Ch 8 Reading Roofs Flashcards
A large space that is created by a steep pitched roof (arched, gable, etc.) for drainage, and or appearance
Attic
Known as framing junctions, where two or more structural members are joined, and how they are joined
Component connections
This type of construction is solid lumber of 2 x 6” or larger used in standard framing configuration
Conventional construction (often referred to as stick frame)
Defined as a small space that is created when roof is raised above the level of ceiling, joists and rafters to provide a pitch for drainage
Cockloft
The weight of the building itself, and anything permanently attached to the building
Dead load
A series of 1 x 6 in. boards that run at a 45° angle from the exterior walls to the primary structural members and provide increased structural stability as they cross more roof structural members
Diagonal sheathing
Wood products made from a composite of glue veneers layers and/or wood chips that are pressed together to form components that replace sawn lumber sheathing and other structural materials
Engineered wood
Roof rafter used in hips or valleys to span between ridge boards or wall plates
- Jack rafter
Jack says valley
Valley says roof
Solid or engineered products used to form assembly-built structural elements that are lower in mass than previous construction method
Lightweight construction
Trusses that are compromised of members of less than 2” x 4” or smaller and are often made from engineered lumber or metal
Lightweight trusses
Any load applied to a building other than dead loads. These are typically transient moving, impacting or static (like furniture). Examples include peoples snow and wind. Not a permanent part of a structure.
Live load
This refers to the degree of slope or pitch for a roof and is expressed as a ratio for example a 4:12 pitch means that the roof rises 4 inches vertically for 12 inches of horizontal distance
Roof slope/pitch
All manner of material used to cover or in case, walls, ceilings, and roofs of frame structures. For a roof it is the first layer of covering.
Sheathing
A series of 1 x 6 inch boards that run at a 90° angle to support structural members.
Straight sheathing
Large dimension lumber used to form a truss. Commonly found an older roof. This type of construction is normally made from full dimension lumber and is often comprised of multiple members bolted together to form one structural member.
Timber truss
An engineered structural element that uses groups of rigid triangles to distribute and transfer loads. The triangles create an open webspace. These are used in lieu of solid beams, and many buildings. A triangle is the simplest geometric figure that will not change shape when the sides are fixed.
Truss
An attic space created by the open web nature of trusses
Truss loft
The eight most common roof styles in the United States
- Gable
- Hip (pyramid)
- Gambrel
- Monitor
- Sawtooth
- Flat
- Bridge truss
- Arched
Perhaps the most popular style of roof in the United States as there are literally millions of residential single-family occupies with the simple to construct and attractive roof
Gable
This term is derived from an A-frame configuration: two sloped or angled surfaces between two flat ends
Gable roof
For a gable roof these are the two most common methods of construction
- Conventional (stick frame)
- Lightweight or truss construction
A horizontal beam connecting to opposing rafters in the top third of the A shape
Collar beams
(Not top beam but top third)
Common metal gusset plate connector size
18 gauge steel plates with prongs of 3/8 inch penetration
Considering glue truss applications, the glue in the finger joint configuration has been indicated will soften at approximately ____ to ____ temperature
350 to 400 F
In conventional construction, a ridge board and rafter of 2 x 6” or larger with nails can last approximately ____ times longer than 2 x 4” trusses when exposed to fire
- 4
(Conversely, 2x3/2x4 with gussets = early failure - one-fourth the time)
This roof is nothing more than a flat roof that has been constructed with a pitch that exceeds what degree
- Shed
- 10°
Concerning a shed roof, a LOW pitch is defined as a ____ to ____ degree angle
10 to 20° angle
Most shed roofs are constructed with a pitch exceeding _____ degrees
20
A true flat roof has a pitch angle between ___ and _____ with a minimum of ___ degrees recommended for drainage
- 0 and 10°
- 6°
I-joists consist of three main components
- Top chord
- bottom chord
- stem or closed web
This truss is the most common type of lightweight truss, and it is a favorite method of roof construction for both residential and commercial structures, large and small across this country
