Lumber grading?

[JavaMan]

Pardon my ignorance (which is why I'm asking), but what is the difference between #1 and #2, etc...?  And how can I tell, if what I'm looking at isn't labeled?

Thanks

[MountainDon]

All dimensional lumber bought new in lumber yards and home centers should be stamped.

something like....



That tells us that its from mill #12, grade #1 or better, seasoned - green (unseasoned in other words, 19% or more moisture, douglas fir - larch, with a western wood products assoc logo/trademark.

Have a look at the links below for more. Note that eastern woods are /may be marked differently. If the piece you have has no marks there's no real way to know for certain. Most common lumber on the racks in or big piles is #2 & better.

http://www2.wwpa.org/SERVICES/QualityServices/GradeStamps/tabid/434/Default.aspx

http://www.greatnorthernlumber.com/lumber_grade.html

http://www.nelma.org/index.php?module=StaticContent&func=display&scid=11

[MountainDon]

Softwoods and hardwoods are graded differently.

Common softwoods:

No. 1 (Construction)
Moderate-sized tight knots. Paints well. Used for siding, cornice, shelving, paneling, some furniture.

No. 2 (Standard)
Knots larger and more numerous. Paints fair. Similar uses as No. 1.

No. 3 (Utility)
Splits and knotholes present. Does not take paint well. Used for crates, sheathing, subflooring, small furniture parts.

No. 4 (Economy)
Numerous splits and knotholes. Large waste areas. Does not take paint well. Used for sheathing, subflooring, concrete form work.

No. 5 (Economy)
Larger waste areas and coarser defects. Unpaintable. Applications are similar to No. 5.



Grades for Dimension Lumber

2" x 4" and Wider                            2" x 4"                                               Posts, Timbers, Beams,  etc.
Select Structural                             Standard and Better (STD&BTR)                       Select Structural
No. 1                                            Utility and Better (UTIL&BTR)                     No. 1 Structural (Douglas Fir)
No. 2                                             STUD (10' max)                                     No. 1 SR (southern pine)
No. 3                                                                                                      No. 2 SR (southern pine)
No. 2&BTR      
No. 3&BTR      

[bayview]

   Don't make an assumption that all grading is equal . . .   

    I purchased unseen, for delivery, #2 pine 2X6" material from my local lumber yard for framing walls.   Most of it looked like end slabs from the mill.   Some actually had bark and the knots went almost completely through.  Was end stamped #2.   I sorted through and kept about half.  Returned the rest.   I hand sorted and purchased the rest from Lowes.   Same "grade".   I could have used it for furniture!

/

[MountainDon]

  Don't make an assumption that all grading is equal . . .  
Same "grade".   I could have used it for furniture!

One of the key things there is to compare equal items.  
Lumber stamped with a plain #2 is not the same as lumber stamped #2 & BTR (better)
The #2 & BTR could be as bad as the #2, but there's also a good chance that it will be BTR.

Around here most of the common lumber is marked #2 & BTR.    SPF, Hem-Fir  and  Doug Fir - Larch

[JavaMan]

I wanted to say thanks for all the great info about this subject.  I learned way more than I expected to about grading.