MOISTURE & MOLD INSPECTIONS
• Purpose: to find signs of water damage or mold growth, to guess possible sources/causes, to decide if it’s a past problem, or significant, active, and increasing.
COMMON PROBLEMS
- Moldy subroof under sheathing, often on large areas, from moisture condensation.
• Moldy, water stained insulation below leaks.
LOOK FOR MOLD GROWTH
• Look in damp locations.
• Look for the circular spots that colonies form initially, or the eventual fuzzy mats that form as the spots merge.
- Look also for stringy white or brown mats of wood rot fungus.
- Note the mold colors: often black, or white, olive, green, brown, gray, pink (bathrooms), orange. Many turn brown or black when old.
- Be aware that dark stains leached out of wet wood are not mold, but do indicate conducive conditions, so might also include mold. These often need to be tested.
• More mold grows on the N side (away from the sun, so cooler, more condensation), or in the NE corner near Puget Sound (away from the prevailing SW winds).
MOLD APPEARANCE
• Mold growth might be seen after a few days as spots, then as fuzzy growth.
• Wood rot fungus often has stringy white or brown mats on the surface, and eventually soft wood, sometimes breaking into “brown cubical rot”.
• Mold colors may help identify common types.
• Mold usually has plantlike, segmented, or spore structures under a magnifier.
OTHER SURFACE DEPOSITS (NOT MOLD)
• Dark stains leached out of wet wood are not mold, but might also include mold.
• Frosty white, granular, even deposits of wood resins on the surface, following wood grain pattern, driven out of the wood by heat; the sticky pitch then crystallizes.
LOOK FOR SIGNS OF DAMPNESS
• Damp or wet or new materials.
• Moisture condensation on cold surfaces in contact with warm, moist air.
• Water stains or rust or white “efflorescence” salt crystals deposited on masonry.
FIND THE MOISTURE SOURCES
• Roof leaks.
• Humidity from air rising, from people breathing (mostly).
• New building materials such as concrete, lumber, or paint.
• Bathroom or kitchen exhaust fans vented into the attic space.
LOOK IN COMMON PROBLEM AREAS
• Upwind (S & W walls near Puget Sound) from rain leaks.
• Cooler N sides, from condensation.
LOOK FOR OTHER CONDUCIVE CONDITIONS
• Inadequate ventilation to dump excess moisture.
• Inadequate roof drainage: gutters, downspouts, drain fields.
CONDUCIVE CONDITIONS
We must avoid conditions conducive to moisture, surface molds, or WDOs, such as:
• Damp or wet or new materials.
• Moisture condensation on cold surfaces in contact with warm, moist air.
MOISTURE TESTING
• Measure moisture within building materials using conductivity meters:
1. Pin-type meters that poke needles either millimeters (for surfaces) or inches (for underlayers) into the material.
2. Pad-type survey meters that send radio waves through the material:
a. regular shallow (a couple inches) meters to check just under the surface, or
b. deep (several inches) “wet-wall” meters to check across insulation or a wall cavity.
MOLD TESTING ONSITE
• Rub a finger across a black surface to see if it’s soot (greasy stain on finger).
• Wet a small area with bleach to see if the color disappears, like mold does.
• Look at an uncertain area under a magnifier to see if it has any plantlike structures.
MOLD TESTING
We test to confirm some hypotheses we have guessed after inspection.
• Mold odor can indicate the presence of hidden damp growth.
• Test the growth to confirm it is mold, if it is uncertain (stain?).
CAUTIONS
• Be aware that disturbing dry mold can release much of it into the breathing air.
• Remember that glass fibers fill the air in most attics. So:
• Wear an air purifying respirator with a HEPA filter cartridge. The best is a powered air purifying respirator (PAPR) supplying air into a helmet & face shield.
• Wash attic inspection clothing often, separately.
Blue Sky Testing LLC 