InspectAPedia.com InspectAPedia®
Google
InspectAPedia
 

Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair

Ask a Question or Search InspectAPedia

  • HOME
  • AIR CONDITIONING
  • DAMAGE ASSESSMENT
  • ELECTRICAL
  • EXTERIORS
  • HEATING
  • HOME INSPECTION
  • INTERIORS
  • PLUMBING
  • ROOFING
  • SEPTIC SYSTEMS
  • STRUCTURE
  • WATER SUPPLY
  • ENERGY SAVINGS
  • ENVIRONMENT
  • INDOOR AIR IAQ
  • INSULATION
  • MOLD INSPECT TEST REMOVE
  • NOISE
  • ODORS
  • SOLAR ENERGY
  • VENTILATION
  • EXPERTS DIRECTORY
  • CONTACT US



InspectAPedia ® Home

VENTILATION in BUILDINGS

AIR BYPASS LEAKS
AIR LEAK DETECTION TOOLS
AIR LEAK MINIMIZATION
AIR LEAK SEALING PROCEDURE
AIR POLLUTANTS, COMMON INDOOR
AIR SEALING STRATEGIES
AIR TEST FOR MOLD: ACCURACY
AIR TEST SAMPLING CASSETTE STUDY
ANIMAL ODORS IN buildings
ATTIC LEAKS, CONDENSATION & MOLD

BASEMENT CEILING VAPOR BARRIER
BASEMENT HEAT LOSS
BASEMENT LEAKS, INSPECT FOR
BATHROOM VENTILATION
BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING
BRICK WALL DRAINAGE WEEP HOLES
BUCKLED FOUNDATIONS due to INSULATION?
BUILDING NOISE DIAGNOSIS & CURE

CATHEDRAL CEILING VENTILATION
CEILINGS, DROP or SUSPENDED PANEL
CHIMNEY INSPECTION DIAGNOSIS & REPAIR
COMBUSTION AIR for TIGHT buildings
COOLING LOAD REDUCTION by ROOF VENTS
CONDENSATION or SWEATING PIPES, TANKS
CONDENSATION on WINDOWS & SKYLIGHTS
CRAWL SPACES

DECK & PORCH CONSTRUCTION
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DRYER VENTING

FIBERGLASS INSULATION
FIREPLACES & HEARTHS
FLAT ROOF MOISTURE & CONDENSATION
FORMALDEHYDE HAZARDS
FRAMING DETAILS for BETTER INSULATION
FRAMING DETAILS for DOUBLE WALL HOUSES
FREEZE-PROOF A BUILDING
FROST HEAVES, FOUNDATION, SLAB

GREEN BUILDING CONSTRUCTION CODES GUIDES
GREENHOUSE DESIGN for SOLAR HEATING
GREENHOUSE / SUNSPACE GLARE

HEAT LOSS in BUILDINGS
HEAT LOSS DETECTION TOOLS
HEAT LOSS INDICATORS
HEAT LOSS PREVENTION PRIORITIES
HEAT LOSS R U & K VALUE CALCULATION
HOT ROOF DESIGNS: Un-Vented Roof Solutions
HOUSEWRAP AIR & VAPOR BARRIERS
HOUSE DOCTOR, how-to be
HUMIDITY LEVEL TARGET

ICE DAM PREVENTION
INDOOR AIR HAZARDS TABLE
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
INSULATION CHOICES
Insulation Air & Heat Leaks
INSULATION INSPECTION & IMPROVEMENT
INSULATION R-Values & Properties

LOG HOME GUIDE

MOISTURE CONTROL in BUILDINGS
MOLD: A COMPLETE GUIDE TO MOLD

Nanomaterials Hazards
NOISE / SOUND DIAGNOSIS & CURE

ODORS & SMELLS DIAGNOSIS & CURE

PAINT FALURE, DIAGNOSIS, CURE, PREVENTION

RADIANT BARRIERS
RADIANT HEAT
ROOF VENTILATION SPECIFICATIONS

SHEATHING, FOIL FACED - VENTS
SOFFIT VENTILATION
SOUND CONTROL in buildings
STAIN DIAGNOSIS on BUILDING EXTERIORS
STAIN DIAGNOSIS on BUILDING INTERIORS
STUCCO WAll FAILURES DUE TO WEATHER
STUCCO WALL METHODS & INSTALLATION
STUCCO OVER FOAM INSULATION
STUCCO PAINT FAILURES
SWEATING (CONDENSATION) on PIPES, TANKS

