Mold Inspection and Testing in Portland, OR: Finding the Moisture Behind the Mold

Signs a mold inspection is worth scheduling

Visible mold is the obvious reason and rarely the only one. These are the situations where an inspection earns its cost.

• A musty smell with no visible source, strongest near floor vents, in a closet on an exterior wall, or when the heat first comes on.
• A leak, flood, or sewer backup in the past that was dried but never checked afterward.
• Stains, bubbling paint, peeling wallpaper, or warped baseboards on a wall or ceiling.
• Floors that cup, buckle, or feel damp and cold, which can mean moisture is coming from below.
• Window condensation all winter, or a humidity gauge that stays high for weeks. Our water damage page gives the humidity targets.
• A home purchase where the crawl space or attic cannot be seen, or a sale after a water event.
• A tenant complaint, a lender's request, or an insurance adjuster asking for documentation.
• A stuffy nose, coughing or wheezing, or burning eyes that ease when you are away from the building. The CDC lists these among the ways mold can affect some people. They have many other causes, so an inspection examines the building and does not try to diagnose the occupant.

A mold inspection and a mold test are different things

A mold inspection is an assessment of a building's moisture and any visible or suspected growth: where water enters, where it travels, and what materials it has reached. A mold test is one tool an inspection may use, which means a sample sent to a laboratory. Many people ask for the test and need the inspection. A lab report can say which spores were collected at one spot on one day. It cannot say where the leak is.

Federal guidance points the same way. OSHA's bulletin on mold in the workplace says that "in most cases, if visible mold growth is present, sampling is unnecessary," and that "the underlying cause of water accumulation must be rectified or the mold growth will reoccur." The CDC says it does not recommend mold testing, and NIOSH states that there are no health-based standards for mold or other biological agents in indoor air.

Credentials vary, so they are worth asking about. The Council-certified Microbial Investigator designation from the American Council for Accredited Certification, for example, requires verifiable field experience in microbial sampling and a passing exam, and the council says holders can perform mold inspection and testing, interpret lab results, and perform post-remediation sampling. The questions at the end of this page include which credentials an inspector holds and whether the inspection stands apart from any repair work.

Do home inspectors check for mold in Oregon?

Not as a standard part of the job. Oregon's rules for certified home inspectors (OAR chapter 812, division 8) describe inspections as visual and not technically exhaustive. They list things an inspector is not required to do, including determining the presence or absence of any suspected adverse environmental condition or hazardous substance, identifying odors or their source, and disturbing insulation to see behind it.

The same rules do require the inspector to enter underfloor crawl spaces, basements, and attics when access is safe, and to report signs of abnormal or harmful water penetration into the building or abnormal or harmful condensation on building components. A home inspector who sees a stain or a damp crawl space will usually flag it. A mold inspection then picks up where the home inspection stops, by finding out where the water is coming from and how far it has gone.

What happens during a mold inspection

The order shifts with the building, and the logic stays the same: gather the history, find the water, document its extent, and decide whether a sample would add anything.

1. 1

   History interview

   Questions about past leaks, floods, repairs, roof and plumbing work, and when the odor appears: after rain, in midwinter, when the furnace starts. Timing narrows the source before any instrument comes out.

2. 2

   Exterior first

   Roof edges, gutters and downspout discharge, grading along the foundation, window and door flashing, and where dryer and fan ducts end. Water that reaches the inside of a house arrives from the roof, from the ground, or from plumbing, and a walk around the outside shows which of the three is plausible. The gutters and drainage page covers what is found there.

3. 3

   Interior survey

   Every room, including closets on exterior walls, cabinets under sinks, behind toilets, around tubs and window sills, ceilings below bathrooms, and the base of walls. The inspector looks for staining, bubbling, efflorescence, cupped flooring, and odor patterns.

4. 4

   Moisture mapping

   Readings are taken across a grid on suspect walls, ceilings, and floors and recorded, so the wet area has a boundary on paper. A map is also what makes a later re-check meaningful.

5. 5

   Attic and crawl space

   Entered when it is safe and accessible. The inspector checks sheathing and framing, insulation, duct terminations, the ground cover, and standing water. See attic mold and crawl space and subfloor mold for what those spaces reveal.

6. 6

   Looking behind surfaces

   A borescope through a small hole, an access panel, or an outlet cover. New York City's health department guidance notes that a boroscope or a moisture meter may be helpful in identifying hidden sources of fungal growth and the extent of water damage. A small inspection opening in drywall is made only with the owner's permission.

7. 7

   The sampling decision

   The inspector decides whether any lab sample would change what happens next, and if so which type and where. Often the answer is no, and the report says why.

8. 8

   Written findings

   A report with the moisture map, photographs, locations, suspected sources, recommendations in order of priority, and a list of areas that could not be reached.

Moisture instruments: what each tells you, and where each misleads

Instruments measure moisture and temperature. None of them measures mold, and each has blind spots, which is why an inspector uses several and cross-checks.

Sample types and what each can show

Spore trap (air sample)

Air is drawn through a cassette for a set time and a lab counts what was collected. It shows what was in the air at that place and moment, which shifts with weather, activity, and ventilation. New York City's guidance says air sampling should not be part of a routine assessment, because remediation decisions can usually be made on the basis of a visual inspection and some air-sampling methods are prone to false negatives.

Surface sample (tape lift or swab)

A strip of clear tape or a sterile swab picks up material from one surface. It helps when the identity of a stain is unclear, because it can confirm or rule out mold at that spot. It says nothing about the rest of the room. The same guidance describes surface sampling as less destructive than bulk sampling.

