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INTERIORS of BUILDINGS ACOUSTICAL SEALANTS AGE of a BUILDING - how to determine AIR BYPASS LEAKS AIR LEAK DETECTION TOOLS AIR LEAK MINIMIZATION AIR SEALING STRATEGIES ANIMAL ALLERGENS APPLIANCE EFFICIENCY RATINGS ASBESTOS IDENTIFICATION IN BUILDINGS ATTIC LEAKS, CONDENSATION & ATTIC MOLD ATTIC VENTILATION BASEMENT HEAT LOSS BASEMENT LEAKS Moisture or Mold BASEMENT WATERPROOFING BATHROOM VENTILATION BLOWER DOORS & AIR INFILTRATION BRICK LINED WALLS BUCKLED FOUNDATIONS due to INSULATION? CATHEDRAL CEILING INSULATION CHIMNEY INSPECTION DIAGNOSIS & REPAIR COMBUSTION AIR for TIGHT BUILDINGS CRAWL SPACES DEW POINT CALCULATION for WALLS DEW POINT TABLE - CONDENSATION POINT GUIDE ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR ENVIRONMENTAL HAZARDS FIBERGLASS INSULATION FIREPLACE Damage & Unsafe Hearths - Settlement FLAT ROOF MOISTURE & CONDENSATION FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP FLOODS IN BUILDINGS-mold FLOORING CHOICES OVER CONCRETE SLABS FLOORING TYPES & DEFECTS FOUNDATION WATERPROOFING FREEZE-PROOF A BUILDING HEAT LOSS in BUILDINGS HEAT LOSS DETECTION TOOLS HEAT LOSS INDICATORS HEAT LOSS PREVENTION PRIORITIES HEAT LOSS R U & K VALUE CALCULATION Heat Tapes: Use on Roofs for Ice HEATING COST SAVINGS METHODS HOUSEWRAP AIR & VAPOR BARRIERS HUMIDITY LEVEL TARGET ICE DAM PREVENTION Ice Dams: Comparing Two Houses INSULATION IDENTIFICATION GUIDE INSULATION LOCATION in BUILDINGS - WHERE TO INSULATE INSULATION LOCATION for BASEMENTS INSULATION LOCATION for BRICK VENEER WALLS INSULATION LOCATION for CAPES, CRAWLSPACES INSULATION LOCATION for CATHEDRAL CEILINGS INSULATION LOCATION for GREENHOUSE or SOLARIUM INSULATION LOCATION for PASSIVE SOLAR FLOOR SLAB INSULATION LOCATION for SOUND CONTROL in BUILDINGS INSULATION LOCATION for SWIMMING, INDOOR INSULATION R-Values & Properties INSULATION & VENTILATION INSPECTION & IMPROVEMENT ATTIC CONDENSATION CAUSE & CURE Air Bypass Leaks, Thermal Tracking Blocked Soffit Intake Vents BRICK VENEER WALL INSULATION CATHEDRAL CEILING INSULATION ENERGY SAVINGS in BUILDINGS ENERGY SAVINGS PRIORITIES ENERGY SAVINGS RETROFIT CASE STUDY ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE ENERGY SAVINGS RETROFIT OPTIONS FIBERGLASS DUCT, RIGID CONSTRUCTION FRAMING DETAILS for BETTER INSULATION FRAMING DETAILS for DOUBLE WALL HOUSES Inspect Attics for Moisture or Mold Inspect Basements for Moisture or Mold Inspect Building Exterior Inspect the Ridge Vent System from the Attic Inspect the Soffit Vent System from the Attic Insulation Air & Heat Leaks INSULATION R-Values & Properties LOG HOME WALL INSULATION VALUES POLYISOCYANURATE FOAM INSULATION POLYSTYRENE FOAM INSULATION SUPER HI-R INSULATION RADIANT BARRIERS RIGID FOAM USE INDOORS Urea Formaldehyde Foam Insulation UFFI URETHANE FOAM Deterioration, Outgassing Vermiculite Insulation LOG HOME GUIDE MOBILE HOME INSPECTIONS MOISTURE CONTROL in BUILDINGS MOLD INFORMATION CENTER ODORS & SMELLS DIAGNOSIS & CURE PAINT FALURE, DIAGNOSIS, CURE, PREVENTION PLASTER & BEAVERBOARD & DRYWALL RADIANT BARRIERS RADIANT HEAT RADIANT HEAT Floor Mistakes to Avoid RADIANT SLAB FLOORING CHOICES RADIANT SLAB TUBING & FLUID CHOICES ROOF VENTILATION SPECIFICATIONS Inspect the Ridge Vent System from the Attic Inspect the Soffit Vent System from the Attic Insulation Air & Heat Leaks Roof Venting: Intake - Outlet Area Ratios Roof Venting: Proper Locations Roof Venting: Both Ridge & Eaves Venting Needed Roof Venting: Eaves Intake if no Overhang Roof Venting: Soffit Intake Vent-Continuous Roof Venting: Un-Vented Roof Solutions ROOF VENTING ENERGY SAVING DETAILS ROOF VENTING NEEDED? Soffit Ventilation ROT, FUNGUS, TERMITES TERMITE SHIELDS vs TERMITICIDE ROT, TIMBER FRAME SAFETY HAZARDS & INSPECTIONS SEARS KIT HOUSES SOLAR ENERGY SYSTEMS PASSIVE SOLAR DESIGN METHOD PASSIVE SOLAR HEAT PERFORMANCE PASSIVE SOLAR HOME, LOW COST PHOTOVOLTAIC POWER SYSTEMS SLAB INSULATION, PASSIVE SOLAR SOLAR COLLECTOR AIR or GAS COLLECTION