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EXTERIORS of BUILDINGS
INTERIORS of BUILDINGS
AIR BYPASS LEAKS
AIR LEAK DETECTION TOOLS
AIR LEAK MINIMIZATION
AIR SEALING STRATEGIES
BATHROOM VENTILATION
BASEMENT HEAT LOSS
BASEMENT LEAKS Moisture or Mold
BASEMENT WATERPROOFING
BLOWER DOORS & AIR INFILTRATION
BRICK LINED WALLS
BUCKLED FOUNDATIONS due to INSULATION?
CATHEDRAL CEILING INSULATION
FREEZE-PROOF A BUILDING
ATTIC CONDENSATION CAUSE & CURE
CATHEDRAL CEILING INSULATION
Heat Tapes: Use on Roofs for Ice
HEAT LOSS: How to Calculate Heat Loss in a Building
HOUSEWRAP AIR & VAPOR BARRIERS
HUMIDITY LEVEL TARGET
ICE DAM PREVENTION
INSULATION INSPECTION & IMPROVEMENT
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
ROOF VENTILATION SPECIFICATIONS
HEAT LOSS: How to Calculate Heat Loss in a Building
HOUSEWRAP AIR & VAPOR BARRIERS
HUMIDITY LEVEL TARGET
ICE DAM PREVENTION
INSULATION INSPECTION & IMPROVEMENT
MOISTURE CONTROL in BUILDINGS
THERMAL TRACKING & HEAT LOSS
VAPOR BARRIERS & AIR SEALING at BAND JOISTS
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VAPOR BARRIERS & HOUSEWRAP
VAPOR CONDENSATION & BUILDING SHEATHING
VENTILATION in BUILDINGS
WATER ENTRY in BUILDINGS
  ATTIC LEAKS Moisture or Mold
  BASEMENT De-Watering Systems
  BASEMENT HEAT LOSS
  BASEMENT LEAKS Moisture or Mold
    Cold Pour Joint Leaks
    Form Tie Leaks
    Wall Crack Leaks
    Floor-Wall Joint Leaks
  BASEMENT WATERPROOFING
  BASEMENT DE-WATERING SYSTEMS
  EXTERIOR WATER SOURCE ELIMINATION
  FOUNDATION DRAINS & FRENCH DRAINS
  FOUNDATION WATERPROOFING
  GEOTEXTILES & DRAINAGE MATS
  SEALERS, Basement Floor & Wall Moisture
  SITE DRAINAGE
  SUMP PUMPS GUIDE
  WET BASEMENT PREVENTION
  WET BASEMENT PREVENTION
  CRAWL SPACE Dryout Proc
  Chimney Leaks
  CRAWL SPACE Dryout Procedures
  DEW POINT CALCULATION for WALLS
  DEW POINT TABLE - CONDENSATION POINT GUIDE
  EFFLORESCENCE, Salts & White / Brown Deposits
  FLOOD Damage Assessment & Repairs
  FLOOD DAMAGED FOUNDATIONS
  FLOOD VENTS
  FLOODS IN BUILDINGS-priorities
  FOUNDATION WATERPROOFING
  HUMIDITY CONTROL & TARGETS INDOORS
  HOUSEWRAP AIR & VAPOR BARRIERS
  LOG HOME Leak Diagnosis & Cure
  LOG HOME Condensation &Moisture
  MOISTURE CALCULATIONS
  MOISTURE PROBLEMS: CAUSE & CURE
  MOLD in BUILDINGS
  SEWAGE CONTAMINATION
  SUMP PUMPS GUIDE
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

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Evidence of a wet basement from roof spillage How to Inspect for Basement Leaks or Moisture - a Step in Detecting & Correcting Attic Condensation, Ice Dam Leaks, & Indoor Mold
InspectAPedia®  -    

  • How to Inspect for Basement Leaks or Moisture as a Step in Detecting and Correcting Attic Condensation, Ice Dam Leaks, and Indoor Mold Contamination
  • Basement waterproofing guide to choices of sealants, membranes, drainage systems, basement de-watering systems, sump pumps
  • How to detect roof venting deficiencies, attic insulation defects, and attic condensation problems
Our site offers impartial, unbiased advice without conflicts of interest. We will block advertisements which we discover or readers inform us are associated with bad business practices, false-advertising, or junk science. Our contact info is at InspectAPedia.com/appointment.htm.

