Fifteen Years of Attic Ventilation Seminars Can Teach You a Lot About Roofing Contractors

Airing by Paul Scelsi it Out

Fifteen Years of Attic Ventilation Seminars can teach you a Lot About Roofing Contractors

arlier this year, Air Vent tions in person. Many times fellow roofers › Left: One commonly asked question roofing wrapped up its 15th season (yes, the competition!) participate in the contractors ask is, “Can more than one type of exhaust vent be used on the same roof above presenting its educational Attic answer. Here are the five most frequently a common attic?” Photo is courtesy of Tim Ventilation: Ask the Expert™ asked questions we continue to hear. Crookston Roofing, Kalamazoo, Mich. Middle: Eseminars. Thanks to the generous participa- 1. Is it possible to have too much attic An attic inspection can identify discoloration on the underside of the roof deck. Photo is courtesy tion of more than 27,000 attendees, the ventilation? It’s possible to have too much of Strander Roofing & Seamless Gutters LLC, program has evolved into a collection of best exhaust ventilation, but you cannot have too Lodi, Wis. Right: Trying to use an exhaust vent practices and things to avoid in residential much intake ventilation. If there is more low on the roof as an intake vent is potentially problematic. There are better ways to achieve and light commercial attic ventilation. After intake ventilation than the attic’s square intake than to incorrectly use an exhaust vent. more than 600 seminars across 44 states and footage requires, it’s not problematic because Photo courtesy of Air Vent Inc. Canada, here’s what we’ve learned about any excess intake converts to “exhaust” on roofing contractors. the leeward side of the house. However, the inefficient airflow movement and weather same is not true when it comes to exhaust. infiltration. They Ask a Lot of Questions If there is more exhaust ventilation than the 2. Can multiple types of exhaust Generally, roofers want to do the job attic’s size requires — and that extra exhaust vents be used on the same roof? It’s not right. And when they are unsure or want to is not balanced with equal intake — it’s recommended. Air follows the path of least confirm their game plan, they ask questions potentially problematic. An exhaust vent resistance. For optimum attic ventilation in an effort to better understand the relation- lacking intake can pull needed intake from purposes, that path is supposed to be from ship between attic airflow, roof geometry, itself (ridge vent) or from a nearby vent low in the attic (intake vents) to the highest climate conditions, vent design, etc. The (from one wind turbine to another; from possible exit point on the roof (exhaust seminar provides a forum to ask those ques- one roof louver to another).This can lead to vents). If two different types of exhaust Airing it Out

vents are combined (ridge vents, power bringing in weather. Furthermore, roof fans, wind turbines, roof-top louvers and louvers placed low on the roof will see gable-mount louvers) the primary path of an increased volume of watershed at an air becomes the distance between the two increased speed from higher points on the types of exhaust vents (for example, the roof compared to their intended position distance between the gable louver and the a few feet from the roof peak. There are a ridge vent). That can short-circuit the attic variety of intake ventilation options avail- ventilation system and lead to inefficient able (rectangular undereaves, continuous airflow and weather infiltration through soffit, vented drip edge, mini-louvers, and › Paul Scelsi has presented seminars on attic ventila- one of the exhaust vents that have sud- roof-top shingle-over edge-of-roof vents) tion since 1998. Photo by Chris King. denly become an intake vent. without having to misuse roof louvers. 3. Is exhaust ventilation without lands more jobs. Many of the re- intake better than zero ventilation? No. The Elite Separate Them- sources and tools that Air Vent offers Both scenarios are potentially problematic. selves From Everyone Else were suggested by roofing professionals. For the exhaust vent to work properly, it By participating in educational And those who use, for example, the must have an equal amount (or more) of seminars, roofing contractors demon- customizable online calculator, the attic intake. That ensures efficient distribution strate their commitment to quality work. ventilation checklist and video clips dem- of airflow inside the attic. Furthermore, However, listening to them explain how onstrating vent performance tell us they without intake, an exhaust vent could they estimate the job, present the plan to increasingly land the job compared to the ingest air/weather from itself or from a the homeowner and then do the actual other contractors. nearby exhaust vent (see Question 1). And work reveals additional strategies that help 5. There’s a time to walk away. if an exhaust vent is ingesting air, it could separate some roofers from others. Here As difficult as it is to walk away from also ingest whatever the air is carrying at are five “difference makers” that caught potential business, roofers tell us they are that moment (rain, snow, debris, etc.). On our attention. ready and willing to do it if the home- the other hand, an attic without ventilation 1. Attic inspections get noticed. owner presses them to do the job counter faces potential troubles associated with heat Conversations with roofing contractors to what the roofer knows is best. And if and moisture buildup as well as ice dams in who routinely inspect attics as part of the the homeowner is unwilling to pay the cold climates. Pick your poison. estimating process have convinced us of roofer’s fair asking price for a balanced 4. What’s the best way to ventilate a this: Generally, homeowners will reward attic ventilation system because another roof with multiple ridge heights above thorough roofers with the project. When bid is significantly lower, roofers tell us a common attic? The basic rule for ridge they are safe and practical, attic inspec- they walk away before compromising heights states that all ridges can be vented tions can make a difference. their pricing model and lowering their whether they run parallel or at angles 2. Photos are a powerful tool. Digital quality standards. Why? Because passing to each other. If, however, the ridges are photography has simplified the process on a project that does not fit the roofer’s more than 3 feet apart in height, only ven- of obtaining and sharing photos. Roofers business is better than a callback. tilate the higher one or separate the attics. who provide homeowners with a compel- Thankfully, roofing contractors are As wind passes over an externally baffled ling visual of what’s happening on their generous. We know this firsthand because ridge vent, it creates low static pressure, roof and inside their attic make it easier they share tips from the field, job photo- drawing air from the attic. The faster the for them to understand the need for the graphs, and mistakes to avoid that we in wind moves over the baffle, the greater the work being recommended. Before-and-af- turn incorporate into our seminars. This pressure it creates. Typically, wind moves ter photos from previous projects that had invaluable information sharing is one of faster at higher elevations, therefore, the similar troubles can give the homeowner the main reasons our seminar remains higher ridge will be exposed to high wind peace of mind. popular with roofing professionals. speeds. If the wind speed difference is 3. Third-party documentation packs We will continue to offer the free adequate, the pressure at the higher ridge a punch. Roofers who face resistance from Ask the Expert seminars, and we are may be enough to pull air through the homeowners about the need for balanced active members in the Roof Assembly lower ridge vent. Thus, it’s best to separate attic ventilation point to third parties for Ventilation Coalition, whose mission is the attics with plywood or poly sheeting to support. These include Asphalt Roofing to be the leading authority and technical create two distinct attics. Once the attics Manufacturers Association, The Engi- resource on ventilated roof assembly are separated, ventilating all of the ridges neered Wood Association, shingle war- design and performance. is acceptable. ranties and building codes. By referencing 5. Can roof louvers be used low on the requirements and recommendations of Paul Scelsi is marketing communications the roof as intake vents? It’s not a good third parties, roofers strengthen their posi- manager at Air Vent. Since 1998 he has served idea because roof louvers are designed tion that they really do have the home- as the Attic Ventilation: Ask the Expert seminar to be exhaust vents, not intake. If a roof owner’s best interests in mind. leader. He is chairman of the Roof Assembly louver is bringing in air it could also be 4. Using the manufacturer’s tools Ventilation Coalition.