THERMAL MASS in buildings
THERMAL TRACKING Indicates Heat Loss

VAPOR BARRIERS & AIR SEALING at BAND JOISTS
VAPOR BARRIERS & HOUSEWRAP
VAPOR CONDENSATION & BUILDING SHEATHING
VENTILATION in BUILDINGS

WIND WASHING INSULATION At EAVES
WINDOWS & DOORS
WINTERIZE A BUILDING
WOOD, COAL STOVES & FIREPLACES
WOOD STOVE SAFETY

ZONE DAMPERS
ZONE VALVES


More Information

Ridge vent viewed from atticHow to Inspect Ridge Vents from the Attic
     

  • Guide to Inspecting Attic and Under-Roof Ventilation - what's at the ridge?
    • How to Correct Inadequate Attic Venting to Stop Attic Condensation, Ice Dam Leaks, Attic Mold, & Roof Structure Damage
    • How to detect roof venting deficiencies, attic insulation defects, and attic condensation problems
  • Questions & Answers about attic moisture, condensation & ventilation: check the ridge vent from inside the attic
  • References

Click to Show or Hide Related Topics

  • ROOF VENTILATION SPECIFICATIONS - home
  • AIR & HEAT LEAKS
  • AIR CHANGE RATE ACH HEAT SAVINGS
  • AIR LEAK DETECTION TOOLS - home
  • ATTIC LEAKS, CONDENSATION & MOLD
  • ATTIC MOISTURE or MOLD
  • ATTIC VENTILATION
  • ATTIC CONDENSATION CAUSE & CURE
  • BASEMENT MOISTURE to ATTIC
  • BLOCKED SOFFIT INTAKE VENTS
  • BLOWER DOORS & AIR INFILTRATION
  • CATHEDRAL CEILING VENTILATION
  • COOLING LOAD REDUCTION by ROOF VENTS
  • FLAT ROOF MOISTURE & CONDENSATION
  • HEAT TAPES & CABLES on Roofs for Ice Dams
  • HEAT LOSS in BUILDINGS - home
  • HEAT RECOVERY VENTILATORS
  • HOT ROOF DESIGNS: Un-Vented Roof Solutions
  • HUMIDITY LEVEL TARGET
  • ICE DAM PREVENTION
  • ICE DAM CURE: Comparing Two Houses
  • INDOOR AIR QUALITY & HOUSE TIGHTNESS
  • RIDGE VENT, ATTIC INSPECTION
  • ROOF VENTILATION SPECIFICATIONS
  • Inspect Building Exterior - Roof Venting
  • ROOF VENTIILATION INTAKE-OUTLET RATIO
  • ROOF VENT LOCATIONS
  • ROOF VENT SOFFIT & RIDGE NEED
  • ROOF VENT if NO SOFFIT
  • ROOF VENT SOFFIT, CONTINUOUS
  • ROOF VENTING ENERGY SAVING DETAILS
  • ROOF VENTING NEEDED?
  • ROOF VENTING ENERGY SAVING DETAILS
  • ROOF VENTING NEEDED?
  • SKYLIGHT VENTILATION DETAILS
  • SOFFIT INTAKE BLOCKED
  • SOFFIT VENTILATION SPECS
  • UN-VENTED ROOF SOLUTIONS
  • VENTILATION in BUILDINGS - home
  • VENTILATION DESIGN PROBLEMS & SOLUTIONS
  • VENTILATION, WHOLE HOUSE STRATEGIES
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Roof venting at the ridge, inspect from attic: this article describes common attic ventilation defects easily observed at the ridge or high point of the roof, as visible from the attic or building interior.

Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.

Inspecting the Ridge Vent System from the Attic

this simple sketch shows the optimium attic vent design with inflow at eaves and outflow at ridge

This article describes inspection methods and clues to detect roof venting deficiencies, insulation defects, and attic condensation problems in buildings. It describes proper roof ventilation placement, amounts, and other details. This discussion is part of "How to Correct Improper or Inadequate Attic or Under-Roof Ventilation in buildings" in our discussion of "Attic Condensation".

You need the gap at the ridge (or "peak") of the roof for the ridge vent to work. Of course some roof shapes such as pyramid or shed roofs merit special techniques to obtain effective intake and exit venting.

But for a simple gable-styled roof structure, here is what a ridge vent looks like from inside the attic of a home.