Inspecting in the Basement for Sources of Building Moisture Appearing as Attic Condensation and building mold describes common water entry or leak points in basements and crawl spaces as part of our discussion of both ATTIC LEAKS Moisture or Mold (where did that moisture originate?) and also WATER ENTRY in BUILDINGS (how to keep a building dry and at proper moisture levels). The photograph at page top shows a very wet basement with water stains high on the foundation walls - telling us that the cause of this water entry is obviously not "rising damp" nor "construction over an underground stream".

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 35 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 as well as frequent literature review and discussion among professionals.

Readers should also see WET BASEMENT PREVENTION where we discuss the basics of preventing basement or crawl space water entry, report a foundation collapse case study, and describe some simple steps that may cure a wet basement without major expense.

Moisture from a wet building basement or crawl space travels up through the building where it can often condense in an attic, causing mold, frost, and even rot in a building if proper under-roof ventilation is missing. In the case of this home, we also need to correct the cause of basement water entry - in this case almost certainly it's a roof spillage or gutter problem since we see water stains so high on the foundation walls.

© Copyright 2009 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 Basement for Sources of Building Moisture Appearing as Attic Condensation

Photo of a wet basement masonry block wall Another important observation about the causes of and cures for attic moisture condensation is that buildings with an attic moisture condensation problem very often have wet basement or crawl space water entry problems. In fact even before entering an attic to inspect for moisture, while still outside I often look at excessively curled asphalt shingle roofs and suspect a basement water entry problem.

In the photograph shown here our client points to moisture stains originating high on a masonry block basement wall. The presence of moisture staining high on the wall confirm that the water source is either roof runoff spillage against the foundation or a surface water runoff problem.

This is not a case of "rising groundwater" or "a buried stream". A careful study of the pattern and location of moisture stains gives important diagnostic information about the probable source of basement water entry and of leaks or building moisture problems in general.

Actual basement flooding or simply high basement moisture forms a moisture source in a building that affects the entire structure. Moist air rises through the building by natural convection, eventually finding its way into the attic or roof cavity. If the roof cavity is not adequately vented, moisture will condense there leading to building damage and perhaps an attic mold problem.

Simply cleaning up or removing attic mold such as moldy roof plywood, framing, or mold contaminated attic insulation may not provide a lasting cure for attic mold. In fact even correcting the inadequate attic venting (as we describe below), will be insufficient if a basement or crawl space source of attic moisture was also present and if it remains un remediated.

List of Basement Water Entry & Moisture Sources

Concrete Foundation Wall Leak Points - Leaks at Cold Pour Joints

Basement water leak at cold pour joint (C) Daniel Friedman Basement water leak at cold pour joint (C) Daniel Friedman

At Cold Pour Joints we discuss the cause and possible significance of cold pour joints on a poured concrete foundation wall. Usually a cold pour joint in a concrete wall is only of cosmetic import. But if sufficient time elapsed between successive concrete pours into an individual foundation wall, the lower wall concrete "sets up" enough that there is a poor bond between that layer and the next pour of concrete into the wall forms.

The result can be not only a visible "crack" in the poured concrete wall, but this cold pour joint may leak surface water or ground water into the building. Our photo (above left) shows white efflorescence stains left by a long history of building foundation leaks at a cold pour joint on this building. Also notice that in the corner there was some efflorescence above the cold pour joint, while at the second photo (above right) there was efflorescence and leakage only below the cold pour joint. At both of these locations a roof drainage downspout had spilled water against the building wall for many years.

Cold pour joint leak evidence (C) Daniel Friedman
Often, including at this building, the leaks at the concrete wall cold pour joint occurred primarily, or in this case only, where there was a concentration of water spillage outside the building. In our two photos above, the two areas of leakage, at the cold pour joint in the building corner, and further along to the right of that corner in a lower cold pour joint leak, you can see that water leakage was concentrated (shown by the white efflorescence on the wall).

Our photo at left shows a closeup of white mineral salts (efflorescence is discussed at Efflorescence & white or brown deposits) left on the concrete foundation wall below a leaky cold pour joint.

So routing downspouts well away from the building and terminating the downspout at a location where water will continue to run away from the building rather than back towards it would probably have prevented most or all of this basement water entry problem as well as the mold contamination that it led to.

