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Carpet Test for Mold: How to Collect Test Samples from Carpets & Soft Surfaces InteriorAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

• How to Collect Indoor Mold, Allergens, Dust, Debris, or Stain Particles from Carpets or Other Soft Surfaces for Microscopic Lab Analysis
• What causes those dark stains on building interior walls, ceilings, floors, or carpets when the stain pattern appears not due to thermal tracking?
• A Photographic Guide to Diagnosing Indoor Stains on Carpet, Cabinet Doors, HVAC Registers
• An investigation strategy for indoor stain diagnosis, cause, cure, removal, & prevention

This article describes & how to collect mold, allergen, or other particle or mold test samples from carpets, furniture, drapes, or other soft surfaces to aid in the diagnosis of the cause of interior wall, ceiling, flooring or carpeting stains and explains how to recognize their probable cause and source, including soot stains, house dust stains, pet or animal stains, and thermal tracking or thermal bridging stains associated with building air leaks, and building insulation defects.
Often these stains are mistaken for toxic indoor mold. When investigating a building for a mold problem, you can save mold test costs by learning how to recognize Stuff that is Not Mold or is only Harmless Mold but may be mistaken for more serious contamination - save your money. Because some clients have on occasion sent samples to our mold test lab that really should not have been collected, much less looked-at, we provide this library of photographs of things that are "not mold" and don't need to be tested. These are substances that you can easily learn to recognize in buildings.
Save your mold test money, and increase the accuracy of your mold contamination inspection or test for toxic or allergenic mold in buildings: review these items to learn recognize non-fungal materials or even possibly harmless cosmetic "black mold" often mistaken for "toxic fungal growth."
Also see Carpeting odors: diagnose & cure carpet smells due to mold, mildew, pet urine, and carpet stains - thermal tracking, and carpet testing advice. © Copyright 2008 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.

How to Collect Indoor Mold, Allergens, Dust, Debris, or Stain Particles from Carpets or Other Soft Surfaces for Microscopic Lab Analysis

How to Collect Tape Samples of Stains, Dust, or Debris on Hard Surfaces or Surfaces with Visible Mold

For particles or stains found on hard surfaces indoors such as walls, ceilings, or furniture, or where mold growth is visible on any surface including carpeting or furniture, often a simple adhesive tape sample will perform well. Furthermore, this sampling procedure is itself diagnostic, since if the adhesive tape is unable to lift and collect any particles from the surface, that also tells us something about the type of staining present. But remember that even an apparently "clear" tape sample (when viewed by the naked eye) may contain important diagnostic particles which will be quite evident when viewed as a properly prepared microscopic sample and at proper magnification and lighting in a forensic microscope.

Caution: Surface samples of mold growth on a soft material such as floor carpets or upholstered furniture may identify what is growing on the surface but it may fail to identify what is growing inside the same material if a different mold genera or species is present in that location.

See Six Easy Steps to Get and Mail a Mold Test Kit to Our Lab for 24-Hour Analysis and Report for a surface sampling procedure using adhesive tape. You can use this sampling method to collect surface particles for submission to any qualified forensic laboratory not just ours.

Qualitative Analysis (what particle types dominate a sample) of Carpet Dust Samples

We use an air-sampling cassette connected to a vacuum pump to collect debris from carpets, upholstered furniture, or carpets. In the hands of an experienced investigator a useful non-quantitative analysis can be performed to collect particles which, examined in the lab, can tell us the dominant particles present in the debris.

The lab should also be asked to cite other particles, even occurring at low levels, if the particle type is particularly diagnostic of a potential indoor air quality problem. An example is the presence of chains of Penicillium/Aspergillus mold spores since when found occurring in chains, these spores are suggestive of a nearby (potentially toxic or allergenic) mold contamination problem.

What is the Consistency of the Vacuum Method for Testing Carpets, Couches, Curtains, or Other Surfaces for Mold or Other Particles?

As you can see in the photograph of sampling cassettes above, we may use a template to define a four square inch area to be vacuumed. While it is a simple matter to define a consistent area size when using vacuum methods to test soft surfaces such as carpets or couches, it is very very difficult to actually sample these surfaces in a manner which is quantitatively consistent from sample to sample. While some independent studies have attempted to explore this question by "seeding" a carpet surface with a known quantity of particles, we are very doubtful of the conclusions by some investigators if they assert that sampling consistency can be achieved. Where sampling consistency cannot be achieved, the quantitative comparison of samples from different areas is a tricky business, and except for findings of the presence or absence of high levels or dominant-particle levels of certain particles in a carpet vacuum sample, our view is that more detailed findings should be viewed with caution.

