Photograph: Mold under carpeting on tack strips indicate history of water entry, suspect moldy carpet - Daniel Friedman A Home Buyer's Guide to Mold Inspection & Testing

  • HOME BUYERS' GUIDE to MOLD INSPECTIONS - CONTENTS: when, where, why & how should a home buyer look for or test for mold contamination in a home being purchased? How to look for mold in buildings. Where to look, where to collect mold samples. Mold sampling mistakes to avoid. What mold looks like in different areas or on different surfaces
  • POST a QUESTION or READ FAQs about how to screen a building for expensive or dangerous mold contamination

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Mold inspecting or testing advice for home buyers:

This article gives advice to home buyers concerned about inspecting and testing for mold in a building to be purchased but where there is not already a known mold problem.This website describes when and how to find mold and test for mold in buildings and how to correct mold problems.

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Mold Inspection and Testing Advice for Home Buyers

Because it is perfectly normal to find some mold spores in air everywhere and because mold is ubiquitous in the environment, it makes no sense to attempt to buy a "mold free" home, nor should your objective be to test a prospective new home to be sure that there is no mold therein.

You can't eliminate mold in the environment indoors nor outside. If you could we'd all be in trouble as nothing would ever decay and we'd all be so buried in junk and debris that nothing could grow on the earth.

But we don't much like to see growing mold contamination on surfaces or materials indoors and certainly not on our walls, ceilings, or furniture. There we remove it or clean it off. Because there are potential health risks involved, especially for some people, and because there are significant costs involved in large mold remediation projects, home buyers often contact us to ask about testing a home for mold during the home buying process.

A thorough building investigation for problematic mold needs to address hidden mold reservoirs, for which our approach is to complete a detailed inspection and building (leak) history as well as to record occupant observations and complaints.

A low-cost superficial test or superficial "quick look" for problem mold (such as an "air test for mold", a "home test kit for mold" or a "mold culture test") is likely be a waste of money since those approaches to screening a building for mold contamination are unreliable. Certainly if problem mold is visible that's unambiguous. But superficial visual inspections and grab-tests for mold in air or on surfaces, performed without being accompanied by a very thorough building inspection, history taking, and occupant interview, have a high risk of missing important reservoirs of problem mold in a building.

Some "mold inspectors" may charge as much as a true expert to examine your building ($750 to $2000) but in fact may be doing little more than a quick inspection for visible mold and a few superficial tests. This is also an unreliable approach.

Since water and moisture are gating factors for indoor mold contamination I recommend that you start with a thorough inspection of the building for conditions likely to produce a mold problem - leaks, moisture traps, bad ventilation, history of flooding, etc.

Why Can't I Just Collect a Mold Sample and Based on That, Decide if the House We're Buying Has a Mold Problem or Not?

Question: Quick Lab Turnaround on Mold Tests

Dear Lab Director:

We desperately need the results of the mold sample we collected yesterday ASAP. We cannot proceed with the closing process until we have these results, and our house purchase closing is scheduled for Friday. - Worried in Po-Town.

Reply: Don't Decide to Buy or Not Buy a Home Based on a "Mold Test"

Dear Worried:

While most mold test labs and forensic laboratories can provide very fast mold sample analysis - 24-hours or less after a sample is received, a home buyer who is worried about a possible costly mold contamination problem in a building should certainly not be deciding to go ahead with the sale or not simply based on a "mold test".

This is even more true if the mold test or mold sample was collected by someone who is not an expert.

If there is a reason to be worried that there is a significant mold problem in a building, and if you have not had an expert perform a very thorough, visual inspection, even the most technically proficient "test", alone, is unreliable.

A mold test, even a good one, is a screen that might detect evidence of an indoor mold problem.

But absence of evidence of mold in a building is not, unless accompanied by an appropriate, expert, onsite investigation, never evidence of absence of a mold problem.

If you have a particular concern about the building, and regardless of the outcome of the lab work, we recommend that you discuss this with your attorney, your realtor, and your home inspector. Your attorney may recommend that you either delay the closing, or if agreeable to the seller, obtain some estimates to establish a "worst case" guess of possible mold remediation cost and escrow that amount long enough to give yourselves time for an expert assessment.

