is a hip rafter system (conventional
> > construction), it needs to be
> > tied together in both directions because the hip
> > rafter is just a connection
> > point... Analogous to a ridge board system.
> > 
> > HTH
> > 
> > Buddy
> > 
> > John "Buddy" Showalter, P.E. 
> > Director, Technical Media 
> > AF&PA/American Wood Council 
> > 1111 19th Street, NW, Suite 800 
> > Washington, DC 20036 
> > P: 202-463-2769 
> > F: 202-463-2791 
> > http://www.awc.org 
> > 
> > The American Wood Council (AWC) is the wood
> products
> > division of the
> > American Forest & Paper Association (AF&PA). AWC
> > develops internationally
> > recognized standards for wood design and
> > construction. Its efforts with
> > building codes and standards, engineering and
> > research, and technology
> > transfer ensure proper application for engineered
> > and traditional wood
> > products.
> > 
> > ********************* 
> > The guidance provided herein is not a formal
> > interpretation of any AF&PA
> > standard. Interpretations of AF&PA standards are
> > only available through a
> > formal process outlined in AF&PA's standards
> > development procedures.
> > 
> > ********************* 
> > 
> > > 
> > > From: Jim Wilson <wilsonengineers(--nospam--at)yahoo.com>
> > > Subject: Ceiling joists/rafter ties IRC R802.3.1
> > > To: seaint(--nospam--at)seaint.org
> > > IRC R802.3.1 Ceiling Joist and rafter
> connections:
> > > 
> > > "Where ceiling joists are not parallel to
> rafters,
> > subflooring or 
> > > metal straps attached to the ends of the rafters
> > shall be installed in 
> > > a manner to provide a continuous tie across the
> > building, or rafters 
> > > shall be tied to 1-inch by 4-inch minimum-size
> > crossties."
> > > 
> > > Does this apply to the secondary direction in a
> > > hip-framed roof? Some inspectors insist so, some
> > > don't know, some don't know that they don't
> know.
> > > 
> > > I've never seen it applied this way in the
> field,
> > but
> > > one prominent local builder has been specifying
> > > two-way ties on their hip-roof structures. I
> would
> > > like to either back them up, or save them the
> > effort
> > > and the consumer the added cost and
> inconvenience.
> > > 
> > > Thanks in advance.
> > > 
> > > Jim Wilson, PE
> > > Stroudsburg, PA
> 


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