Should I Close My Attic Gable Vents? - Fine Homebuilding FHB Logo Facebook LinkedIn Email Pinterest Twitter Instagram Plus Icon Close Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Main Menu
Subscribe

In every issue you'll find...

  • Expert insights on techniques and principles
  • Unbiased tool reviews
  • Step-by-step details to master the job
  • Field-tested advice and know-how
Subscribe Now!
Subscribe
  • How-To
  • Design
  • Tools & Materials
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
  • Join
  • Log In
Main Menu Subscribe

Fine Homebuilding Project Guides

Roofing

Guide Home
Chapter
  • Tools and Materials
  • Roof Replacement and Reroofing
  • Roof Ventilation
  • Waterproofing
  • Installing Asphalt Shingles
  • Installing Other Types of Roofs
  • Roof Maintenance and Repair
Ask the Experts

Should I Close My Attic Gable Vents?

Get insight into the complicated relationship between ridge vents, gable vents, and attic floors.

By Bruce Harley Issue 225
Article Image

No short-circuiting here. Even with the gable vents open, air continues to enter the soffit vents and to move upward due to the stack effect. While some of it exits through the gable vents and some exits through the ridge vent, these outlets are not in competition with each other.

Q:

As built, the attic of our 22-year-old house was ventilated with gable vents and soffit vents. We replaced the roof recently and when we did we added a ridge vent. According to the guy who writes the home-improvement column in the local paper, if you add a ridge vent, you should close off the gable vents. If not, the air pathway through the attic will be short-circuited, flowing only from the gable vents to the ridge vent and not ventilating the lower part of the attic. The roofer says closing the gable vents isn’t necessary. Who is right?

SUZYPQ from the Breaktime forum

A:

Bruce Harley, technical director of Conservation Services Group in Westborough, Mass., responds:

Everyone has an opinion about this stuff, and most folks overthink it. Here’s what you need to know — the newspaper guy is wrong; your roofer is right. There is no need to block the gable vents unless they are prone to collecting windblown rain and snow. (This would not be related to adding the ridge vent; that would have already been true before the roof work.)

Although unvented roof assemblies work if they are built properly, attic venting is a good thing for most houses, and having too much venting will not harm the structure. Airflow promotes drying, whether the water comes from inside (condensation in the winter) or outside (roofing or flashing leaks).

For any attic venting to work properly, and for the house to work properly, you must thoroughly air-seal and insulate the attic floor. If there are air leaks between the attic and the living space, attic vents become outlets for conditioned air driven by the stack effect. If you don’t seal the leaks in the attic floor, the heat loss can melt snow (causing ice dams) and create condensation and moisture problems.

Air leaks can even increase the risk of combustion backdrafting, especially for a fireplace with an exterior chimney.

Once leaks are sealed and insulation is installed, the attic is an isolated space. The main force that now drives venting is solar radiation on the roof. That heats up  attic air. Adding exhaust vents high on the roof can help to accentuate the inflow of air through the soffit vents. It doesn’t matter if these exhaust vents are ridge vents, gable vents, roof vents, or some combination.

If windblown rain or snow is frequently entering the gable vents, close them. Don’t worry about an airtight seal; just nail a board over the opening from the inside.

To summarize: Seal air leaks in your attic floor so that roof venting doesn’t suck conditioned air into the attic and cause moisture problems. Adding a ridge vent is a fine idea, and don’t worry about it competing with the gable vents. If the gable vents aren’t letting in rain or snow, leave them alone.

Roof ventilation is a complex topic, particularly for cathedral ceilings where there is no attic between the living space and the roof. Improperly designed roof assemblies can lead to a variety of problems, including moisture accumulation and decay. Although unconditioned attics like this one are the simplest assemblies to ventilate, complex roof shapes make the job more difficult.

More about attic venting:

Attic Ventilation Strategies — Simple mistakes can undo the best of intentions for venting a roof. Here are some things to keep in mind.

Venting the Roof — With today’s construction methods, the minimum code requirements may not be enough.

A Crash Course in Roof Venting — Building scientist Joseph Lstiburek explains when to vent your roof, when not to, and how to execute each approach successfully.

Ice Dams — Ice dams are not a roofing problem; they’re an air-sealing problem.

Site-Built Approach to Roof Ventilation — When rafter bays will be filled with dense-packed cellulose, you’re going to need rigid vent baffles.

Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers.

Sign Up
X
X
Previous: Three Reasons We Vented the FHB House Roof Next: Does a Roof Need a Ridge Vent?

Guide

Roofing

Chapter

Roof Ventilation

View Comments

  1. ripstorm | Dec 17, 2018 03:35pm | #1

    Absolutely correct. The important thing as you say is the insulation and sealing. Note the air passage up from the soffits - don't block this with insulation. Don't know where these local paper guys get their info, probably same place as the internet experts. Gable vents, soffit vents, ridge vents, cold up there.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Roofing

Roofing

A complete resource that includes the best materials and the right techniques to build a sturdy, leak-free, attractive roof on any house

View Project Guide

View All Project Guides »

Become a member and get unlimited site access, including the Roofing Project Guide.

Start Free Trial

Tools and Materials
  • Roof Coverings
  • Roofing Materials
  • Power Tools
  • Handy Helpers
  • Staging and Ladders
  • Safety Equipment
Roof Replacement and Reroofing
  • Preparing the Old Roof
  • Sheathing
  • Installing the New Roof
Roof Ventilation
  • Venting Basics
  • Installation
Waterproofing
  • Underlayment
  • Drip Edge
  • Flashing Adjoining Walls
  • Dormer and Skylight Flashing
  • Chimney Flashing
  • Vent Flashing
  • Gutters
Installing Asphalt Shingles
  • Calculating Shingles
  • Layout
  • Installation
  • Valleys
Installing Other Types of Roofs
  • Cedar Shingles
  • Metal
  • Low-Slope Roofs
  • Slate and Tile
Roof Maintenance and Repair
  • Assessing the Problem
  • Repairing Asphalt-Shingle Roofs
  • Other Roofing Repairs

Fine Homebuilding

Follow

Newsletter

Get home building tips, offers, and expert advice in your inbox

Sign Up See all newsletters

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Manage Preferences

Taunton Network

  • Green Building Advisor
  • Fine Woodworking
  • Fine Gardening
  • Threads
  • About
  • Contact
  • Advertise
  • Privacy Policy
  • Careers
  • Copyright
  • Terms of Use
  • Accessibility

© 2021 The Taunton Press, Inc. All rights reserved.

    Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Reader Projects
  • Magazine
  • Members
  • FHB House
  • Podcasts

  • FHB Podcast
  • ProTalk
  • Account

  • Log In
  • Join

    Podcasts

  • FHB Podcast
  • ProTalk
  • Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

    Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

    All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

    Shop the Store

  • Books
  • DVDs
  • Taunton Workshops

    More

  • FHB Ambassadors
  • Reader Projects
  • Podcast
  • Customer Support

    Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Sign Up See all newsletters

Follow

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 52%

Subscribe

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in