Blueprint Reading & Layout Flashcards

What is the purpose of a north arrow on a site plan?

Answer: To orient the drawing to compass directions for proper sun, wind, and zoning analysis

The north arrow orients the drawing to true or magnetic north, allowing planners, builders, and owners to understand solar exposure, shadows, prevailing winds, and the relationship of the building to the lot and street.

A structural drawing shows a footing with dimensions '600×300 mm'. Which dimension is width and which is depth?

Answer: 600 mm wide × 300 mm deep

Standard Canadian drafting convention for footings lists width first and depth second: 600 mm wide × 300 mm deep. Width is the horizontal dimension; depth is vertical (into the ground).

What does the abbreviation 'FFL' mean on a construction drawing?

Answer: Finished Floor Level

FFL stands for Finished Floor Level — the elevation of the completed floor surface including all finishes (tile, hardwood, etc.). It differs from the structural floor level by the thickness of floor finishes.

On electrical drawings included in a construction set, what symbol typically represents a duplex outlet?

Answer: A circle with two horizontal lines

A duplex receptacle (standard outlet) is conventionally shown as a circle with two short parallel horizontal lines extending from it, resembling the two slots of the outlet. Symbols follow CEC/drawing legend conventions.

What does a phantom line (long dash, short dash, short dash pattern) indicate on a drawing?

Answer: An alternate position, future work, or repeated features

Phantom lines show alternate positions of moving parts, future or proposed work, repeated detail, or items from adjacent drawings shown for reference. They are distinct from centre lines (long-short pattern) and hidden lines (all short dashes).

When checking a floor plan for total square footage, a carpenter must account for wall thickness. A room shown as 4 800×3 600 mm to the face of framing with 140 mm walls on all sides has what interior clear dimension?

Answer: 4 520×3 320 mm

With 140 mm walls on each side, subtract 280 mm from each dimension: 4800-280=4520 mm and 3600-280=3320 mm. The interior clear dimensions are 4520×3320 mm.