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How to Detect and Correct Attic Condensation & Prevent Ice Dam Leaks in Buildings InteriorAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

• How to detect & correct roof venting deficiencies, attic insulation defects, and attic moisture or condensation problems

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. These recommendations are based on 40 years of building inspections, on the observation of the locations of moisture, mold, ice dams, condensation stains, and other clues in buildings, and on the correlation of these clues with the roof venting conditions at those properties. I have also measured changes in airflow, temperature, and moisture before and after installing roof venting. More in-depth, un-biased, expert information on these topics and on building defect inspection, diagnosis, & repair can be found at "More Information below. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use the links at page left to navigate this document or to go to Other Website Topics. Green links at left show where you are in our document & website.

Attic Condensation and Roof Leaks as a Source of Building Mold - Diagnosis and Cure

Sources of Attic Mold: Roof leaks or, alternatively, high levels of attic moisture due to a combination of inadequate attic (soffit intake and ridge outlet) ventilation combine with building moisture sources (such as a chronic or even a single-event wet basement, plumbing leaks, or a leaky roof from roof failure or from ice dams) are likely to cause excessive moisture or actual wet conditions in an attic. High attic moisture levels or actual wet attic conditions invite extensive mold growth.

Visible mold may appear on wood surfaces in an attic such as on rafters or roof sheathing. Hidden mold may be present and may be even more of a problem if it forms in insulation or in the ducts and air handler of an air conditioning or heating/air conditioning system. Typical building air convection currents tend to move air up and out from lower to upper building levels, so one would not think that much mold would move down from an attic into the living area. But important exceptions to this can quickly move problem mold from an attic into a living area. Conditions moving mold downwards from an attic include

• Mold growth in HVAC ducts or air handlers found in an attic
• Mold on any attic surface or in attic insulation if it is a species producing airborne spores and if the building uses a whole house ventilating fan, especially if there is inadequate exit venting for the fan operation. This condition pressurizes the attic and moves mold down through various openings into the floors below.
• Mold on building surfaces in an attic or attic knee wall space which opens onto or has a knee wall common with an upper floor living space such as a bedroom.

Building Exteriors Leaks and Mold No mold cleanup project will be successful unless you correct the conditions that caused mold growth in the first place. An expert inspection and report should find and suggest remedies for site and building exterior conditions that produce mold or for building areas that serve as a mold reservoir or as amplifiers for allergens, mold, mildew, excessive pollen or pet dander.

The basic steps: find all unwanted moisture sources, correct appropriate building, site, landscaping, & construction details. 90% of the wet basements and crawl spaces I see are caused by bad or missing roof gutters and downspouts.

An IAQ investigator who has training and experience in building science, mycology (mold science), and IAQ, or in some cases an experienced ASHI-Certified home inspector or sick building investigator who is who has a similar in-depth understanding of construction failures can be helpful at this step.

Technical Reviewers

Particular thanks are due to experts and also consumers who read these articles and suggest corrections, changes, and additions to the material. Content suggestions, technical corrections and content critique are invited for any of the content at our website.

• Alan Carson Carson Dunlop Associates, Toronto, Ontario. Mr. Carson is a home inspection professional, educator, researcher, writer, and a principal of Carson Dunlop Associates, a Toronto home inspection and education firm. Mr. Carson is a past president of ASHI, the American Society of Home Inspectors Some great illustrations of the proper under-roof ventilation pathways are offered by Carson Dunlop.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 11/06Daniel Friedman - principal author Daniel Friedman, editing, expanding, adding to comments from John Annunziata, P.E. - NY Metro ASHI informal chapter discussions.
• Technical reviewers are invited to comment or ask questions - contact us

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website. If you just "scroll down" you'll miss some important articles. See links at page left.

MOISTURE, MOLD, ICE DAM LEAKS in ATTICS & ROOFS
Attic Condensation
Inspect Building Exterior
Comparing Two Houses
Inspect Basements for Moisture or Mold
Inspect Attics for Moisture or Mold
Inspect the Ridge Vent System from the Attic
Inspect the Soffit Vent System from the Attic
Blocked Soffit Intake Vents
Correcting Roof Ventilation
Ridge and Eaves Venting Both Needed
Continuous Soffit Intake Venting Needed
Proper Roof Vent Location
Roof Vent Area Ratios
Un-Vented Roof Solutions
Air Bypass Leaks, Thermal Tracking

More Information on Effects of Building Moisture & Building Diagnostic Inspections and Repairs

More Reading about Dealing with Attic Mold, Identifying, Removing, and Preventing Mold in Attics

Be sure to review HOW TO FIND MOLD: How to Inspect Homes and Other Buildings for Mold - the Basics of How to Find Problem Mold Indoors in our Mold Action Guide. Here are other articles that will be helpful in evaluating attic mold presence, causes, and cures:

• What Mold and Allergens Look Like: mold identification photos to help identify mold - choosing what to sample in buildings
• How to Clean Moldy Wood Framing & Sheathing How to clean/seal mold from/on exposed lumber or plywood subfloor or roof sheathing indoors - some suggestions based on our field and laboratory research
• Lighting, proper use of: proper aiming of a good flashlight can disclose hard to see but toxic light or white mold colonies on walls.
• Mold spores in the Home - a Photo ID Library for detection and identification of mold allergens.
• How to Find and Test For Mold in Buildings A "how to" photo and text primer on finding and choosing the right spots to test for mold in buildings
• Stuff that is not mold but is often mistaken for it - things you may not want to test. Also, not all "black mold" is toxic - here are examples of harmless black mold.
• Simple Adhesive Tape Sampling of Moldy Surfaces - how to send a mold sample to our lab
• Mold Sampling Methods in the Indoor Environment - In-depth article: detailed critique of popular mold testing methods - Is your mold test kit worth the bother?
• Humidity: What indoor humidity should we maintain in order to avoid a mold problem?
• Mold-Resistant Building Practices, advice from an expert on how to prevent mold after a building flood and how to prevent mold growth in buildings by selection of building materials and by anti-mold construction details.

InspectAPedia ^TM Home & Site Map - Building Inspection, Diagnosis, & Repair, Environmental Inspection & Testing - Research Website

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Home Inspection Construction Consulting Services & advice for home buyers

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

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