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Explore different roof types for cabins in Sacramento City College's Cabin Design Project. Learn about gable, hip, flat, shed, and more roof styles. Understand rafters and frame roof construction. Discover terminology for calculating rafter dimensions.
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Weekend Cabin Retreat ProjectRoofs Sacramento City College EDT 300 Kenneth Fitzpatrick, P.E. EDT 300 - Cabin Design Project - Roofs
Types of Roofs • The appearance of a house is affected greatly by the roof lines and material. • The roof should compliment the structure. EDT 300 - Cabin Design Project - Roofs
Gable Roof • The gable roof is very popular. • Easy to build. • Sheds water well. • Provides for ventilation. • Can be used on a variety of house designs. EDT 300 - Cabin Design Project - Roofs
Hip Roof • The hip roof is slightly more difficult to build than a gable roof. • The hip roof is a very popular choice. • Doesnotprovide for ventilation as well as gable roof. • Increased chance of leaks because of hips and valleys. EDT 300 - Cabin Design Project - Roofs
Flat Roof • The flat roof is the most economical roof to construct. • Doesn’t add much to the appearance of the house. • Requires “built-up” or membrane roof covering instead of conventional shingles. • A built-up roof consists of layers of roofing felt and tar. • Usually pitched about 1/8” to 1/2” to provide for drainage. EDT 300 - Cabin Design Project - Roofs
Flat Roof • The flat roof is popular in warmer areas of the country where wide overhangs are desirable for shade and where little or no snow falls. EDT 300 - Cabin Design Project - Roofs
Shed Roof • The shed roof is similar to flat roof but has more pitch. • Frequently used for additions to existing buildings. • A built-up roof is often required. • Pitch must be 3:12 to use shingles. EDT 300 - Cabin Design Project - Roofs
Butterfly Roof • The butterfly roof has not been used widely in the past. • Provides plenty of light and ventilation. • Drainage is the problem. • Flashings must extend far up the roof to prevent leaks. EDT 300 - Cabin Design Project - Roofs
Gambrel Roof • The gambrel roof is sometimes called a “barn roof”. • It has been used extensively for barns. • Provides the additional headroom required for the “Dutch colonial” building style. EDT 300 - Cabin Design Project - Roofs
Winged Gable • The winged gable is a variation on the gable roof. • Ridge peaks are extended to form a point. EDT 300 - Cabin Design Project - Roofs
Dutch Hip • The dutch hip is a combinedgable and hip configuration. EDT 300 - Cabin Design Project - Roofs
Mansard Roof • The mansard roof has not been popular for several years. • Is returning to popularity. • Is a French design. • Is more difficult to construct than hip or gable. EDT 300 - Cabin Design Project - Roofs
A-Frame Roof • The A-frame is a combinedwall and roof. • Originally used for cottages. • Now is used for homes, churches, and other structures. EDT 300 - Cabin Design Project - Roofs
Curved Plate Roof • Similar to Folded Plate roof. • Limited residential application. • Some use in prefabricated modules. EDT 300 - Cabin Design Project - Roofs
Folded Plate Roof • The Folded Plate Roof is a contemporary design. • It is finding some limited application in residential construction. • Quite popular for motels and small commercial buildings. • Many modular, prefabricated units have this type of roof. EDT 300 - Cabin Design Project - Roofs
Traditional Frame Roof Construction EDT 300 - Cabin Design Project - Roofs
Rafters • Roof covering material is supported by roof framing. • The framing must be strong and rigid. • Roof framing consists of several distinct structural elements. • The first and most basic of these elements is the rafter. EDT 300 - Cabin Design Project - Roofs
Rafters • Common rafters are perpendicular to the top wall plate. • They extend from the plate or beyond to the ridge of the roof. • Note that several types of rafters other than common rafters are identified. EDT 300 - Cabin Design Project - Roofs
Rafters • Rafters are cut to the proper dimensions by locating the ridge cut, seat cut, plumb cuts, and tail cut. • The precise layout of these cuts is determined by • The slope or pitch of the roof. • The inside width or clear span of the building. EDT 300 - Cabin Design Project - Roofs
Rafters • Terms that must be understood before calculating rafter dimensions and roof pitch are: • Rise. • Run. • Span. EDT 300 - Cabin Design Project - Roofs
Terminology • Rise - the vertical distance measured from the top of the wall plate to the underside of the rafters. EDT 300 - Cabin Design Project - Roofs
Terminology • Run - one-half of the distance of the clear span. EDT 300 - Cabin Design Project - Roofs
Terminology • Clear Span - is the horizontal distance from the inside of one stud wall to the inside of the opposite stud wall. EDT 300 - Cabin Design Project - Roofs
Roof Slope • Roof slope may be indicated on the drawings by: • A slope ratio diagram • A fractional pitch indicator • An angular dimension. • The angular dimension method is seldomused • It is difficult to measure as accurately as either of the other methods. EDT 300 - Cabin Design Project - Roofs
Roof Slope • When designing a roof, use a standard roof pitch. • 3 in 12. • 4 in 12. • 5 in 12. • 6 in 12. EDT 300 - Cabin Design Project - Roofs
Rafters • Select rafters based on • The distance to be spanned. • The spacing of the rafters. • The weight to be supported. • Rafters for low-slope roofs may also serve as ceiling joists. EDT 300 - Cabin Design Project - Roofs
Roof Weights Per Square Foot • A “light roof” is one that weighs less than 4 lbs per square foot. • Examples: • Cedar shake roof. • Composition roof. • Metal roof. EDT 300 - Cabin Design Project - Roofs
Roof Weights Per Square Foot • A “heavy roof” is one that weighs more than than 4 lbs per square foot. • Examples • Slate. • Clay tile. • Concrete tile. EDT 300 - Cabin Design Project - Roofs