Here are some sources of inconsistency in vacuum sampling of soft surfaces:

• Sample location Debris level: Variation in the amount of soil, debris, or particles in different locations on the surface to be sampled. Two successive vacuum samples of the very same spot are likely to produce different results since each sampling removes some particles. Two vacuum samples of nearby spots on a carpet may produce different results because of variations in the level of debris by area.
• Sampling Location Traffic or Cleaning Level: Vacuum sampling of a high traffic area of a carpet or vacuuming an area of carpeting which is easily reached during regular or special carpet cleaning processes may produce a very different result than a vacuum sample collected from an area exposed to (or not exposed) to settling particles, mold growth, variations in moisture level, or ease of access for ordinary cleaning
• Pile depth: Variations in pile depth of carpets or other fabric surfaces
• Moisture Levels: Variations in moisture exposure of different areas of carpeting which is suspected of mold contamination
• Particle collection efficiency: the percentage of particles captured by adhesive type sampling cassettes varies by particle size and velocity; if the sampler is not designed for collection of the particles of interest, or as is very common with vacuum samples of surfaces containing a high level of debris, if the adhesive surface becomes blocked by particles, subsequent material entering the sampler is lost, making any quantitative analysis questionable.
• Sample area size: Variations in sampling area size
• Vacuum strength: Variation in the vacuum strength of the sampling pump itself. Especially if a battery-operated pump is used, the pump strength may vary during use as battery level declines.

High Efficiency Vacuum Sampling Methods for Carpets or Other Surfaces

Other vacuum methods which use a calibrated flow rate and a sampling filter can collect nearly 100% of the particles from a surface, permitting a quantitative analysis of the number of particles per square inch. In our OPINION this is often a rather questionable procedure. Even studies which claim to report that the results of this sampling method are repeatable (a measure of sampling method reliability) we find that there is an enormous variation, probably several orders of magnitude, in the number and possibly even the type of particles collected in such samples depending on the investigator's choice of sampling location, sample duration, vacuum strength, and other factors.

The result may be an analysis which is impressive in its precision, say giving 1,243.275 particles of particle type X per square inch of surface, but completely inaccurate (because there maybe so much variability due to sampling procedure that sampling an area one foot away gives a particle level of 124,327.5 particles per square inch.).

See PHOTO GUIDE TO STAINS on Indoor Surfaces for examples of some common types of indoor stains on HVAC registers, doors, carpets.

Usually soot marks, thermal bridging, or thermal tracking stains appear, if at all, in the building interior locations listed just below discussed in the remaining sections of this article.

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.

Technical Reviewers

Particular thanks are due to experts and also consumers who read these articles and suggest corrections, changes, and additions to the material. Content suggestions, technical corrections and content critique are invited for any of the content at our website.

• Daniel Friedman - InspectAPedia.com ^TM Website Author/Editor
• Thanks to Alan Carson, Carson Dunlop, Associates, Toronto, for technical critique and content suggestions regarding thermal tracking.
• Critique, contributions wanted: Contact Us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

More Information on Finding and Identifying Mold in Buildings and Building Diagnostic Inspections and Repairs

• Attic Condensation and Ice Dam Leaks - Detection and Correcting Venting and Condensation Problems in Buildings
• Insulation Inspections: Insulation in Buildings: Identification, R-values, Heat loss, Insulation Types, Insulation Characteristics
• Asbestos pipe insulation in buildings
• Brick "Insulation" in Building Walls
• Heat Loss Calculations, Insulation Properties, Definitions of R, K, U values, Insulation Design
• How to Detect and Correct Attic Condensation & Prevent Ice Dam Leaks in Buildings
• Insulation Materials as Indicators of Building Age
• Indoor Air Quality Investigations: Fiberglass in Indoor Air, HVAC ducts, and Building Insulation
• Insulation Identification Photographs - Fiberglass insulation photos, yellow, pink, green, white fiberglass identification in building attics, walls, ducts, other locations
• Insulation Identification Photographs - Cellulose insulation photos, Mineral wool insulation photos, rock wool insulation photos, cotton insulation photos, balsam wool insulation photos
• Insulation Identification Photographs - Vermiculite insulation photos
• Insulation Properties, Table of R-Values, density, moisture permeability, fire safety, aging effects on various insulation materials
• Mold in Fiberglass in Insulation
• Radiant Heat Floor Mistakes to Avoid case history of improper placement of slab insulation and radiant heat tubing
• Thermal Trackingthermal bridging & air leak stains in buildings or on building insulation
• Un-Vented Roof Solutions - How to Prevent Attic Condensation, Ice Dam Leaks, Roof Mold, & Roof Structural Damage in Buildings with Un-vented Roof Cavities
• Vermiculite Building Insulation & Asbestos
• Ice Dam Leaks in building attics and roof cavities, how to inspect for evidence of leaks, identify causes, and correct bad attic ventilation, improper roof venting, and these causes of attic mold or roof structure damage
• Looking for Mold what mold is often found where in buildings - simple technical presentation
• Mold spores in the Home - a Photo ID Library for detection and identification of mold allergens
• Recognizing Allergens: What various indoor allergens look like - identification photos to help identify pollen, dust mites, animal dander, toxic or allergenic mold - Common Mold and other Allergens, Irritants, Remedies & Advice
• Stuff that is not mold but is often mistaken for it - things you may not want to test. Also, not all "black mold" is toxic - here are examples of harmless black mold.
• Animal Allergens: Dog, Cat, and Other Animal Dander - Cleanup & Prevention Information for Asthmatics and regarding Indoor Air Quality.

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

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

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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