SOLAR COLLECTOR FILMS SOLAR COLLECTOR WOOD HOUSINGS SOLAR HEATING SYSTEMS SOLAR HOT WATER HEATERS SOLAR HOUSE EVALUATION SWIMMING POOL SOLAR HEAT, INDOOR SWIMMING POOL SOLAR HEAT, OUTDOOR DIAGNOSIS SOUND CONTROL in BUILDINGS STAIN DIAGNOSIS STAIRS, RAILINGS, LANDINGS, RAMPS STUCCO OVER FOAM INSULATION STRUCTURAL INSPECTIONS & DEFECTS SUMP PUMPS GUIDE THERMAL EXPANSION of MATERIALS THERMAL MASS in BUILDINGS THERMAL MASS in UPSTAIRS THERMAL TRACKING Indicates Heat Loss VAPOR BARRIERS & AIR SEALING at BAND JOISTS VAPOR BARRIERS & CONDENSATION in BUILDINGS VAPOR BARRIERS & HOUSEWRAP VAPOR CONDENSATION & BUILDING SHEATHING VENTILATION in BUILDINGS Air Bypass Leaks, Thermal Tracking ATTIC CONDENSATION CAUSE & CURE BATHROOM VENTILATION Blocked Soffit Intake Vents BLOWER DOORS & AIR INFILTRATION BRICK VENEER WALL INSULATION CATHEDRAL CEILING INSULATION CRAWL SPACE VENTING & Dryout Procedures HEAT LOSS: How to Calculate Heat Loss in a Building HOUSEWRAP AIR & VAPOR BARRIERS HUMIDITY LEVEL TARGET ICE DAM PREVENTION Inspect Attics for Moisture or Mold Inspect Basements for Moisture or Mold Inspect Building Exterior for Moisture Problems Inspect the Ridge Vent System from the Attic Inspect the Soffit Vent System from the Attic Insulation Air & Heat Leaks MOISTURE CONTROL in BUILDINGS MOISTURE CALCULATIONS MOISTURE PROBLEMS: CAUSE & CURE ROOF VENTILATION SPECIFICATIONS Roof Venting: Intake - Outlet Area Ratios Roof Venting: Proper Locations Roof Venting: Both Ridge & Eaves Venting Needed Roof Venting: Eaves Intake if no Overhang Roof Venting: Soffit Intake Vent-Continuous Roof Venting: Un-Vented Roof Solutions ROOF VENTING ENERGY SAVING DETAILS ROOF VENTING NEEDED? Soffit Ventilation VENTILATION DESIGN PROBLEMS & SOLUTIONS WHOLE HOUSE VENTILATION Strategies WATER ENTRY in BUILDINGS WIND TURBINES WINDOWS & DOORS SKYLIGHT LEAK DIAGNOSIS & REPAIR SITE BUILT DOUBLE GLAZED WINDOWS SLOPED GLAZING DETAILS VERTICAL GLAZING DETAILS WINDOW / DOOR ENERGY EFFICIENT, DOE WINDOW LEAKS INTO BASEMENT WINTERIZE A BUILDING WOOD Burning Heaters Fireplaces Stoves More Information  InspectAPedia ® Home & Site Map InspectAPedia Blog - News Updates Air Conditioning & Heat Pumps Bookstore Electrical Environment Exteriors Heating Home Inspection Insulate Ventilate Interiors Mold Inspect/Test Plumbing Water Septic Roofing Structure Accuracy & Bias Pledge Contact Us |
This chapter "How to Inspect in the Attic or Roof Cavity for Signs of an Under-roof Condensation Problem, is 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. Also see CATHEDRAL CEILING INSULATION. 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. I have also measured changes in airflow, temperature, and moisture before and after installing roof venting. © Copyright 2010 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. Inspecting in the Attic or Roof Cavity for Signs of an Under-roof Condensation ProblemAfter examining the eaves or lower roof edges, look up at the ridge for a continuous opening on either side of the ridge board, providing an exit vent path. On some buildings I've found that a ridge vent was installed but the installer just nailed it over the existing roof sheathing, forgetting to cut the necessary opening. "Spot vents" on lower roof slopes, or power vent fans are not as good a substitute for the year-round passive venting provided by a ridge vent. You often will see many drip spots on the attic flooring or insulation (Left photo below). This is caused by moisture condensing on the roofing nails and dropping to the surface below. This is sure evidence of a condensation problem. The pattern of drip marks may be remarkably just like the pattern of roof shingle nails which protrude through the roof sheathing. Winter condensation on the nails, even forming frost in freezing weather, rusts the nails and stains the roof sheathing around them. Frost later melts off of these nails and drips onto the floor below. The pattern may occur more on the cooler or north slope of the roof.
