403A Roofing Systems 2

Question 1

What causes ice dams on Canadian roofs and what is the primary prevention method?

Accepted Answer

Heat escaping through the roof melts snow, which refreezes at the eaves; adequate insulation and ventilation prevent them

Answer

Ice dams form when heat escaping from the living space warms the roof deck, melting snow that runs down and refreezes at the cold eaves overhang. The primary prevention is maintaining consistent roof deck temperature through adequate insulation and continuous attic ventilation.

Question 2

What is roof sheathing and what material is most commonly used in Canadian residential construction?

Accepted Answer

Plywood or OSB panels nailed to the rafters or trusses to create the roof deck

Answer

Roof sheathing consists of plywood or OSB (oriented strand board) panels fastened to the rafters or trusses to create a solid roof deck. In Canada, 12.5 mm (1/2 inch) or 15.5 mm (5/8 inch) panels are most common, providing the nailing base for roofing materials.

Question 3

What is the purpose of step flashing where a roof meets a vertical wall?

Accepted Answer

To prevent water from penetrating the joint by directing it over each shingle course

Answer

Step flashing consists of individual L-shaped metal pieces woven into each course of shingles where the roof meets a vertical wall. Each piece laps over the one below, creating a shingled waterproof barrier at the joint.

Question 4

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

Accepted Answer

To direct water away from the fascia and into the gutter

Answer

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.

Question 5

What is a valley in roofing and what are the two main methods of finishing it?

Accepted Answer

A valley is where two roof slopes meet forming a V-channel; finished with open metal valley or closed-cut (woven) shingles

Answer

A roof valley is the internal angle formed where two sloping roof sections meet. The two main finishing methods are open valleys (lined with metal flashing left exposed) and closed-cut or woven valleys (where shingles from both sides are interlaced across the valley line).

Red Seal Carpenter 403A Practice Test

Red Seal Carpenter 403A Practice Test

403A Roofing Systems 2