Chapter 11 - Roofs Flashcards
Safety points to remember about roofs:
- Roofs are usually not as __________ as floors because they are typically designed to support lighter live loads.
- Many types of roofs construction have inherent ___________ ________ between the ceiling and the roof deck, making it difficult to determine the extent to which fire has developed overhead.
- Over time, _______ may be added to roofs for which they were not originally designed.
- Roofs are subject to wear and deterioration from the ___________.
- strong
- concealed spaces
- loads
- elements
p 304
From a fire fighting standpoint, the roofs of buildings can be classified into three styles: _______, _________, and _________.
flat, pitched, and curved
p 305
Many flat roofs are provided with a slight _______, typically from front to rear to facilitate drainage.
slope
p 306
Low slope roofs have a slope of up to _____ to _____, meaning for each _____ units of horizontal dimension the roof slopes upward ____ units.
3 to 12 / 12 / 3
p 306
Medium to high slope roofs have slopes of ___/___ to ___/___
4/12 to 12/12
p 306
A slope of 12/12 equates to a ____ degree angle.
45
p 306
The simplest pitched roof is the ______ roof that slopes in only one direction.
shed
p 306
The _______ roof is a very common roof style that consists of two inclined surfaces that meet at their high side to form a “ridge”.
gable
p 307
- Pitched roof that has no gables. All facets of the roof slope down from the peak to an outside wall.
Hip roof
p 307
- Style of gabled roof on which each side slopes at two different angles; often used on barns and similar structures.
Gambrel Roof
p 307
- Roof style with characteristics similar to both gambrel and hip roofs. This roof has slopes of two different angles and all sides slope down to an outside wall.
Mansard Roof
p 307
- V-shaped roof style resembling two opposing shed roofs joined along their lower edges.
Butterfly roof
p 307
- Roof style similar to an exaggerated lantern roof having a raised section along the ridge line, providing additional natural light and ventilation.
Monitor Roof
p 308
- Roof style characterized by a series of alternating vertical walls and sloping roofs that resembles the teeth of a saw. This type of roof is most often found on older industrial buildings to provide light and ventilation.
Sawtooth roof
p 308
Curved roofs are most frequently supported by _______ and ___________ trusses.
arches / bowstring
p 308
- A special type of arch constructed of short pieces of wood called lamellas
Lamella arch
p 309
Lamellas vary from ___x___ inches to ___x___ inches and in lengths varying from ____ to ____ feet.
2x8 / 3x16 / 8 to 14
p 309
A __________ dome is created using spherical triangulation.
geodesic
p 310
A ___________ is frequently provided in buildings with pitched roofs to increase the usable space in an attic by increasing the light and ventilation.
dormer
p 310
With the _________ roof, the main joists are located at the level of the ceiling and a framework is constructed above the main joists to support the roof deck.
inverted
p 313
_________ are the inclined joists used to support some types of pitched roofs.
Rafters
p 313
Raftered roof:
The outward thrust of the rafters is resisted by ceiling or attic ______ _______ or collar beams that are in tension.
floor joists
p 314
Wood rafters vary in size from ___x___ inches to ___x____ inches. They can be spaced from ____ to ____ inches apart, depending on the span and design load.
2x4 / 2x14 / 12 to 24
p 314
_________ are a very common roof support system. ________ use less material and are lighter than a comparable beam or joist for an equal span.
Trusses / Trusses
p 314
All the chords and diagonal members lie in the same plane in a ____________ truss.
monoplane
p 315
- Lightweight truss design noted by the bow shape, or curve, of the top chord.
Bowstring Truss
p 317
The ______ of a roof is the portion of roof construction to which the roof covering or “roofing” is applied.
deck
p 317
Roof deck matreials:
Wood panel decking may have a thickness of ____ inch on supports ____ inches on center.
1/2 / 24
p 318
Roof deck materials:
Wood planks will have a minimum ___-inch nominal thickness.
1
p 318
Roof deck materials:
Corrugated steel used in roof decking ranges from ____ gauge, the thinnest, to ____ gauge, the thickest. The overall depth varies from ____ to ____ inches.
29 / 12 3/4 / 2
p 318
Roof deck materials:
________ has the advantage of being “nailable” which means it is possible to nail into the material. _________ concrete can also be made nailable by choosing an appropriate aggregate. ______-___-______ concrete decks are not nailable.
Gypsum / Precast / Cast-in-place
p 318
Roof deck materials:
If a multistory building is to have a flat roof, the usual practice is to use the same ___________ _________ for the roof and the floors because it is more economical.
structural system
p 319
The roof _________ provides the water resistant barrier for the roof system.
covering
p 319
- Final outside cover that is placed on top of a roof deck assembly.
Roof covering
p 320
Flat roof coverings:
Because flat roofs drain more slowly that pitched roofs they usually require more __________ roof covering assemblies than pitched roofs.
complex
p 320
The ________ _________ is designed to reduce the diffusion of interior moisture into the insulation layer. It is needed when the average outdoor temperature is below ____F and the indoor relative temperature is ____ percent or greater at ____F.
vapor barrier / 40 / 45 / 58
p 320
The ____________ of a roof consists of waterproof material that keeps out rain and snow from the interior of the building.
membrane
p 320
The three general categories of membranes ______-____ roof membranes, _______-____ membranes, and ______-_______ membranes.
built-up / single-ply / fluid-applied
p 321
_______-____ membranes use several overlapping layers of roofing felt saturated with a bituminous material that may be either tar or asphalt.