If attic stains are from roof leaks, (right photo above) they will usually be much larger and will appear on the sides of rafters, on larger areas of the roof sheathing, and on larger areas of the attic floor. If you see evidence of extensive roof leaks or condensation leaks, I'd also check the insulation and the attic side of the ceiling drywall for a hidden mold problem. If you see condensation drip stains in the attic (left photo above), you'll be confirming what you suspected from outside -- inadequate ventilation.
How to Inspect the Attic for Moisture - Stains Around Roofing Nails
Rust or stains around roofing nails that protrude through the attic sheathing (they're supposed to stick through) are a clear indication of high attic moisture. Our photograph at above left shows roofing nails protruding through plywood roof sheathing visible in an attic where there is no under-roof condensation or moisture problem. Our photograph at above right shows roofing nails which have rusted and stained the roof plywood in an attic where indoor moisture has risen through the building to condense on the under-side of the roof.
How to Spot Attic Mold Due to High Attic Moisture or Roof Leaks
These photos show mold on attic surfaces due to high moisture in that area. While many inspectors notice dark mold or mold-suspect material on roof framing or roof sheathing, it is at least as important, and often more important to spot the light-colored molds that may also be present - often these are the more hazardous, particularly if building conditions cause air movement downwards out of the attic into the living space or into an attic-located HVAC duct system. The brown/black attic mold on plywood in the left-hand photo is easy to spot and is often an allergen or problematic attic fungus like Cladosporium sp., Pithomyces chartarum, Ulocladium sp., or Aureobasidium pullulans but the light colored mold on the tongue-and-groove pine roof sheathing in the right photo was found to be Penicillium sp. which is more likely to be airborne and transmitted in the building. If you find significant levels or large areas of mold in your attic the mold should be cleaned - that is, removed. Do not rely on magic bullets like sprays alone. The spray approach does not remove the problem mold and it may spread it into otherwise uncontaminated materials like insulation. Don't tear off the roof over a moldy attic: Unless the mold-causing conditions have also rotted framing or delaminated plywood roof sheathing, structural removal/replacement, such as a roof tear-off are unnecessary and inappropriate. But don't forget that if you see attic mold the insulation or ceiling drywall below may also be moldy. See How to Find, Test For, & Remove Mold in Attics for details about where and how to look for attic mold and what to do about it. Share this Article
... Technical Reviewers & References
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. INTERIORS of BUILDINGS Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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INTERIORS of BUILDINGS AIR BYPASS LEAKS AIR LEAK DETECTION TOOLS AIR LEAK MINIMIZATION AIR SEALING STRATEGIES BATHROOM VENTILATION BASEMENT WATERPROOFING BLOWER DOORS & AIR INFILTRATION BRICK LINED WALLS BUCKLED FOUNDATIONS due to INSULATION? CATHEDRAL CEILING INSULATION CRAWL SPACE VENTING & Dryout Procedures MOISTURE, MOLD, ICE DAM LEAKS in ATTICS & ROOFS ATTIC CONDENSATION CAUSE & CURE HEAT LOSS: How to Calculate Heat Loss in a Building HOUSEWRAP AIR & VAPOR BARRIERS HUMIDITY LEVEL TARGET HOUSEWRAP AIR & VAPOR BARRIERS HOUSEWRAP - TYVEK INSTALLATION DETAILS ICE DAM PREVENTION INSULATION INSPECTION & IMPROVEMENT More Information InspectAPedia ® Home & Site Map InspectAPedia Blog - News Updates Air Conditioning & Heat Pumps Bookstore Electrical Environment Exteriors Heating Home Inspection Insulate Ventilate Interiors Plumbing Water Septic Roofing Structure Accuracy & Privacy Policies Contact Us |
More Information on Building Diagnostic Inspections and RepairsMore Reading about Dealing with Attic Mold, Identifying, Removing, and Preventing Mold in AtticsBe 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:
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01/28/2010 - 06/02/1990 - InspectAPedia.com/interiors/atticcond4.htm - © 2010 - 1988 Copyright Daniel Friedman All Rights Reserved - InspectAPedia® is a Registered U.S. Trademark
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