Roof Ventilation

How to Identify a Failing Roof and Danger Signals | Mastering the Roof by GAF

GAF- Mastering The Roof (chapter 02) Danger signals of a poorly installed roofing system don’t have to appear only on the roof or ceiling. For example, poor attic ventilation can result in excessive moisture which leads to blistering and peeling of exterior paint. A faulty roof structure poses a threat to both the home and its occupants. Water damage, mold, and rot are just a few of the risks associated with a failing roof. In this section we are going to identify a variety of different problems associated with roof damage and defects. Leaking is obviously one of the most common signs of a failing roof system, You often see these signs in an attic after a heavy rain. The leaking may be caused by inadequate underlayment or deteriorated flashing. Another leak indicator is the appearance of stains on interior ceilings and walls. These leaks are often caused by ice damming, which forces water under the shingles at the eaves. Danger signals of a poorly installed roofing system don’t have to appear only on the roof or ceiling. For example, poor attic ventilation can result in excessive moisture which leads to blistering and peeling of exterior paint. Another danger signal associated with poor attic ventilation may be decay of roof shingles, sheathing, or siding due to excess moisture under the roof deck. Discoloration can also indicate a loss of granules due to the age of the shingles, which in turn can result in accelerated aging and ultimate failure. Another danger signal is missing, cracked or curling shingles. Although asphalt shingles give many years of service, they do eventually wear out.

Types of Roof Ventilation

What are Power Vents?

Power Vents are active roof ventilation.

They are a great way of ventilating hip style roofs.

As with any roof ventilation balance between intake and exhaust matters. 


Tha GAF power vents we use include both a thermostat and humidistat, they can turn on and off automatically depending on the current attic temperature and/or attic humidity. These fans draw fresh air in from your vented soffit and sends hot attic air outdoors.

All Master Flow® Roof-Mounted Power Attic Vents are factory-tested
before shipment and include rigid brackets and a heavy-duty insect/
animal screen for maximum performance and protection.

• High Efficiency… PSC (permanent split capacitor) motor uses
less energy than typical competitors’ units*
• Better Looking… Compact size with hemmed dome for
a sleek look
• Available in Popular Colors… To complement your roof shingles
• Adjustable Thermostat… Included on all models
• Optional Adjustable Humidistat/Thermostat… Available on
“HT” models
*Based on GAF testing at 120 volts

What is Ridgevent?

The best overall value in attic ventilation, ridge vents combine a low installed cost with exceptional aesthetics. They ventilate at the most effective location on the roof – the ridge.

Cobra® Ridge Runner® offers the performance of a baffled rigid vent with the ease of installation typically found in a roll ridge vent. It features a shingle-over design to blend into the ridge line.

Available In All Climate.

• Vents the Attic… Allows heat & condensation to escape at
the most effective location — the ridge
• Effective… Cobra® Ridge Runner® provides 12.5 sq. inches
per lineal foot of net free ventilating area
• Weather Fighter™ Filter… Helps prevent all types of
weather infiltration
• Fast & Easy to Install… Fully nail-gunable; simply roll out and
fasten with included 13
/4″ coil nails
• Easy Sizing… EasyTear™ feature allows you to hand-tear product
in 12″ increments — no knives necessary and less waste!
• Fits Better… Extra-flexible hinge allows installation on 3:12 to
16:12 sloped roofs
• Ridge Cap Compatible… Works with 12″ width ridge
cap shingles
• Peace of Mind… Eligible for up to a Lifetime limited warranty
when installed on Lifetime Shingle roofs*

What are Box Vents

Box vents are passive roof vents and work better when used with soffit ventilation.

Gaf premium metal roof louvers, passively help to exhaust heat and moisture from the attic.

• Slant-Back Design for Optimum Performance… An excellent
choice against weather infiltration, especially in steep-slope
• Long-Lasting Construction… Available in aluminum construction
(SSB960A) or galvanized construction (SSB960G)
• 20% More Ventilating Capacity*… A full 60 sq. in. of net free
ventilating area (NFA) per vent
• Optional Weather Filter… helps resist virtually all types of
weather infiltration (available on aluminum model SSB960AWF)
• Lower Installation Costs… Fewer vents needed for installation*
• Easy Installation… Pre-drilled nail holes make installation easier
• Popular Colors Available… to complement most roofs:
Aluminum: Mill, Black, Brown, Weathered Wood, White and
Shingle Match™ Weathered Wood
Aluminum with Weather Filter: Mill, Black, Brown,
Weathered Wood, and White
Galvanized: Black, Brown, and Weathered Wood
Granule-Coated: Black, Brown, Weathered Wood,
and Shakewood

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