Ch. 11 Roofs Flashcards
Low slope roofs
Have a slope up to 3/12
*Each 12 units of horizontal dimension, roof slopes upwards 3 units
Medium to High Slope
Have a slope of 4/12 to 12/12
A slope of 12/12 equates to a 45 degree angle
*Some mansions and churches have a slope of 18/12, too steep to work from
Gable Roof
Common roof style consisting of two inclined surfaces meeting at the highest side to form a ‘ridge” (Little House on the Prairie)
Hip Roof
Sloped in four directions w/a degree slope similar to Gabled roof (stand alone garage or normal house roof)
Gambrel Roof
Slope in two directions w/a break in the slope on each side (Barn like roof)
Mansard Roof
Break in the slope of the roof on all four sides. A mansard roof constructed w/a flat deck is sometimes known as a modern mansard or deck roof.
Butterfly Roof
Slopes in two directions - basically two shed roofs meeting at their lowest eaves
Monitor Roof
Designed to provide light and ventilation; once common in factories; openable windows on the vertical sides are known as “clerestories”
Sawtooth Roof
Commonly used on industrial buildings for light and ventilation; glass sections should face North for best amount of light
*Modern ventilation and lighting systems have eliminated the need for monitor and sawtooth roofs
The most common roof types …
… constructed w/conventional framing:
- Shed
- Gable
- Hip
- Gambrel
- Mansard
Common Truss
Arranged w/all the chords and diagonal members in the same plane
Flink and Pratt trusses
Most common types used for pitched roofs
Materials used in Arches
- Masonry
- Laminated Wood
- Steel
Roof Deck Materials
- Plywood
- Wood Plank
- Corrugated Steel
- Precast Gympsum or Concrete Planks
- Poured Gympsum
- Poured Concrete
- Cement Planks containing Wood Fiber
Roofing Materials must resist …
- Punctures from hail
- Corrosion from fog, salt air, smoke, and other pollutants
- Expansion and contraction from rooftop temps that can range from over 100 degrees in summer and below 0 degrees in winter
Vapor barriers …
… are designed to reduce the diffusion of interior moisture into the insulation layer; consist of continuous sheet of material including:
- Plastic
- Aluminum foil
- Kraft paper laminated w/asphalt
- Asphalt saturated roofing felt
Fluid Applied Membranes
Useful w/curved roofs; applied as a liquid and allowed to cure using:
- Neoprene
- Silicone
- Polyurethane
- Butyl rubber
Shingles
Thin, tapered slabs of wood that are sawn from pieces of a tree trunk
Shakes
Manually or machine split from wood and thicker then shingles. Usually from red cedar, white cedar, or redwood
Class A Roof Covering
Effective against a severe fire exposure
Class B Roof Covering
Effective against a moderate fire exposure
Class C Roof Covering
Effective against light fire exposure
Vegetative Roofs
Also known as Green Roof can vary from 20 lbs per square foot to 150 lbs per square foot