Concrete Foundation Leak Points - at Form Ties

Concrete form tie leak (C) Daniel Friedman

Form ties are usually steel wires or rods that secure the front and back foundation wall forms in place during a concrete foundation wall pour. After the wall has cured the ties are cut or broken off.

On (usually rare) occasions we find water leaks through the poured foundation wall at the form ties, as shown by the stains in this photo.

The significant volume of leakage along this basement wall suggests that there was an outdoor problem with surface runoff or mis-handling of roof runoff around the building.

Concrete Foundation Leak Points - at Wall Cracks

Leak at concrete wall crack (C) Daniel Friedman
Our photo (left) shows stains at a poured concrete foundation wall crack that had been covered by insulation, drywall, and paneling in a finished basement.

Episodic water leaks through this crack sent water into the wall cavity and below a raised floor in the basement where it was un-noticed until a severe rainfall and leak quantity brought enough water into the basement for water to appear above the finished floor level.

The exact location of the leak was apparent once we removed the basement wall and floor coverings - a step that was necessitated by a mold-contamination problem that originated in basement water leakage.

Concrete Foundation Leak Points - at Floor Slab Shrinkage Gaps

Leak at floor slab to wall opening (C) Daniel Friedman

Our photo (left) shows a normal concrete floor slab shrinkage gap where the floor (under our pen) abuts a poured concrete foundation wall.

The brown material on the floor is mud which we suspect rose up from below the slab when surface runoff or ground water saturated the soils around and under the floor slab.

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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
AIR BYPASS LEAKS
AIR LEAK DETECTION TOOLS
AIR LEAK MINIMIZATION
AIR SEALING STRATEGIES
BATHROOM VENTILATION
  BASEMENT WATERPROOFING
    BASEMENT DE-WATERING SYSTEMS
    EXTERIOR WATER SOURCE ELIMINATION
    FOUNDATION DRAINS & FRENCH DRAINS
    FOUNDATION WATERPROOFING
    GEOTEXTILES & DRAINAGE MATS
    SEALERS, Basement Floor & Wall Moisture
    SITE DRAINAGE
    SUMP PUMPS GUIDE
    WINDOW LEAKS INTO BASEMENT
BLOWER DOORS & AIR INFILTRATION
BRICK LINED WALLS
BUCKLED FOUNDATIONS due to INSULATION?
CATHEDRAL CEILING INSULATION
FREEZE-PROOF A BUILDING
ATTIC CONDENSATION CAUSE & CURE
Air Bypass Leaks, Thermal Tracking
Blocked Soffit Intake Vents
CATHEDRAL CEILING INSULATION
Comparing Two Houses
Heat Tapes: Use on Roofs for Ice
HEAT LOSS: How to Calculate Heat Loss in a Building
HOUSEWRAP AIR & VAPOR BARRIERS
HUMIDITY LEVEL TARGET
ICE DAM PREVENTION
INSULATION INSPECTION & IMPROVEMENT
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
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
HEAT LOSS: How to Calculate Heat Loss in a Building
HOUSEWRAP AIR & VAPOR BARRIERS
HUMIDITY LEVEL TARGET
ICE DAM PREVENTION
INSULATION INSPECTION & IMPROVEMENT
MOISTURE CONTROL in BUILDINGS
THERMAL TRACKING & HEAT LOSS

  • 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 11/06 & 12/08
  • John Annunziata, P.E. - NY Metro ASHI during informal chapter discussions about roof and attic ventilation options (1986-1996).

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

  • Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
  • ...
INTERIORS of BUILDINGS
INSULATION INSPECTION & IMPROVEMENT
MOISTURE CONTROL in BUILDINGS

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More Information on 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:

InspectAPedia.comInspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.
GO TO the MOLD and INDOOR ENVIRONMENT INFORMATION CENTER for in-depth advice on avoiding testing for or cleaning up mold and other indoor environmental hazards, odors, gases, contaminants
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
GO TO MOLD TEST KITS: This expert-recommended mold test kit is cheap and yet top performing *IF* you use a competent analysis laboratory!
Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab
GO TO IAQ/MOLD-TEST LAB SERVICES: Mold, Pollen, indoor air quality, field and laboratory services by an expert.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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09/27/2009 - 06/02/1990 - InspectAPedia.com/interiors/Basement_Water.htm - © 2009 - 1988 Copyright Daniel Friedman All Rights Reserved - InspectAPedia® is a Registered U.S. Trademark