Flat roof with metal gusset plate construction or glue
This older arched roof is not considered a true truss roof is definitely one of the most unique due to its method of construction and the amount of lumber that was utilized for its construction
A lamella roof (also known as a Summerbell roof)
Although lamella roofs can offer some protection when exposed to fire, total roof collapse may occur if fire removes more than _____ % of the roof structure
20%
Concerning a tied arch roof, horizontal metal tie rods are used to ____ while vertical tension rods are used for ____
(Horizontal) - counter lateral forces that the arch top beam places on walls
(Vertical) - hang from the arch top beam to add tension to the bottom tie-rod or to support ceiling utility needs
Concerning arched roofs, the tied arch roof when it fails ____, whereas the arch truss and bowstring roof _____
- Tied arch - failure of any part can precipitate total failure
- Arch truss/bowstring truss - fails in sections
A _____ roof is normally identified by its larger humped shape as well as diamond or honeycomb grid appearance
Lamella
Vertical ventilation on a _____ roof should only be attempted from an aerial device
Lamella
The _____ chord of rigid arch truss transfers loads to a wall, whereas the _____ chord serves that purpose for bowstring trusses
- Bottom
- Top
Fire ground experience indicates that timber truss roofs (except the tied arch) can last ____ minutes under heavy fire conditions
Over 30
Types of roofs with strong areas somewhere other that over outside bearing walls
Gable (ridge and valleys)
Hip (ridge pole, valley rafters, hip rafters)
Sawtooth (near glass panels)
Corrugated roofs (the ridge)
Clay tiles can reduce the interior temperature of a structure by _____ to ____ degrees Fahrenheit
5 to 10°
Corrugated steel (roofing) thickness is ______ to _____ VERSUS metal roofing thickness _____ to _____
- 18 to 20 gauge
- 22 to 26 gauge
A _____ is the junction of a vertical member (such as as a skylight riser, parapet wall, etc.) and a horizontal member (such as a roof) where the intersection junction is covered by a roofing material
Cricket
The joints of trusses were they are connected are referred to as?
Nodes
______ are used where two roof lines join
- Valley rafters
Jack says valley
Valley says roof
This roof is often characterized by dormer windows that protrude from the steep slopes of the lower pitches
- Mansard roof
(bridge truss = fails in sections, EASILY identifiable from the street)
(Mansard with dormer = bridge truss)
In this type of construction, the roof uses 2x3 or 2x4 rafters spaced up to 36” on center and butted together at the ridge without a ridge board and typically use 1x4 in spaced sheathing
Bungalow Construction
The presence of 2x4 in rafter tails under the eaves is an excellent indicator of what?
Lightweight Construction
This type of roof is supported by these three methods?
- Arches terminate on a foundation on the ground
- Roof supported by exterior wall that are supported by exterior buttresses
- in FEW instances, internal tie-rods with turnbuckles
Lamella (Summerbell)
The primary hazard of the tied arch is the?
Early failure of the metal tie-rods and turnbuckles
An architectural structure or appliance designed to contain a fire for heating or cooking
Fireplace
A structural component used for the venting of a hot flue gases or smoke from a stove, boiler, furnace, fireplace or other appliance
Chimney
3 types of ventilators
- Capped top
- Eyebrow-type top
- Familiar turbine
Skylights in the middle portion of a roof in habitation occupancies indicate what type of configuration?
Center hallway (Type I)
This type of truss roofs are easily identifiable from the street due to their sloping sides and flat top
Bridge truss roof
One of the first indicators of this type of roof is roof ventilation personnel opening a roof and finding an abnormally large attic when one should not be present
Rain roof
This type of roof will ALWAYS have a cockloft and necessitates evaluating for the presence of fire
Inverted roofs
- This appendage is not real masonry, but a pre-fabricated fireplace appliance that can be installed almost directly against combustible services
- The primary hazard is typical lack of fire, stopping in the vertical
- Can be considered a modern version of balloon frame construction
Zero clearance fireplace
Fireplaces that are constructed in the interior of a structure can offer two substantial size-up considerations
- personnel on the ridge of a roof
- older construction and unreinforced
masonry
Metal roofing has become more fashionable in recent years with the most popular style generally referred to as:
Standing seam steel roofing
