2009 Ibc Roofing Exam

Explanation
A built-up roof covering refers to the process of layering multiple layers of felt together and cementing them to create a durable and waterproof roofing system. This is typically done by alternating layers of bitumen and roofing felt, and then surfacing it with a cap sheet, mineral aggregate, smooth coating, or similar material. This type of roof covering is commonly used in commercial and industrial buildings due to its strength and longevity.

Explanation
The correct answer is "One-third". This means that the total area of penthouses and other rooftop structures should not exceed one-third of the area of the supporting roof. This regulation ensures that the size of these structures does not overpower or overshadow the main roof, maintaining a balanced and aesthetically pleasing architectural design. It also prevents excessive load and stress on the supporting structure, ensuring its stability and safety.

Explanation
A scupper is an opening in a wall or parapet that allows water to drain from a roof. It is designed to prevent water from accumulating on the roof and causing damage. Scuppers are typically found on flat roofs or roofs with a low slope. They provide a pathway for water to flow off the roof and away from the building. Surface drains, on the other hand, are typically used to collect and drain water from paved surfaces such as parking lots or sidewalks. Overflow and horizontal drain are not specific terms for this type of opening in a wall or parapet.

Explanation
It is not permissible to install a new roof covering over two existing layers of roofing material because it can lead to excessive weight on the roof structure and compromise its integrity. Additionally, the underlying layers may have damage or deterioration that could affect the new roof's performance. Removing the existing layers before installing a new roof ensures proper installation and avoids potential issues in the future.

Explanation
The correct answer is 0.019. This is the minimum thickness required for the metal flashing used with asphalt shingles to be corrosion resistant. A thinner metal may not provide sufficient durability and protection against corrosion, which is important for the longevity and performance of the flashing.

Explanation
Liquid applied roofs are a type of roofing system that is installed by applying a liquid coating directly onto the roof surface. To ensure proper drainage and prevent water pooling, these roofs need to have a design slope. The design slope refers to the angle or incline of the roof surface. In this case, the correct answer is "One-fourth," which means that for every 12 units of horizontal distance, the roof should have a vertical rise of one-fourth of that distance. This slope allows water to flow off the roof efficiently and prevents water from accumulating, which could lead to leaks or damage.

Explanation
Scuppers are drainage openings in a building's walls or roof that allow water to flow out. It is important for scuppers to have a sufficient opening dimension to ensure proper drainage. Therefore, the correct answer is 4 inches, as scuppers should not have an opening dimension of less than this size to effectively drain water.

Explanation
When installing a copper metal-sheet-roof-covering system, the minimum application shall be 16 ounces per square foot. This means that for every square foot of roof area, at least 16 ounces of copper metal-sheet-roof-covering system should be applied. This ensures proper coverage and protection for the roof.

Explanation
For open valleys using asphalt shingles, lining them with metal is recommended. The valley lining should be at least 24 inches wide. This width ensures proper water flow and prevents water from seeping through the valley and causing damage to the roof. A wider valley lining also provides better protection against ice dams and debris buildup, prolonging the lifespan of the roof.

Explanation
Class A roof assemblies are those that are effective against severe fire test exposure. This means that they have a high level of fire resistance and can withstand intense heat and flames for a significant amount of time. These roof assemblies provide a strong barrier against fire, helping to protect the building and its occupants from the spread of flames and smoke.

Explanation
The maximum mean roof height of a building with aggregate used on the roof as ballast is 15. This means that the height of the building's roof, when using aggregate as ballast, should not exceed 15 units. The other options (20, 35, and 55) are not the correct maximum mean roof height for this specific scenario.

Explanation
Non-classified roof coverings are allowed on buildings of Group R-3 and Group U occupancies, as long as there is a minimum fire separation distance of 6 feet measured from the leading edge of the roof.

Explanation
The correct answer is 4,2. This means that asphalt shingles should have a minimum of 4 fasteners per strip shingle or 2 fasteners per individual shingle. This ensures that the shingles are securely fastened and will not be easily dislodged or damaged by wind or other external factors. It is important to follow the manufacturer's guidelines to ensure proper installation and performance of the shingles.

Explanation
The minimum overlap for the underlayment on a 3:12 roof is 19 inches. This is because a 3:12 roof means that for every 12 inches of horizontal distance, the roof rises 3 inches vertically. This is a relatively low slope, so a larger overlap is required to ensure proper water resistance and protection against leaks. A 19-inch overlap provides sufficient coverage and helps to prevent water from seeping through the shingles and reaching the underlying structure.