I think I got lied to at the big box store
 

I’ve got a question about lumber grades. Is there such a thing as #2 & Better lumber marked Stud? If you want to know the long story about why I’m asking, continue reading.

I’m building a storage shed. Since it’s small I’m able to use 2x4’s for joists & rafters to keep the cost down as long as it’s #2 grade (according to AWC’s online span calculator). I then looked at Menards website & found 2”x4”x8’ #2 & Better lumber at a good price, which is what I needed for my rafters (http://www.menards.com/main/building...358-c-9513.htm). I went to the store & bought the lumber. After I left the store I noticed the boards were all stamped stud. I went back & told them that I thought I was given the wrong lumber. I looked at the receipt & it said STUD/#2&BTR. They said that the SKU’s matched up (which they did) and that all of their studs were #2 or better. That didn’t sound right but I was in no position to argue with the guy that sells lumber for a living. I looked around and found some 8’ 2x4’s stamped #2, so I said I wanted to return what I had & get those instead. They said those were Premium Studs. I said as long as they say #2 on them I’ll take them. I went in the store to perform the transactions & when I returned to the truck they had already loaded the “correct” lumber. When I got home and started unloading the lumber I found that only a few of the boards were stamped #2, the rest were stamped Stud and Premium. I thought that was a big difference in strength between stud grade & #2. Am I wrong or did I get lied to?

There going to work fine.
I never would use 2 X 4's for rafters though. Guess your not planing on any over hang over the outsides? Far better to allow for an over hang but you would need at least 2 X 6's to do it.

Depends on how wide he is building the shed, 2X4s will be fine on some sheds that are not too wide.

Around here #2 and better is a higher grade then stud grade. I'm in canada.

From Wiki
"Based on the WCLIB grading rules,[1] there is only one grade of stud: STUD. A stud is graded for vertical application, and its stress requirements and allowable visual defects reflect that application. A stud is most similar to a #2 grade, which is held to a higher standard during grading. The biggest difference between the two is the frequency, placement and size of knots and overall allowable wane."

http://en.wikipedia.org/wiki/Wall_stud

The shed will be 12’ wide. With a 5:12 roof the rafter span will be around 6’4”. American Wood Council’s calculator says #2 2x4’s will span 7’6” (SPF, L/240 deflection, 24” spacing, 20 psf live load, 10 psf dead load). I was going to go with an 8” overhang. I figured I’d have to be conservative with my birdsmouth but I didn’t see any reason why that wouldn’t work. Is there something I'm overlooking?

What I’ve learned is that, like mae-ling posted, a stud is graded for compression loads only, i.e. no bending. According to AWC, #1/2 SPF 2x4” design bending strength is 1886 psi, while SPF stud 2x4 design bending strength is only 1067 psi. That’s quite a difference.

Not going to be much left to the board after the cut.
See if this helps.
http://www.blocklayer.com/Roof/GableEng.aspx

If the birds mouth is cut correctly the 2X4 will support as if it had never been cut.

That's a pretty slick calculator! I see what you're saying about the cutout. I had thought I would just make the notch really small, but that may not give me much room for nailing it. Maybe I can use some blocking to give me more area to nail to? Or just use metal ties?

About that..... ; http://www.kolteslumber.com/lumber_grades

You only need 1-1/2" of bearing under the rafter, either birds-mouth or wedge, first sentence;http://publicecodes.cyberregs.com/ic...?bu2=undefined

You may have trouble finding your "stud" grade lumber in that last Code link (scrolling down) for rafter/c.j. spans, though...

Gary

how do you have a link for everything GBR!! you are just amazing

In my area we have to install these to every rafter. The old style narrow twisted ones have been discontinued by Simpson.
http://www.bing.com/images/search?q=...5FF81E&first=1

Thanks, everyone, for the help. I'm going to buy some new lumber for the rafters so I know what I've got. I'll go with small 1-1/2" birdsmouth & rafter ties. That'll leave me with 3" of rafter to support the 8" overhang.

Stud grade is below #3, man I thought it was above, really not to be used for anything but studs. It is graded for the vertical load only.

My library is around 1200 links relating to the way I build and (categorized) proving a point when I make a statement, LOL. Had a lot of time off from work in this lousy economy... I love to research the links at the end of written papers or reported tests on subjects that interest me in "References". I only save the better ones and only use the direct ones.

Gary