Bulk sample

A small piece of material is cut out or scraped into a clean bag and sent to the lab. It is the most direct way to check a hidden or suspect material, and it leaves a small repair.

Culture

Material is grown on a medium so organisms can be identified to genus or species. Only organisms that are alive and grow in the lab appear, so a culture result and a spore count answer different questions.

Outdoor control

Air results mean little without a sample taken outdoors at the same time. The New York City guidance says outdoor samples should be collected concurrently, and that air samples should be evaluated by comparison of indoors to outdoors and by fungal type.

Laboratory accreditation

The American Industrial Hygiene Association accredits microbiology laboratories through its Environmental Microbiology Laboratory Accreditation Program. Accredited laboratories take part in quarterly proficiency testing. AIHA publishes the list of accredited laboratories, and the lab named in a report can be checked there.

What a lab report can and cannot tell you

A report lists the organisms found and their counts. It does not say whether the building is safe, because no number exists to compare it to. OSHA's bulletin states that there are no federal standards or recommendations from OSHA, NIOSH, or the EPA for airborne concentrations of mold or mold spores. NIOSH adds that short-term spore counts cannot be interpreted in relation to health risks.

What a report can do is support a comparison. According to the New York City guidance, a few or trace amounts of spores in a surface or bulk sample should be considered background, while larger amounts or fungal fragments such as hyphae may suggest growth at or near the sampled spot. For air, the useful signals are fungal types that are present indoors and scarce outdoors, and indoor counts that are much higher than the outdoor sample taken at the same time. Even then the answer is a pointer. The moisture map decides where to look and what to open.

The CDC puts the practical conclusion bluntly: you cannot rely on sampling and culturing to know whether someone might become sick. If mold is visible or the moisture is documented, the work moves ahead from there.

A mold inspection before you buy or sell a home in Oregon

Oregon's seller's property disclosure statement, the form in ORS 105.464, asks sellers about moisture directly. It asks whether there are any moisture problems, areas of water penetration, or mildew odors, especially in the basement, and whether the property has been tested or treated for items that include mold. The form also tells the buyer to obtain and pay for the services of a qualified specialist to inspect the property. Sellers answer from what they know, so a buyer who learns of a water event can ask for the repair records and a written inspection of the affected area.

For buyers, the practical points are access and timing. Ask early that the crawl space hatch and attic opening be cleared, because an inspector who cannot see a space reports that it could not be reached, and a report with large gaps does not settle much. A mold inspection is also a snapshot: it describes the building on the day it is done, which is a reason to ask when water events occurred and what was done about them.

For sellers, a documented repair is stronger than a statement that a problem was fixed. A written moisture map, photographs of the repair, and a post-remediation verification give a buyer something to read. Questions about the disclosure form itself belong with a real estate attorney or the listing broker.

What affects the price of a mold inspection

The price follows the work involved. No two houses cost the same to assess, and a written estimate before the visit should say which of the following it includes.

• Size and layout More rooms, more levels, and more wall area mean more readings to take and more to map.
• Access Attic hatches, crawl space entries, finished ceilings, and stored belongings add time, and entering an attic or crawl space needs protective gear and a clear path.
• Samples Each sample carries a laboratory fee, air samples need an outdoor control, and a faster turnaround from the lab costs more.
• Depth of mapping A handful of spot readings is quicker than a documented grid, a thermal survey, and borescope work.
• Report detail A findings summary and a photo-documented report with a written scope for repair are different products.
• Follow-up A second visit to re-check readings after a repair or a dry-down is a separate trip.

If a covered water event is involved, ask your insurer whether the policy pays to locate the source of the leak or to confirm the extent of the damage, and send the written report with the claim. Where there is no covered event, the inspection is generally paid by whoever orders it. Our report is written so that an adjuster, a lender, or a contractor can use it, with moisture readings, photographs, locations, and the suspected source.

Questions to ask any mold inspector

These questions work for any company, ours included.

1. Do you also sell remediation? If so, will the inspection be a separate written scope that I can take to another contractor?
2. Which instruments will you use, and what will you do when the readings are unclear?
3. In what situations would you take a sample in my house, and in what situations would you not?
4. Which laboratory will you use, and is it accredited for fungal analysis?
5. Will an outdoor sample be taken at the same time as any air sample?
6. What credentials do you hold, and how much of your work has been in attics and crawl spaces?
7. What will the report contain, and when will I have it?
8. What happens with areas you cannot reach?
9. What is not included in the price you quoted?

Frequently asked questions

Sources

• OSHA, A Brief Guide to Mold in the Workplace (SHIB 03-10-10)
• CDC, About Mold and Your Health
• CDC NIOSH, Mold, Testing, and Remediation
• New York City Department of Health and Mental Hygiene, Guidelines on Assessment and Remediation of Fungi in Indoor Environments (2008; copy hosted by the City of Toronto)
• Oregon Construction Contractors Board, Home Inspection Standards (OAR chapter 812, division 8)
• Oregon Revised Statutes 105.464, seller's property disclosure statement
• USDA Forest Products Laboratory, R. M. Rowell, Moisture Properties (meter reliability and wood moisture)
• Fluke, Moisture detection with thermal imaging
• American Council for Accredited Certification, Council-certified Microbial Investigator
• AIHA Laboratory Accreditation Programs, accredited laboratory directory

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