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Comparing Houses With and Without Roof Ventilation - Attic Condensation, Moisture, & Ice Dam Leaks InteriorAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

• A comparison of two homes, with and without working roof ventilation shows the effects of ice dams, leaks, attic moisture, and risk of attic mold
• How to detect roof venting deficiencies, attic insulation defects, and attic condensation problems

This is chapter 3, "Comparing Two Identical Houses, With and Without Roof Ventilation and Insulation to Understand Attic Moisture Problems", part of our discussion of "Attic Condensation". 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.

The photograph at page top shows the author's introduction to roof ice dams at 25 King Drive in Poughkeepsie, NY in 1970. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links 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.

Comparing Two Identical Houses, With and Without Roof Ventilation and Insulation to Understand Attic Moisture Problems

On two identical 1860's Wappingers Falls NY "Bleachery" historic houses shown in these photos, the one with no melted snow was renovated to include continuous soffit and ridge venting and good attic insulation. Look at the difference in the two roofs on the same winter day. These homes, located on West Street in the village of Wappingers Falls, New York, were built to house workers at nearby mills powered by water from Wappingers Creek. When the homes were built they lacked central heating, storm windows, siding, caulking, and insulation. They were drafty. Interior moisture and condensation were less likely to damage the structure than today, nearly 130 years later, when the energy improvements listed have been added to the homes, making them tighter but also providing indoor moisture sources such as from bathing or cooking. The house whose roof shows melted snow and bare roof slates (beware of nasty owner) has inadequate venting and inadequate insulation, giving rise to snow melt and ice damming, and almost certainly to attic condensation and moisture. The house whose roof is covered with a uniform blanket of un-melted snow, (renovated by the author) was improved to add attic insulation in the attic floor as well as continuous soffit intake venting and ridge outlet venting. After these vents were added we also closed-off the gable end vents (not shown) to assure that airflow moved over the desired pathway. The builders of this house had blocked the soffits with boards on edge between each rafter pair in an effort to "warm up" the cold attic. We removed these blocking boards to assure a proper airflow.

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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