Why Roof/attic Ventilation?

• During the summer months, vents allow hot summer air to escape to outside enabling the house to breathe and be more comfortable

• During the winter months, vents help to remove moisture from within the house to eliminated water condensation in the attic

Attic Vent Types• Intake vents

– Under eave ventilators: 1) rectangle/round cornice vents, 2) continuous Soffit vents

• Exhaust vents– Gable end louvers– Roof louvers– Gable end louvers– Ridge line ventilators– Turbine ventilators– Power ventilators

The Way Ventilation Works

Soffit Vent Example

Air

Flow

Venting baffle

INSULATION AREAAIR FLOW

Roof and Attic Ventilation

• Amount of vent area set by code

– IRC

• Vent area = 1/150 x attic area

• Project exampleProject example: attic measures 40’ x 26’ = 1040 sq ft, therefore 1/150 x 1040 = 6.93 sq ft of vent area required for the Soffit and gable end vents

• Usually 50% is intake and 50% is exhaust ventilation ( +/- 3.5 sq ft each type of ventilation)

Sizing Attic Ventilation

• Determine Size of Attic

Multiply width (x) length of attic.

Sizing Attic Ventilation

• Sizing Exhaust Vents

Sizing Attic Ventilation

• Sizing Intake Vents

Vents and Their Shapes

Ventilation Solution

• Project Attic Ventilation:– 2-24”x 30” gable end vents (high

portion of gable)

– 8-16”x 8” soffit vents evenly spaced (4 in each side of cornice)

Handout Material

Elevation Symbols

• Symbols are different than section or plan symbols (see handout)

Surface Materials in Elevation

• Surface symbols for elevations Material symbols are not usually shown in color on working drawings

• Window Representation– Direction of window

movement– Glass symbol

Surface Materials in Elevation

• Attic Vents in gable end

• Wood shingles• Asphalt shingles

• Chimney styles & exterior treatment– (a)stucco– (b)wood– (c)brick– (d)decorative

masonry

Elevation Symbols Example(Complete Treatment)

Elevation Symbols Example(Partial Treatment)

Elevation Symbols Example(Symmetrical Treatment)

Elevation Symbols Example(Cornice Treatments)

Elevation Symbols Example(See Set of

Drawings in Class)

Elevation Example (Computer Generated)

Example of Project Chimney

• Types of Symbols:– Concrete– Rubble Stone– Flashing– Shingles

• Material Callouts• Profile line• Add Dimensions

CONCRETE CAPRUBBLE STONE26 GA GI FLASHING235# COMP SHINGLES

3’-

0”

4” 10”x18” OVAL FLUE

2’-

0”