Framing material and sizing has changed for tall walls, theses changes in Minnesota law is for the better.
Load bearing walls exceeding the 9′ height fall under a new law. The higher the wall, the better quality the wall this may mean thicker the studs.
Included in this new law you no longer can use Utility grade, Standard grade, No.#3 grade or Stud grade lumber of any species are not permitted. The change in law is because of wind resistance against the exterior tall walls.
Using a better species of wood than SPF (Spruce, Pine, Fir) will make a stiffer wall. SPF is the cheapest wood species that you can buy.
Classification of common grade lumber. Common grade boards generally contain more knots than the select grade. Common grade is divided numerically from 1 to 5 with 1 being the best in appearance. No. 3 and No. 4 common grades are most frequently used for such applications as sheathing or sub-flooring.
Lumber grade numerical system changes title when it is shipped to large discount stores. Having changed to names the consumer has know idea what he or she is buying. Changing the name the discount stores are able to sell more product to unsuspecting customers.
Economy is the lowest grade available. This is usually junk wood, damaged material taken off of railcars. You can get a lot of twist, wane, and huge loose knots with economy grade lumber.
Utility is the next grade up in quality from economy. The discerning consumer can usually find a few useful pieces of lumber at this grade. One of the functions in large commercial lumberyards is buying utility grade lumber in bulk and upgrading it to ‘stud’
Stud grade, as implied by the name, is the most common grade used to build the framework of houses. Thus, the electronic device used to find lumber under drywall in a house is called a stud finder. Since the primary purpose of stud grade lumber is to hold up a house, very little twist is allowed, although you can have large amounts of wane and large knots.
Standard and better grade is similar to stud grade. The difference between the two is not so much in the size of the knots or the amount of splits or wane allowed, but in the fact that standard and better grade is used for lumber that is 12 feet and longer while the stud grade is used for 10 feet and 8 feet pieces in grading.
No.2 and Better grade. This grade usually allows for smaller-sized knots and a minimum of wane and splits.
An even finer quality of wood is 1 and better. This is the crème de crème of lumber and should consist of small, sound and tight knots, only inches of splits, and practically zero wane.
Above 1 and better is select grade lumber. This is an even higher quality than 1 and can be used for high-end decorative purposes. Examples of this would be western red cedar, spruce shiplap, and tongue & groove wall paneling. Having mentioned that as an example, great effects can be had using lower quality cedar as paneling, incorporating its defects to achieve a western, weathered look.