Hip and Valley Rafter Sizing

[jar546]

Just received a response from an engineer rebutting an inspection report for a contractor. He stated that the hip and valley rafters were compliant with Table R802.5.1

This is not the first time we have had someone refer to this table.

In our opinion, we believe that the only table we know of that prescriptively covers hip and valley rafters is the AF&PA's WFCM Table 3.28

What say thee?

 

[rleibowitz]

Table R802.5.1 are for Rafter spans and doesn't reference Hips or Valleys ask the engineer to do the math L x L x W divided by 2

 

[Jobsaver]

R802.5.1 addresses common rafter spans. R802.3 gives prescriptive criteria for hip and valleys. 2006 IRC.

The contractor is due a refund from the engineer. Or, math. I am continually surprised at some of the letters we get from "engineers" where no calculations are presented as evidence to support a rebuttal.

 

[GBrackins]

WFCM is the only one I know of

 

[Uncle Bob]

R802.5.1 addresses common rafter spans. R802.3 gives prescriptive criteria for hip and valleys. 2006 IRC. The contractor is due a refund from the engineer. Or, math. I am continually surprised at some of the letters we get from "engineers" where no calculations are presented as evidence to support a rebuttal.

I agree with R802.3 (excerpt) "Hip and valley rafters shall be supported at the ridge"; This indicates that hips and valleys are rafters and therefore are covered by the same requirements as rafters. Perhaps that is what the engineer is referring to. Hope this helps, Uncle Bob

 

[Sifu]

I have never had anybody point to any table in the code book for hip and valley sizing. I usually just get the thousand yard stare when I call 'em. I have always used WFCM, don't know how you can use the rafter span tables for hip/valley sizing. I have always had a question about calling a hip/valley rafter a "rafter". Is it not a beam? WFCM has no definition for hip or valley, but it does for hip beam and valley beam. IRC has no definitions for any of them. If you compare a like size, species and condition rafter from 802.5.1 to a hip/valley beam from WFCM 3.28 they aren't very close.

 

[steveray]

R802.5.1 addresses common rafter spans. R802.3 gives prescriptive criteria for hip and valleys. 2006 IRC. The contractor is due a refund from the engineer. Or, math. I am continually surprised at some of the letters we get from "engineers" where no calculations are presented as evidence to support a rebuttal.

AMEN......

 

[jar546]

Yeah, using the IRC Tables to size hip and valley rafters makes as much sense as using it to size joists for exterior decks in wet service application. Contractors still think the IRC has all the span tables needed when in fact, the WFCM is needed for every hip/valley roof and exterior deck framing. The IRC is not an all encompassing all inclusive code for wood framed construction but not everyone gets that.

 

[peach]

One of the things I don't like about the I Codes is it's use of referenced standards rather than keeping things in the body of the code; you end up dropping big bucks to keep a current library.

Having said that, it's been so long since I've seen a hand framed hip or valley (usually a truss set), I'd have to defer that the plan reviewer did the job up front. We don't see all that many brand new wood buildings.

 

[RJJ]

hip and valleys need to be reference to WFMC or sized and seal by the DP.

 

[jar546]

Resurrection time.