Chapter 20

Roof Plan Components

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Links for Chapter 20

Roof Plan Types

Roof Shape

Roof Materials

Related Web Sites

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Roof Plan Types• Roof plan is used to show the shape of the

roof including roofing material, vent, and underlayment

• Size and direction of construction members are drawn

• Required for only complex roof designs

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Roof Pitch• Slope or roof pitch is the description of the

angle of the roof as horizontal run and vertical rise

• Pitch is represented with a fraction which converts to an angle

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Roof Shape• Flat Roof

– Economical– Built with slight pitch so water can run off– Parapet (false wall) is built around the roof

3 LAYER BUILT-UP ROOFING MATERIALHOT MOP BETWEEN EA. COURSE.

1/2" PLY ROOF SHEATHING

RAFTERS / CEIL. JST @ 12", 16" OR

10" BATT INSULATIONR-30 MIN W/ 2" AIRSPACE ABOVE

SOLID BLOCK W/(3)-1" DIA SCREENEDHOLES FOR AIR FLOW

SOLID BLOCKFASCIA

EXTRA PLATE TOPROVIDE SLOPE TO ROOF.

METAL GRAVEL STOP

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Roof Shape• Shed Roof

– Less drainage problems compared to flat roof

– Can be built at any pitch

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Roof Shape

• Gable Roof– Two shed roofs

meet at a ridge– Two or more

gables meet to form a hip or valley

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Roof Shape• A-Frame Roof

– Rafters are used as supporting walls

– The structure appears to form the letter “A”

8 x 14 RIDGE BEAM

6 x 10 FLOOR

DECKING

6 x 12 EXPOSED BEAMS

1" ROOF DECKING

2 x 6 STUDS @ 16" O.C.3/4" FLOOR DECKING

2 x 10 FLOOR JOIST @ 16" O.C.

STANDARD 1 STORY 'T' FOOTING

CONCRETE FOOTING

@ 32" O.C.

BEAMS @ 32" O.C.

2" T.G. FLOOR

A-Frame Roof

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Roof Shape• Gambrel Roof

– Traditional shape from colonial period

– Upper roof is greater pitch than lower roof

– Reduces cost of siding

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Roof Shape• Hip Roof

– Eliminates roof mass– Structure appears

smaller– Two hips form a valley

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Roof Shape

• Dutch Hip Roof– Combination of hip

and gable roof– Center is similar to

a gable roof– Ends are similar to

a hip roof

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Roof Shape

• Mansard Roof– Similar to a

gambrel but angled lower roof is on all four sides

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Roof Shape• Dormers

– Opening in a roof to allow for a window

– Used in gable or hip roof

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Foundation & ½ Wall Section

Brick wall = 9” width( Total exterior wall)

Stucco= 4” ( total exterior wall width)

Block= 8” width ( exterior wall)

Roof SlopeFlat Roof: 2/12 Low Slope: 2/12-4/12 Conventional Slope Roof: 4/12-9/12 Steep Slope: 9/12 and higher

http://www.pole-barn.info/roof-pitch.html

Pitch= Rise/ Clear Span

Slope (pitch)= Rise : RunExample: 5:12Pitch = Rise

___________ Span= 5/24

Roof Pitchhttp://www.pole-barn.info/roof-pitch.html

Command: Line<45 & Dimension

Building Calculator.. Cool!!

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Roofing Materials• Roof materials depend on the pitch, style,

structure cost, and weather• Squares are used to order roofing materials

– A square covers 100 sq. ft. of surface• Roofing materials also effect the framing

members and foundation

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Built-up Roofing• Used with pitch below 3/12• Felt and asphalt is commonly use for flat or

low-sloped roof• Hot asphalt is spread between the layers of

roofing material

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Shingles• Minimum pitch is 4/12 with 15-lb felt

underlayment• Made of wood, asphalt, or fiberglass• Most shingles are three-tab with a self-

sealing adhesive on the back• Wood shakes are thicker than shingles and

more irregular in shape

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Clay and Cement Tiles• Used on expensive homes where the threat

of fire is extreme• Available in both curved and flat designs• Pitch is usually 2½/12 or greater• Roof will be much heavier with tiles

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Metal Panels• Easy to install and therefore less expensive• Panels are made of 22- or 24-gage metal• Provide good water and fire protection• Available in widths of 18” or 24”• Variety of metals are available including

copper, stainless steel, aluminum and zinc

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Related Web Sites• Asphalt Roofing Manufactures -

www.asphaltroofing.com• Cedar Shake & Shingle Bureau -

www.cedarbureau.org• Roofing Industry Educational Institute-

www.riei.com• Single Ply Roofing Institute- www.spri.com