a)  Identify actual and nominal lumber sizes 

Nominal size is general description of rounded off dimensions. This is unique to the imperial system in which the sizes are stated in nominal formats. The actual sizes are always less than the name implies. The following table shows this system.

Important : Always draw the actual size. In notations, write the nominal size.  In metric notations nominal size is totally ignored and actual dimensions in mm.  are used. This value is equal to 25.4 times the actual size of lumber rounded off to the nearest millimetre. 

 b) Describe wood framing members

• Floor

  • Joists

  • Beams

  • Columns (posts)

• Roof

  • Roof joists

  • Rafters

  • Trusses

• Wall

  • Studs

  • Plates (top & bottom)

  • Lintels (headers)

  • Cripple studs

Floor

•  Floor joist

The rough lumber when used in framing, are named and referred with specific terms defining their functions. The main members are the floor joists which are placed at 16" on center starting at the either side of the foundation walls. By doing so, the plywood sheets forming the sub floor, always end at the middle of  joists. This leaves the other half of the joist thickness for the next sheet.  The Figure 2 illustrates this layout.  Also note the staggered placement of the plywood sub floor. 

The distance from one end of the joist support to the other end is called joist span.  The joists are minimum 2x6 in size and they are required to be of   Grade 2 or higher.  The size can be determined by checking the Joist Span Tables in the National Building Code.  At mid span of the joists, 2 pieces of 2x2's or metal brackets are used to minimize the deflection and these are called cross bridging.  See Figure 1 for member names and construction.

The openings within the floor are framed as illustrated in both Figures 1 and 2.  If the edges of the opening are not coinciding with the spacing of the joists then, two extra joists are provided on either side. These in return, support the edges of the joists cut off to make room for the opening.

Note the staggered pattern of the plywood sub floor and the mach at joist centres with the edges of the plywood sheets.

Construction Illustrated - Joists

•  Beams

Beams are used when the required span for the floor joists exceeds the allowable span for the floor joists. By adding a beam, we add an internal support that shortens the span for the floor joists.

Construction Illustrated - Beams

•  Columns (posts)

Columns are used when the required span for the beam exceeds the allowable span for the beam. The column provides an internal support for the beam that shortens the beam span.

Roof

• Roof joists

Roof joists are used only when the roof is flat. They are like floor joists.

• Rafters (stick framing)

    Selection of roof framing members are also possible by use of national Building Code  span tables similar to the ones you have seen in floor framing. Please note the definition of terms listed below.  Incorrect use of terminology will result incorrect use of tables. You will notice there are several tables for members like roof joist and the rafters. Note that at the top of each table a different loading limit is stated.

 Framing schematic and terminology

Construction Illustrated - Rafters

• Trusses

Trusses are engineered and manufactured by a Truss  company based on information provided by the designer regarding

• span width
• roof slope
• size and shape of roof

Most builders today use pre-engineered trusses as forming and shaping roofs can be a complicated affair.

Using trusses also provides more flexability in interior layout as trusses can span a further distance than stick-framing and therefore often do not require a bearing-wall.

• Read through the following documents from the Wood Truss Council of America.
• You will not be able to print these documents as they are protected from printing by the writer.

Truss Configurations

How to Read a Truss Design Drawing

Construction Loading - Do's and Dont's

Wall

• Studs
• Plates
• Lintels (headers)
• Cripple studs

        Construction Illustrated - wall members

Additional Information (click on links below):

• Studs
• Interior stud spacing
• Exterior stud spacing
• Wall support

a)  Use steel handbook 

b)  Identify steel shapes 

c)  Use conversion tables to convert units 

d)  Draw steel shapes

a)  Balloon framing 

b)  Platform framing 

c)  Describe roof stick framing 

d)  Describe roof trusses

a)  Identify roof types 

b)  Describe roof pitch 

c)  Identify stick framing members 

d)  Use truss manufacturer drawings

a)  Use Building Code span tables 

Click HERE for CMHC span tables

b)   Select appropriate joist sizes 

You will need the following information to select joist sizes:

• Condition (general or special [bedrooms])

• Grade of lumber

• Bridging and/or Strapping

• Spacing

• Unsupported length

c)  Select appropriate Built-up beam size

You will need the following information to select beam sizes

• Grade of lumber

• No. of floors to support

• Size of supported joist

• Unsupported length

a)  Draw joists beams and posts in schematic representation 

b)  Use appropriate annotation to identify framing members 

c)  Apply appropriate dimensions to framing members