Roof Sailing Roof Ventilation Systems 1 — Questions and Answers
Question 1: What is the primary purpose of proper attic ventilation in a roofing system?
- To reduce the weight of the roof
- To regulate temperature and moisture levels in the attic (Correct answer)
- To improve the appearance of the roofline
- To increase solar panel efficiency
Correct answer: To regulate temperature and moisture levels in the attic
Proper attic ventilation maintains temperature and moisture balance, preventing heat buildup in summer and condensation/ice dams in winter.
Question 2: According to FHA and most building codes, what is the minimum net free ventilation area (NFVA) required per square foot of attic floor?
- 1/100
- 1/150 (Correct answer)
- 1/300
- 1/600
Correct answer: 1/150
Building codes generally require 1 square foot of NFVA per 150 square feet of attic floor without a vapor barrier, or 1:300 with a vapor barrier.
Question 3: In a balanced ventilation system, intake vents are located where on the roof assembly?
- At or near the ridge
- At the soffit or eaves (Correct answer)
- In the gable ends only
- Just below the ridge
Correct answer: At the soffit or eaves
In a balanced system, intake (low) vents are located at the soffit/eave and exhaust (high) vents are near the ridge to leverage natural air convection.
Question 4: Which type of roof vent is installed at the peak of the roof and runs continuously along the ridge?
- Turbine vent
- Power attic vent
- Ridge vent (Correct answer)
- Soffit vent
Correct answer: Ridge vent
A ridge vent is installed along the full length of the roof peak, allowing warm moist air to exhaust evenly across the entire attic.
Question 5: What problem can occur when a power attic ventilator (PAV) is installed without adequate intake ventilation?
- Roof deck delamination
- The PAV draws conditioned air from the living space, increasing energy costs (Correct answer)
- Ice dam formation
- Shingle granule loss
Correct answer: The PAV draws conditioned air from the living space, increasing energy costs
Without sufficient intake vents, a PAV creates negative pressure and pulls conditioned air from the house through gaps, significantly increasing energy bills.
Question 6: Which condition is a direct result of insufficient attic ventilation during winter months?
- Premature shingle cracking
- Ice dam formation at the eaves (Correct answer)
- Sagging roof deck
- Accelerated granule loss
Correct answer: Ice dam formation at the eaves
Poor attic ventilation allows heat to build up, melting snow that refreezes at cold eaves to form ice dams, which can cause water to back up under shingles.
Roof Sailing Roof Ventilation Systems 1
What is the primary purpose of proper attic ventilation in a roofing system?