Built-up
p 321
Built up membranes:
The layers of roofing felt are cemented together with a hot ___________ roofing cement.
bituminous
p 321
Built up membrane:
The roofing felt usually is supplied in rolls ___ feet wide. The number of layers of roofing felt used varies, but _____ layers is a common design.
3 / four
p 321
Built up roofs usually last for ____ years if the manufacturers specifications are followed.
20
p 321
A ______-____ membrane roof consists of a single membrane laid in sheets on the roof deck. The membrane material comes in sheets ____ or ____ feet wide and up to ______ feet long. The membranes are very thin, typically ____ to ____ inches thick.
single-ply / 10 or 20 / 200 / 0.03 to 0.10
p 321
The _______-________ membranes are useful for buildings with curved roof surfaces such as domes that would be difficult to cover with other materials.
fluid-applied
p 322
- External covering on a roof that protects the roof from mechanical abrasion. The typical tar and gravel roof uses gravel for this purpose.
Wear course
p 322
The wear course protects the roof from ___________ __________.
mechanical abrasion
p 322
Roof coverings used on pitched roofs are generally one of two broad categories - _______ or ______ roofs and ________ roofs.
shingle or tile / metal
p 323
Wood ________ are thin, tapered slabs of wood that are sawn from pieces of a tree trunk. _______ are split from the wood either by hand or by machine and are thicker.
shingles / shakes
p 324
Wood shingles and shakes used in North America are made for red ______, white _______, or __________ because of the resistance of these woods to decay.
cedar / cedar / redwood
p 324
Asphalt shingles are available in several sizes but the most common size is ____ X ____ inches.
12x36
p 324
Pitched roof coverings:
Slate is a very durable material and can have a life expectancy of _____ years. Slate is also a heavy material, weighting ____ to ____ pounds per square foot.
150 / 8 to 36
p 324
Pitched roof materials:
______ tile is an ancient material known to have been used for thousands of years. The curved ______ tiles are known as “_________” tiles and are used to create imitation (or genuine) __________-style architecture.
Clay / clay / mission / Spanish
p 324
Pitched roof coverings:
________ tiles are made from Portland cement, aggregate, and water. A major advantage of these tiles over wood tiles is their greater ___________.
Concrete / longevity
p 324
Shingles and tiles are usually attached to the roof with _________-__________ nails.
corrosion-resistant
p 325
Asphalt shingles are usually installed over an ___________, which is a layer of roofing felt or synthetic covering.
underlayment
p 325
Slate tiles are provided with ____________ nail holes. The proper installation technique is to have the head of the nail just touching the slate so that the slate is actually __________ from the nail.
pre punched / hanging
p 325
Asphalt shingles are fundamentally ___________. They tend to drip and run under fire conditions and produce a characteristic heavy ________ smoke.
combustible / black
p 325
Clay, slate, and cement tiles are ____________ and produce _____-__________ roof coverings that have excellent resistance to flying brands.
Noncombustible / fire-resistant
p 326
_____________ roofing sheets are generally strong enough to be installed without decking. In these cases the roofing sheets are supported by roof beams or _________. The spacing between the purlins can be from ___ to ___ feet.
Corrugated / purlins / 2 to 6
p 327
The fire hazards of roof coverings are evaluated by test procedures contained in NFPA ______, also designated ASTM ______.
256 / E 108
p 328
Fire ratings of roof coverings:
- Class A roof coverings are effective against a ________ fire exposure
- Class B roof coverings are effective against a __________ fire exposure
- Class C roof coverings are effective against a _______ fire exposure
- severe
- moderate
- light
p 328
- A second roof constructed over an existing roof.
Rain roof
p 329
Green roofs:
Probably the greatest benefit of green roofs is the increase in air quality due to the _________-_______ ________ exchange of growing plants, particularly in urban areas.
oxygen-carbon dioxide
p 329
Green roofs:
The layer of earth required for a rooftop garden can vary from a ____ inches to ___ or ___ feet. Depending on the depth of the soil, the dead load can vary from _____ pounds per square foot to _____ pounds per square foot.
few / 1 or 2 / 20 / 150
p 330
A _____________ system produces clean and reliable energy that can be used in a wide range of applications. ____________ cells in panels can be laid on top of a roof or embedded in the roof.
photovoltaic / photovoltaic
p 330
Photovoltaic roofs:
Even if power to the building is shut off, the panels retain a significant amount of ____________. It is not safe to break photovoltaic cells or skylights that are actually ________ powered.
electricity / solar
p 330
_____-___________ roof structures are often used in sports arenas and at college and universities. A typical use with this type of structure would be a sports practice facility.
Air-supported
p 331
- Structure on the roof of a building that may be used as a living space, to enclose mechanical equipment, or to provide roof access from an interior stairway.
Penthouse
p 331
- Any of a variety of roof structures or devices intended to increase the natural illumination within buildings in rooms or over stairways and other vertical shafts that extend to the roof.
Skylights
p 332
