Mixed Deck — All 403A Topics Flashcards

What is the purpose of a story pole when laying out a building?

Answer: To transfer consistent vertical measurements to multiple locations

A story pole (or storey rod) is a long straight board marked with all vertical heights — floor-to-floor, window heights, door heights — used to quickly transfer identical measurements to walls, frames, and openings throughout the building.

An 'open stringer' (cut stringer or sawtooth stringer) is characterized by:

Answer: Notches cut along the top edge create a sawtooth profile to support treads and risers

A cut (open) stringer has triangular notches cut from its top edge to form seats for the treads and risers, creating a visible sawtooth profile.

What is the purpose of hurricane ties (rafter ties) connecting rafters to wall plates?

Answer: To resist uplift forces from wind that try to lift the roof off the wall

Hurricane ties (also called rafter ties or H-straps) are metal connectors that anchor rafters directly to the wall framing. They resist uplift forces from wind pressure acting on the underside of roof overhangs and from negative pressure on the roof surface.

What is a roof truss and how does it differ from conventional rafter framing?

Answer: A truss is a prefabricated triangulated framework that spans the full building width without interior bearing walls

A roof truss is a pre-engineered, prefabricated triangulated framework typically made from 2×4 or 2×6 lumber connected with metal connector plates. Unlike conventional rafters that may require interior bearing walls, trusses span the full width of the building.

On a site plan, what do contour lines represent?

Answer: Points of equal elevation on the ground

Contour lines connect points of equal elevation on a site plan, showing the topography and slope of the land. Closely spaced contour lines indicate steep terrain, while widely spaced lines indicate gentle slopes.

What is the difference between a control joint and an expansion joint in a concrete slab?

Answer: Control joints are tooled or sawn to induce cracking at planned locations; expansion joints allow thermal movement between separate concrete sections

Control joints (contraction joints) are weakened planes that cause the concrete to crack at a predetermined location rather than randomly — they do not allow movement. Expansion joints use a compressible filler to allow adjacent slabs to move toward each other without cracking.

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).

Under the National Energy Code of Canada for Buildings, what is the general requirement for the thermal performance of building envelopes?

Answer: The building envelope must meet minimum insulation R-values based on the climate zone

The National Energy Code of Canada for Buildings (NECB) sets minimum insulation requirements (expressed as effective R-values or RSI values) for walls, roofs, and foundations based on the climate zone and heating degree days of the building's location.

When framing a valley on a roof where two roofs of equal pitch intersect, what is the mathematical relationship between the valley rafter length and the common rafter run?

Answer: The valley rafter run equals the common rafter run multiplied by 1.414 (√2)

Like hip rafters, valley rafters run at 45° in plan view. For a regular equal-pitch roof, the valley rafter's horizontal run equals the common rafter run times √2 (1.414). The actual rafter length is then calculated using the slope.

When is it generally safe to strip wall formwork for a standard residential foundation in moderate Canadian temperatures?

Answer: 24 to 48 hours after pouring

Wall formwork can typically be stripped 24 to 48 hours after pouring in moderate temperatures (above 10°C), as the concrete will have gained enough strength to be self-supporting. Cold weather may require longer curing times before stripping.

What is the purpose of form release agent (form oil) applied to formwork before a concrete pour?

Answer: To prevent concrete from bonding to the form so it can be stripped cleanly

Form release agents create a barrier between the concrete and the form surface. Without them, concrete bonds to the form — especially plywood — making stripping difficult and damaging both the concrete surface and the form for reuse.

What is the purpose of reshoring (backshoring) in multi-storey concrete construction?

Answer: To re-support previously stripped floors that haven't reached full design strength

Reshoring involves reinstalling temporary vertical supports under concrete floors that have been stripped of their original formwork but haven't yet achieved full design strength. This distributes construction loads from upper floors to lower levels.

What is the function of a drip edge on a roof?

Answer: To direct water away from the fascia and into the gutter

A drip edge is a metal flashing installed at the eaves and rakes of a roof. It directs water runoff away from the fascia board and into the gutter, preventing water from wicking back under the shingles or rotting the fascia and soffit.

What is the purpose of a waterstop installed at a construction joint in a below-grade concrete wall?

Answer: To prevent water migration through the construction joint from the outside to the inside

Waterstops are strips of PVC, rubber, or metal embedded across construction joints in water-retaining or below-grade structures. They create a physical barrier that water cannot migrate through, sealing the joint against hydrostatic pressure from groundwater.

Using the stair comfort formula 2 × Rise + Run = 635mm, what tread depth is required for a unit rise of 190mm?

Answer: 255mm

2 × 190 + Run = 635mm; 380 + Run = 635; Run = 255mm.

What is the purpose of a let-in brace in wood frame wall construction?

Answer: To provide racking resistance (lateral load resistance) in the wall

A let-in brace is a piece of 19×89 mm (1×4) lumber notched into studs at a 45° angle from top corner to bottom corner. It resists racking forces (lateral loads from wind and seismic) that would otherwise push the wall out of plumb.

How is the total rise of a staircase calculated from a drawing?

Answer: By measuring from finished floor to finished floor vertically

Total rise is the vertical distance from finished floor level at the bottom to finished floor level at the top. This dimension drives all stair calculations — number of risers, individual riser height, and stringer length.

According to the NBC, what is the minimum attic ventilation ratio for a residential roof in Canada?

Answer: 1:300 of the insulated ceiling area

The NBC requires a minimum ventilation ratio of 1:300 of the insulated ceiling area when ventilation is provided at both the soffit and ridge/upper area. If ventilation is only at one level, the ratio increases to 1:150.

What does 'dead load' mean in the context of structural framing?

Answer: The permanent static weight of the building structure and fixed components

Dead load is the permanent, static weight of all building materials — framing, sheathing, insulation, roofing, drywall, flooring, and fixed mechanical equipment. It does not change once construction is complete and must be supported continuously.

What is the purpose of a trimmer stud (jack stud) in a framed wall opening?

Answer: To support the header directly and transfer its load to the bottom plate

Trimmer studs (jack studs) are installed alongside king studs and directly support the header above a door or window opening, transferring the load from the header down to the bottom plate and foundation.