Chapter 36

Sectioning Basics

Introduction• Sections

– Drawn to show vertical relationships of structural materials

• Show methods of construction for framing crew

– Before drawing, it is important to understand:• Different types of sections• Common scales• Relationship of cutting plane to the section

Section Origination• Building sections

– Result of passing the viewing plane through a structure to reveal construction methods used

• Material in front of viewing plane cannot be seen• Material behind viewing plane is projected to the

plane and reproduced in the section

Section Origination (cont’d.)• Another visualization method

– Think of the viewing plane as a giant saw that slices vertically through a structure and divides it into two portions

• One portion is removed to allow viewing of the portion that remains

Section Alignment• Drawing is read from the bottom or right

side of the page– Cutting plane

• Shows which way the section is being viewed• Arrows should be pointing to the top or left side of

the paper• If possible, should extend through entire structure• Can be broken for notes or dimensions• Can be jogged to show material clearly

Types of Sections• Full sections

– View that result from passing the cutting plane through the entire structure

– Meant to give an overall view of a specific area• Transverse section• Longitudinal section

Types of Sections (cont’d.)• Partial sections

– A section that does not go completely through the structure

– Used to show construction materials for specific areas of the structure

• Typically used to supplement full sections• Also used on complex structures as a reference for

details of complicated areas

Types of Sections (cont’d.)• Details

– Enlargements of specific areas of a structure– Typically drawn where several components

intersect or where small members are required

Drawing Scale• Sections are typically drawn at a scale of

3/8" = 1'–0"– Scales of 1/8" or 1/4" may be used for

supplemental sections requiring little detail– Partial section may be drawn at a scale of 3/8"

= 1'–0", 1/2" = 1'–0", or 3/4" = 1'–0– Details are typically drawn at a scale of 1/2" =

1'–0" through 3" = 1'–0"

Drawing Scale (cont’d.)• Factors that influence choice of scales in

drawing sections:– Size of drawing sheet– Size of project– Placement of section– Purpose of section

Drawing Scale (cont’d.) • Primary section

– Typically drawn at a scale of 3/8" = 1'–0"• Main advantage is ease of distinguishing each

structural member• Other sections are drawn at 1/4" = 1'–0"

– By combining drawings at these two scales:• Typical information can be placed on 3/8" section• 1/4" sections show variations with little detail

Representing and Locating Materials

• Type of section drawn will dictate:– Amount of information displayed

• Smaller the drawing scale, the less information

– How the material will be represented• Details require more attention to line contrast and

the use of more varied line weights

Representing and Locating Materials (cont’d.)

• Using line contrast– Details require a minimum of four different line

weights to provide contrast between materials– Line weights vary depending on scale– Goal of each section is to have good contrast

• Thin lines represent construction materials• Thick lines represent structural materials

Representing and Locating Materials (cont’d.)

• Representing material– Method used depends on drawing scale

• Wood, timber, and engineered products• Steel• Unit masonry• Concrete• Glazing• Insulation

Representing and Locating Materials (cont’d.)

• Locating materials with dimensions– Vertical and horizontal dimensions may be

placed on sections• Partial sections and details generally show only

vertical dimensions• Small-scale sections use of dimensions depends on

the area represented

Representing and Locating Materials (cont’d.)

• Locating materials with dimensions (cont’d.)– Vertical dimensions

• Given from bottom of sole plate to top of the top plate for wood-frame structures

• Steel stud walls• Structural steel• Masonry units• Concrete slab

Representing and Locating Materials (cont’d.)

• Locating materials with dimensions (cont’d.)– Horizontal dimensions

• Use varies greatly• Usually not placed on partial sections or details,

except for footing widths• Generally are located from grid lines to desired

member

Representing and Locating Materials (cont’d.)

• Drawing symbols– Symbols found on sections include:

• Grid markers• Elevation markers• Section markers• Detail markers• Room names and numbers

Representing and Locating Materials (cont’d.)

• Drawing notations– Used to specify materials and explain special

installation procedures• Placed as either local or keyed notes• When possible, notes should be placed on exterior

of the building• Smaller the scale, more generic the notes