I think I got lied to at the big box store

nnewman · 10-08-2012, 10:07 PM

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?

joecaption · 10-08-2012, 10:44 PM

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.

**BigJim** · 10-08-2012, 10:53 PM

Quote:

Originally Posted by joecaption

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.

mae-ling · 10-08-2012, 11:03 PM

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

nnewman · 10-08-2012, 11:22 PM

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.

joecaption · 10-08-2012, 11:27 PM

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

**BigJim** · 10-08-2012, 11:43 PM

Quote:

Originally Posted by joecaption

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.

nnewman · 10-08-2012, 11:51 PM

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?

**Gary in WA** · 10-09-2012, 01:47 AM

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

federer · 10-09-2012, 03:07 AM

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

joecaption · 10-09-2012, 11:03 AM

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

nnewman · 10-09-2012, 12:02 PM

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.

mae-ling · 10-09-2012, 12:08 PM

Quote:

Originally Posted by GBR in WA

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

Gary

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.

**Gary in WA** · 10-10-2012, 10:36 PM

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