|
|
|
|
|
Joists
Sawn Lumber Sizes
Sawn lumber used as joists ranges in common thicknesses from 2 to 4 in. (51 to 102 mm) and in depths from 4 to 12 in. (102 to 305 mm) They are the most economical and easily installed secondary framing members for floor and roof construction in spans up to approximately 23 ft. (7m)
Actual sizes for design as compared with nominal sizes are given in NDS Table 1A, using dry sizes for design in all conditions.
Species and Grades
Southern Pine, S-P-F, Hem-Fir and D.Fir-L are most likely to be stocked by lumber yards, but other species may also be on hand. In the 2 in. (51mm) thickness, the most readily obtainable material is No.1 or No.2.
MSR Grades
Some Machine Stress-Rated grades are also readily available in widths up to 8 in. (203mm); wider material may not be available and suppliers tend to carry a limited range of grades. Joists in 2 in. (51mm) thickness can usually be obtained kiln-dried (specify S-Dry) to a moisture content of 19% or less. In the 3 and 4 in. (76 and 102 mm) thicknesses, choices of species and grade is more limited. These thicknesses are generally surfaced in the green condition (S-Grn) and are not obtainable as MSR lumber.
Multi-ply Joists
The program includes a database of 2" thick joists to be used in multi-ply applications, limiting the number of plies to 2. This allows you to double up the joist members to deal with heavy loading requirements.
LVL Joists
Sizer includes a database file containing the same LVL materials as the beam database, to allow for LVL in a floor or roof system. This is a multi-ply database, with a limit of 2 to the number of plies.
Stud Walls
Sizes
Lumber used in stud wall systems has a common thickness of 2 in. (51mm) and ranges in depth from 4 to 8 in. (102 to 203mm). Stud grade lumber, however, ranges in depths from 2 to 6 in. (51 to 152mm); the smaller sizes are used mainly in partitions. For depths greater than 6 in. (152mm), another grade must be specified.
Sheathing Requirements
In stud walls the members are spaced no farther apart than 24 in. (610mm) to take advantage of load sharing. Usually the spacing is 16 in. (406mm) or less. Stud wall systems are typically sheathed by plywood, waferboard, oriented strandboard or drywall. The sheathing is nailed to the narrow faces of the studs (on at least one side) along the entire length of the stud, thereby preventing buckling about the weak axis.
Note: Studs are susceptible to buckling if heavy loads are applied prior to installation of the sheathing.
Multi-ply Wall Studs
The program includes a database of 2" wall studs to be used in multi-ply applications. This allows you to for example double up the stud members to deal with heavy loading requirements.