Features of Drawings

Orthographic projection – An orthographic drawing is a two-dimensional view showing a side of an object viewed directly at 90°. Orthographic drawings are flat views so they don’t show any depth. When viewing a drawing of a house each elevation is shown in a separate orthographic view.

Types of Lines

Scales

Scales are proportional representations between the blueprint and the actual construction. Throughout a set of blueprints different scales will be used. Smaller features are drawn at a larger scale to provide a clearer view. These are referred to as Details.

Lines used on blueprints will vary in thickness or design to represent different information.

1. Dimension line – indicates the distance that they are dimensioning by the measurement next to them.
2. Extension line – used to show the extent of a dimension and are located between the object and the dimension line. Extension lines don’t quite touch the object and are drawn lighter than object lines.
3. Object line – broad solid lines used to indicate the visible portion of an object in this view.
4. Leader – arrows that point to an object from a notation on the print.
5. Break line – used where part of the drawing is omitted or cut off that in reality would continue. Its purpose is to save space for other information on the print.
6. Centre line – used to locate the centre of an object typically a window, door or partition wall.
7. Cutting plane line – show where a section view is taken from and uses arrows to show which direction you are looking at in the section view.
8. Hidden line – used to show important objects that would otherwise not be visible in that view. Common examples include cabinets on a floor plan or footings on a foundation plan.

Symbols

Symbols are used on construction drawings to represent the building materials, objects and convey information. Some materials are represented by one symbol when shown in a plan view such as a floor plan; but the same material shown in a section view is represented by a different symbol. Not all architects/draft persons will use the same symbols. Often a legend is part of the blueprint indicating what each symbol represents.

Abbreviations

Abbreviations are used on construction documents to save space.

For further information please review the following:

From the textbook, Carpentry, study the following sections:

• “Types of Lines”
• “Dimensions”
• “Abbreviations”
• “Symbols in Architectural Plans and Building Codes”

For more details, review Instruction sheets on Brightspace.

• BPRT 100 Learning Outcome 1 Learning Step 1,2,3 and 4 (Page 5-16)

• IS 4.2 Symbols

• BPRT 200 Learning Outcome 1 Learning Step 1 (Page 8-15)

• IS 1.2 Symbols

Review in text:

• Understanding Construction Drawings, Chapter 4

Review Questions

1. List and describe the three types of pictorial drawings
2. Match the following statements to the corresponding letter:

1. Plot Plan
2. Foundation plan
3. Floor Plan
4. Framing plan
5. Elevations
6. Section Views
7. Details
8. Schedules

___ Shows a horizontal cut through 4-5 feet above the floor

___ Shows a horizontal cut through the foundation walls

___ Shows support beams and girders

___ Shows information about the lot

___ Shows a skeleton view

___ Shows shapes and finishes of all sides of the exterior of a building

___ Shows small parts drawn at a large scale

___ Used to conserve space on floor plans

___ Shows direction of sloping ground

___ Shows locations of windows and doors

___ Shows direction of footings

___ Shows size, direction, and spacing of framing members

___ Uses symbols with letters or numbers to refer you to the appropriate page

___ Gives detailed information about sizes and types of windows or doors to be installed

3. Floor plans are generally drawn at a scale of _____ (indicate for both metric and imperial).
4. Exterior door symbols are drawn with a line representing the outside edge of the _____.
5. How are ceiling beams represented on floor plans?
6. Exterior dimensions on a wood frame building are taken from the outside face of the _____.
7. In wood frame construction, doors and windows are dimensioned to their _____.
8. Name the following lines

Note: Additional review questions can be found in BPRT 100 Review Exercise 1.2, Review Exercise 2.2, Review Exercise 3.2 and Review Exercise 4.3