roof design. topics of discussions roof types roof construction terms slope vs. pitch roof...
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Roof DesignRoof Design
Topics of DiscussionsTopics of Discussions
• Roof types
• Roof construction terms
• Slope vs. Pitch
• Roof terminology
• Metal framing connectors
• Roof ventilation
Basic ShapesBasic Shapes
• Gable Roof
• Hip Roof
• Flat Roof
• Shed Roof
• Gambrel Roof
• Mansard Roof
• A-Frame Roof
Basic ShapeBasic Shape
• Gable Roof– Slopes in
from two sides
– Gable ends allow for attic venting
Basic ShapeBasic Shape
• Hip Roof– Slopes in
from all four sides
– No gable ends for vent attic
Basic ShapeBasic Shape
• Flat Roof– Requires a
built-up roof
– Slight slope of 1/4” to 12” helps drainage
–
Basic ShapeBasic Shape
• Shed Roof– 3/12 or more
slope– Can be shingled– Economical like
flat roof
Basic ShapeBasic Shape
• Gambrel Roof
– Two slopes from two sides
– Traditional “Barn” shape
– 2nd story under roof
Basic ShapeBasic Shape
• Mansard Roof– Two slopes
from two sides– Top nearly flat– 2nd story
within the roof area
Basic ShapeBasic Shape
• A-frame Roof– Steep for snow
country– Roof and ceiling
same structure
Roof ConstructionRoof Construction
• Basic terms:– slope/pitch--incline of roof
– roof member terms--structure of roof
– eave/cornice--detail showing wall to roof const
– fascia--visible member attached to end of rafters
– ridge--top of roof
– sheathing--material covering the top of rafters
– rafter/ceiling joist--structure framing of roof
– soffit--underneath side of roof overhang
– vents--in soffit, allows air circulation in attic
Slope Vs. PitchSlope Vs. Pitch
• Slope = Rise/Run– expressed as a ratio– always a base of 12– placed on dwg. 12
4
Slope symbol
Text book error (noted as pitch symbol)
•Pitch = Rise/Span• expressed as fraction• reduce to smallest
fraction• not placed on drawing, helpful to carpenter
Roof TermsRoof Terms
• Span– Distance across the building
Roof TermsRoof Terms
• Run– 1/2 the distance across the building (1/2 span
distance)
Roof TermsRoof Terms
• Rise– The distance the roof rises (distance from the
square of house to ridge)
Roof TermsRoof Terms
• Pitch– The fraction of the rise over span
Roof TermsRoof Terms
• Slope– Slope is stated as a ratio of rise over run with
run always as 12
Slope vs Pitch vs AngleSlope vs Pitch vs Angle
• Slope Pitch Angle
• 3:12 1/8 14°0’0”
• 4:12 1/6 18°30’
• 5:12 5/24 22°30’
• 6:12 1/4 26°30’
Roof Member TerminologyRoof Member Terminology
Metal Framing ConnectorsMetal Framing Connectors
•Keeps structural members from separating