The ridge vent cut at the roof ridge or peak extends the entire length of the ridge, stopping just a foot or so from either end, and should give 1.5” to 2.5” of open space (no plywood) on either side of the ridge board for attic air to escape out through the ridge vent.


Fake ridge vent Fake ridge vent

Fake ridge vents: As depicted by the pair of photographs above, sometimes we find that a builder has installed a ridge vent from outside but s/he failed to cut away the roof plywood to provide the exit air path to properly vent the attic. In this case this lazy man's faux ridge vent installed outside should be removed along with any ridge cap shingles below it.

The ridge vent slot should be cut to remove roof sheathing as we described just above (or best, following instructions of the ridge vent manufacturer).

Do not cut into the rafters themselves. Then install the ridge vent again and you'll have a working roof exit vent system.

Blocked ridge vent

Roofing Felt Obstructed ridge vents: It’s less common for us to find that a builder cut away plywood for the ridge vent, but that s/he installed building paper or more likely roofing felt over the opening before installing the ridge vent.

In this case just cut away the building paper to expose the underside of the plastic ridge vent mesh, plastic Cor-A-Vent material (looks like a plastic version of the edge of a cardboard box)  or the opening into the aluminum ridge vent (depending on which type of ridge vent was installed).

Check that the ridge vent material itself is not blocked by building paper (which you can simply cut away). 


Shingles over ridge vent

Shingle-obstructed ridge vent warning: If when inspecting from the attic and looking up into the slot of removed-plywood at the ridge of the roof you see the under side of a roof shingle, either the roofer made the ridge vent a bit longer than needed, or something else is going on that we’d need to check from outside.

In any case, do not cut away roofing shingles over the ridge vent as you might invite a roof leak.

If your attic or under-roof cavity has a problem with moisture or mold, installing continuous, un-blocked, aggressive exit venting at the ridge is an important step.


Frequently Asked Questions (FAQs)

...

Ask a Question or Search InspectApedia

Questions & answers or comments about attic moisture, condensation & ventilation: check the ridge vent from inside the attic

Ask a Question or Enter Search Terms in the InspectApedia search box just below.

Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

  • Thanks to reader F. Terrell for careful technical editing 06/18/2010
  • Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. (727) 595-4211 mark@BestTampaInspector.com 11/06 & 12/08
  • John Annunziata, P.E. - NY Metro ASHI during informal chapter discussions about roof and attic ventilation options (1986-1996).
  • Carson, Dunlop &
Associates Ltd., TorontoCarson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides:
    • Commercial Building Inspection Courses - protocol ASTM Standard E 2018-08 for Property Condition Assessments
    • Home Inspection Education Courses including home study & live classes at eleven colleges & universities.
    • Home Inspection Education Home Study Courses - ASHI@Home Training 10-course program.
      Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
    • The Home Reference Book, a reference & inspection report product for building owners & inspectors.
      Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
    • The Home Reference eBook, an electronic version for PCs, the iPad, iPhone, & Android smart phones.
      Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter inspectaehrb in the order payment page "Promo/Redemption" space.
    • The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors.
      Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
    • The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones.
  • "Energy Savers: Whole-House Supply Ventilation Systems [copy on file as /interiors/Energy_Savers_Whole-House_Supply_Vent.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11880?print
  • "Energy Savers: Whole-House Exhaust Ventilation Systems [copy on file as /interiors/Energy_Savers_Whole-House_Exhaust.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11870
  • "Energy Savers: Ventilation [copy on file as /interiors/Energy_Savers_Ventilation.pdf ] - ", U.S. Department of Energy
  • "Energy Savers: Natural Ventilation [copy on file as /interiors/Energy_Savers_Natural_Ventilation.pdf ] - ", U.S. Department of Energy
  • "Energy Savers: Energy Recovery Ventilation Systems [copy on file as /interiors/Energy_Savers_Energy_Recovery_Venting.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11900
  • "Energy Savers: Detecting Air Leaks [copy on file as /interiors/Energy_Savers_Detect_Air_Leaks.pdf ] - ", U.S. Department of Energy
  • "Energy Savers: Air Sealing [copy on file as /interiors/Energy_Savers_Air_Sealing_1.pdf ] - ", U.S. Department of Energy
  • Humidity: What indoor humidity should we maintain in order to avoid a mold problem?
  • "Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
  • ...

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

  • Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
  • Home Reference Book - Carson DunlopThe Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

    Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
  • ...

HOME ABOUT CONTACT COPYING DESCRIPTION POLICIES PRINTING PRIVACY © 2013 Copyright InspectAPedia.com