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Valley Stud spacing

Valley Stud spacing

Valley Stud spacing

(OP)
Does anyone use 6' O.C. valley stud spacing?  We typically use 4' O.C. but are contemplating switching to 6.  

RE: Valley Stud spacing

I've never seen 6.  We use 4.

RE: Valley Stud spacing

What is a valley stud?

RE: Valley Stud spacing

I've never heard the term either.  Do I really want to know?

Mike McCann
McCann Engineering

RE: Valley Stud spacing

Valley trusses frame overtop of other trusses to form the ridge and valleys of a perpendicular gable roof.



.

RE: Valley Stud spacing

Oh...I call that overframing.  

Mike McCann
McCann Engineering

RE: Valley Stud spacing

(OP)
The valley studs are the lumber that form the verticals in a valley truss.  Typically they are 4' o.c. just because that is how they have historically been built.  I think 6' o.c. is also adequate.  Any thoughts?

RE: Valley Stud spacing

Fooling around with a 24' 8:12 valley truss, I have problems with the peak not plating at 6'oc.  I have this problem with other spans, too.  4' oc - no problem.

Aside from that, View models valley trusses with a roller support under each vertical, so you get bigger point loads at 6' versus 4', obviously.  However, you really have trusses below the valley trusses acting more like spring supports, and they are not necessarily directly under the verticals.  

So, then it comes down to how stiff the bottom member of the valley truss is and it's ability to distribute the vertical load to 3 trusses.  In my experience, it's pretty low grade stuff.  I think I'm inclined to stick with 4'.

RE: Valley Stud spacing

(OP)
We use SYP #1 on all chords.  E=1.7E6.  Our software models it similarly, however, I have no problems in getting it to plate at the peak.  What software are you using?    

RE: Valley Stud spacing

4' oc distributes the vertical stud point loads more uniformly to the base trusses, but there is nothing wrong with designing valley trusses with larger stud spacings. Run the design with supports matching the base truss spacing (usually 2'oc), and transfer those reactions as point loads into the design of the base truss. A larger or stiffer valley truss bottom chord will more evenly distribute the reactions.

Some reduction may also be considered where the valley truss bottom chord is bevel-cut to accomodate the base truss slope.

The valley truss is a unique design and may have a 2x4 top chord even when the commons have 2x6.

Point loads <34" oc may be analyzed with the equivilent plf.
This comes from 2'oc tie-in trusses supported by a girder truss at 45 degrees.

RE: Valley Stud spacing

Is SYP #1 your lowest grade?  We use mostly SPF  for our base material, and bump up to SPF MSR for 2x4 and 2x6, and bump to #1 Dense or DSS SYP for 2x8, 10, and 12s as necessary.

I can get my valleys to plate the peak with MSR.

I am using Alpine View.
 

RE: Valley Stud spacing

(OP)
SYP#1 is not the lowest grade but it is the minimum we use for chords.  We will use SYP#3 and up for webs.  Don't typically use SPF for trusses unless the market demands it.  

RE: Valley Stud spacing

I have seen valley set studs spaced at 6' o.c., although we design them at 4' o.c.  I recommend the first valley set truss which may be exposed to wind, have a 2' o.c. spacing.

woodengineer

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