Does this mean every home should be inspected and tested by an expert to look for mold?

Of course not. At MOLD / ENVIRONMENTAL EXPERT, HIRE ? we discuss some criteria that help decide if it is appropriate to bring in a mold expert, such as pre-existing evidence of a problem: large areas of visible mold, evidence of or an historical report of building flooding, significant plumbing leaks, or other leaks, etc.

Why to Hire a Good Home Inspector for a Preliminary Check for Mold-Producing Conditions in a Building

If your "mold inspector" is simply going to enter the building, collect a few air, surface, or culture samples, and perhaps report on obvious visible mold in the living space, you're not receiving a very professional nor very reliable service.

An experienced, thorough, detailed, qualified home inspector will be much better at recognizing those (mold-conducive) conditions than a typical "mold inspector" or a typical industrial hygienist who does not know building science and who lacks experience in identifying where and why mold problems occur in buildings.

Home inspection standards, training, and experience teach inspectors where water, leaks, and moisture problems occur in buildings. Here are some examples of water or leak history problems that can create a hidden mold problem in a building:

  • A one-time basement flood due to a burst pipe, sewer backup, or area flooding - the basement may now look clean and dry but significant mold contamination may be present in basement walls, under carpeted floors, or in building insulation
  • An older home with poor under-roof ventilation may have experienced condensation and moisture-related mold contamination of the attic insulation, roof sheathing, or hidden side of ceiling drywall; in northern climates such a home may have had ice dam leaks into wall cavities, producing hidden mold in building walls.
  • A home where plumbing leaks from an overflowing bath tub, leaky fixture traps, or supply piping leaks may have had leaks into wall and ceiling or floor cavities, leading to hidden mold contamination
  • A home with a history of recurrent a damp or wet crawl space is at extra risk of moldy crawl space insulation, producing mold species whose spores move upwards into the occupied space by riding normal air leaks and air convection currents.

A home inspector is expected to recognize these leak and moisture problems even though s/he is not performing an environmental inspection.

Also see MOLD TESTING by HOME INSPECTORS? for an opinion-text on the marketing of mold tests as a revenue source for home inspectors.

A Home Inspection is not an Environmental Survey of a Building

Unless the inspector happens also to be trained in mycology, forensic microscopy, and aerobiology, s/he will be focused on the condition of the building, not just on the presence of mold, but such a person is the best expert to identify leaks and moisture problems among other building risks.

Don't try to force the inspector to give an environmental report - it's outside the scope of a home inspection.

But do ask the inspector to be extra thorough and detailed about leaks, moisture, ventilation defects. And of course any conscientious and respectable inspector will also tell you if s/he happens to also actually see mold (or other out-of-scope hazards) during the inspection.

Key Mold Contamination Articles for Home Buyers

  • ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD describes what to do if problem mold is found in a building
  • HIDDEN MOLD describes methods used to find hidden mold in buildings
  • MOLD DETECTION & INSPECTION GUIDE describes how to look for mold in buildings
  • MOLD / ENVIRONMENTAL EXPERT, HIRE ? contains advice on when to hire a mold consultant to inspect and test a building. We identify factors such as the presence of people at extra medical risk (asthmatics, immune-impaired, infants) and leak history that increase the risk of a significant mold problem or that otherwise justify the expense of a thorough building survey for mold contamination.
  • MOLD CLEARANCE INSPECTIONS describes post remediation mold clearance inspection and test procedures, which could form a reasonable mold-screening inspection and test for a building
  • MOLD LEVEL REPORTING - what levels of mold should be reported and how: do very precise numbers mean that the mold test was at all accurate? (No.)
  • MOLD TEST KITS describes simple low-cost methods to screen building surfaces or building dust samples for problem mold
  • MOLD REPORTS describe what should be found in a usable and competent mold test and inspection report
  • WHAT MOLD LOOKS LIKE provides a photo library that helps anyone recognize mold on building surfaces and includes links to articles describing materials that are not mold but may indicate moisture problems that increase mold risk, as well as links to articles describing other non-moldy stuff often mistaken for mold



Continue reading at WHAT MOLD LOOKS LIKE or select a topic from the More Reading links shown below.

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HOME BUYERS' GUIDE to MOLD INSPECTIONS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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