11- Building Construction- Roofs Flashcards
Several fundamental safety points regarding roofs include:
-Roofs are usually not as strong as floors (designed to support lighter live loads)
-Many types of roof construction have inherent concealed spaces (between ceiling and roof deck)
-Over time, loads may be added to roofs for which they were not originally designed
From a fire fighting standpoint, the roofs of buildings can be classified into three styles:
Flat, Pitched, Curved
____ Roofs are the easiest roofs on which firefighters can work.
Flat
Low slope roofs have a slope of up to _/12, meaning for each 12 units of horizontal dimension the roof slopes upward _ units.
Medium to high slop roofs have slopes of _/12 to _/12.
Low - 3
Medium to High - 4/12 to 12/12
____ Roofs- Common roof style that consists of two inclined surfaces that meet at their high side to form a “ridge”
Gable
____ Roofs- Style that slopes in four directions and has a degree of slope similar to the gable roof
Hip
____ Roofs- Slope in two directions, but there will be a break in the slope on each side. The space under these roofs can be used as an attic or living space.
Gambrel
____ Roof- Has a break in the slope of the roof on all four sides. Forms a projection beyond the building wall that creates a concealed space through which fire can travel.
Mansard
____ Roof- Roof style that slopes in two directions; basically two shed roods that meet at their low eaves.
Butterfly
____ Roof- Style designed to provide light and ventilation. Once commonly used on factory buildings. A raised central section of the roof extends several feet above the surrounding roof surface. The vertical sides of this section, which are normally openable windows, are known as “clerestories”.
Monitor
____ Roofs- A style once commonly used on industrial buildings for light and ventilation. Ideally, the glass vertical sections should face north because the northern light is more constant during the day and the glare of the sun can be avoided.
Sawtooth
Curved roofs are most frequently supported by ____ and ____ _____.
Arches and Bowstring Trusses
A ______ is frequently provided in buildings with pitched roofs to increase the available living space in an attic.
Dormer
______ Framed Roofs use inclined members to support some types of pitched roofs that are built on site utilizing dimensional lumber.
Conventionally
Conventional roof framing components include:
-Rafters
-Ridge Boards
-Collar Ties
-Ceiling Joists and Rafter Ties
Roof supports are often substantial, with the ridge beam typical one size larger than the rafter. Wood rafters vary in size from _ x _ inches to _ x _ inches.
They can be spaced from __ to __ inches apart.
Vary in size from 2x4” to 2x14”
Spaced from 12 to 24” apart
A _____ truss is arranged with all of the chords and diagonal members in the same plane. This configuration is typical of lightweight trusses.
Common
The joints used in common trusses are often connected using gang-nail type gusset plates. The individual members would be wooden 2x4 or 2x6 and individual trusses would be spaced __ to __ feet apart center to center.
2 to 4’ apart center to center
_____ trusses, which use a curved top chord, use split-ring connectors at all joints, except the heel plates located at the ends of the truss.
Bowstring
Wood panel decking may have a thickness of __ inch on supports __ inches on center.
Thickness of 1/2”
Supports 24” on center
**Wood planks will have a minimum 1” nominal thickness.
Corrugated steel used in roof decking ranges from 29 gauge, the thinnest, to 12 gauge, the thickest. The overall depth varies from __ inches to __ inches.
Varies from 3/4” to 2”
The ____ _____ is designed to reduce the diffusion of interior moisture into the insulation layer. It is used in climates where significant temperature fluctuations are common.
Vapor Barrier
The three general categories of roofing membranes use are:
Built-up membranes
Single-ply membranes
Fluid-applied membranes
Asphalt shingles are available in several sizes but the most common size is __ x __ inches.
12x36”
____ is produced from hard rock that has a tendency to split along one plane. This permits roofing ____ to be produced in smooth sheets as thin as __ inches but it may be as thick as __ inches.
Slate ; Slate
As thin as 1/16” to as thick as 1 1/2”
Roof coverings that pass the required test procedures as classified A, B, or C. The 3 classifications are based on the severity of fire the material can withstand:
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.
Class A- severe
Class B- moderate
Class C- light
A roof is a building’s ___ line of defense against the elemets.
First
A ______ system (solar) produces reliable, clean energy that can be used in a wide range of applications.
Photovoltaic (PV)
A single unit of a solar energy collector is referred to as a “cell.” A series of solar cells arranged in a self-contained unit are referred to as a “panel” or “module.” Individual cells may also be connected in series, as is common with solar shingles. A system of solar panels or shingles is called an “_____.”
Array
The energy feed from PV cells cannot be isolated or shut off. Even when electric power to the building is shut off and the cells are isolated from the building’s electrical system, the cells continue to ___ and ____ electric power. ALL WIRING AND CONDUITS MUST BE ASSUMED TO BE LIVE.
Store and Generate
A rooftop garden constitutes a ___ ___ on the roof structural system, which must be capable of supporting the load.
Dead Load
The primary purpose of skylights is to provide:
Natural lighting to the interior of a building
