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

• How to Inspect the Building Exterior for Wet Site, Sources of Attic Condensation, Moisture, & Roof Venting Problems & Attic Mold
• How to detect roof venting deficiencies, attic insulation defects, and attic condensation problems

This is chapter 2, "Inspecting the Building Exterior for Wet Site, Sources of Attic Condensation, & Roof Venting 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. These recommendations are based on 30 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. The photograph shown at the top of this page offers compelling evidence of roof leaks into the soffit of this older home. © 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.

A Photo Guide for Inspecting the Building Exterior for Wet Site, Sources of Attic Condensation, & Roof Venting Problems

Here we provide a series of photographs taken of the exterior of buildings, demonstrating visual clues that can predict a problem with ice dam leaks into these homes.

No soffit vents means ice dams

In our photograph at page top, given the age of construction (pre 1900), the brown color of the stains (oils from roof sheathing boards that have been wet), and the shape of the roof edge (probably there was a built-in eaves trough gutter), it is likely that when we inspect the attic interior we'll see that despite the perforated soffit covers, the roof has no intake venting and there has been a long history of ice dam leaks on this building.

Inadequate soffit or ridge venting risks attic moisture, mold, ice dams, as show by these photos

Fake Soffit Vents?

Too often building exterior renovations include covering an existing, solid, un-vented building soffit or eaves with perforated panels, forming a "faux vent" system since the perforations are not really passing any air into the building attic.

It's easy to spot this condition both by visual inspection and, where accessible, by pressing on the perforated panels - if they are over an open space they will move easily.

In our photograph at left, although perforated panels are installed on soffits of this older home, we see extensive leak stains on that material. From outside we posit that either the perforated panels were installed over solid wood - there is no actual soffit intake venting for the attic, or the building simply has little or no attic insulation, resulting in lots of heat loss into the attic during winter months, combined with freezing of melting snow at the colder roof edges.

No Soffits so No Soffit Vents Means Ice Dams and Wall Leaks are Likely

The home shown in our photograph at left was built with no roof overhang whatsoever - or no roof soffits or eaves extension past the building walls. Not only does roof runoff too often run down the exterior wall surface, inviting rot or insect damage or wall leaks, but also this construction makes it tricky to obtain any roof cavity intake venting.

Special products such as the Hicks (TM) starter vent can be used at roof eaves in this location, but an air path must also be provided inside under the roof decking.

The window at the building right corner tells us that cathedral ceilings were probably installed inside this home - under-roof venting would still be a good step to avoid roof cavity condensation, leaks, mold, or related damage.

Tiny Gable End Vents can Predict Ice Dams and Inadequate Attic Ventilation on Buildings

The photograph shown at left demonstrates a tiny gable-end vent in an older building.

This home combines stone construction, multiple shingle layers, shaded site with (unseen) no other attic intake or outlet ventilation, to make attic condensation problems and seasonal ice dam leaks likely.

Photographs of Building Siding Stains Can Indicate Ice Dam Leaks

This photo shows siding stains caused by roof ice dam leaks into the wall cavity. Notice that the soffit is un-vented on this older home. Roof leaks into the wall cavity have run down the walls and exited between clapboards, leaving stains and peeling paint.

Roof leaks in this area from any cause, ice dams or work, leaky roofing materials will all produce this effect.

Photos of Use of Heating Tapes on Roof Edges Tells the Ice Dam Story

This photo shows roof edge heating tapes installed by an owner to attempt to melt channels through ice that may accumulate at the roof eaves in winter. This is an inexpensive band-aid that may be sufficient if ice dam formation on a roof is rare and/or it is difficult to install good under-roof venting.

This roof has eaves and a ridge that could have been vented.

If a roof shape prevents easy installation of under-roof venting, or if a home is located where building custom excludes under-roof venting, use of an ice-and-water shield product under the shingles at roof edges, or use of metal covering the lower roof slopes are other measures taken to prevent ice dam leaks into the building interior.

Signs of Roof Ice Dam Problems Can Be Seen in Any Season

In addition to our photos showing missing roof intake or outlet venting, roof leak stains, and similar clues, you may be able to spot evidence of attempts to remove roof ice dams by chopping at the ice itself.

Usually attempts to remove roof ice by chopping at it results in damaged roof shingles and sometimes holes in nearby flashing or gutters as shown in this photo.

You'll also spot chop or cut marks in roof shingles at the lower roof edges when this procedure has been attempted.

A Summary of Inspection Tips for Roof Venting & Ice Dam Problems

The first signs of a probable attic condensation problem may there for observation before even entering a building.

Look at the roof. If you're in a cold climate during winter months you may see areas of snow-melt showing where there is an insulation defect. Or you may see actual severe ice dams at the roof eaves. If the shingles are exposed look for signs of attic moisture in their condition: if there is a high level of attic moisture, unless the roof is quite young, you might see puckered shingles in the classic "fishmouth" pattern.

This shingle curling is quite obvious. If you inspect the exterior roof surface first, on an old roof you'll note shingles which are brittle and which may crack or break. (Don't walk on such surfaces.) If the roof sheathing is plywood, you may sense surface deflection which could simply be thin 3/8" plywood (no longer permitted in most jurisdictions) or it could be damaged from heat or moisture. (Beware of falling through).

1. Look at the ridge. If there is no ridge vent there is no good outlet for an under-roof attic venting system and this roof will be difficult to ventilate.
2. Look at the eaves or soffits. If there are no continuous intake vents at the soffits, this roof will be difficult to ventilate.
3. Look at the roof lines. If the building has flat roofs, low-slope roofs, roofs abutting Building walls, or complex roof lines, these roofs will be difficult to ventilate.

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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