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MOLD: A COMPLETE GUIDE to TEST CLEAN PREVENT
AIR CLEANER PURIFIER TYPES
AIR FILTERS for HVAC SYSTEMS
AIR POLLUTANTS, COMMON INDOOR
AIR QUALITY IMPROVEMENT STRATEGIES
ALLERGEN TESTS for BUILDINGS
ANIMAL ALLERGENS / PET DANDER
ANIMAL ODORS IN BUILDINGSS
ATTORNEYS and EXPERT WITNESSES
BIBLIOGAPHY ENVIRONMENTAL HEALTH, MOLD, IAQ
CAR MOLD CONTAMINATION
CARPET DUST IDENTIFICATION
CARPET MOLD CONTAMINATION
CAT DANDER in BUILDINGS
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATION or SWEATING PIPES, TANKS
CPSC Indoor Air Pollution Book Online Copy
DUCT SYSTEM & DUCT DEFECTS
EMERGENCY RESPONSE, IAQ, GAS, MOLD
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOODS IN BUILDINGS-mold
GAS EXPOSURE EFFECTS, TOXIC
HUMIDITY CONTROL & TARGETS INDOORS
HOUSE DUST ANALYSIS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
MILDEW REMOVAL & PREVENTION
MOISTURE CONTROL in BUILDINGS
MOLD GROWTH on SURFACES, TABLE OF
MYCOPHOBIA, STAINS MISTAKEN for MOLD
NOISE / SOUND DIAGNOSIS & CURE
ODORS GASES SMELLS, DIAGNOSIS & CURES
OZONE for MOLD OR ODORS
RADON HAZARD TESTS & MITIGATION
SAFETY HAZARDS GUIDE
SICK HOUSE IAQ QUESTIONNAIRE
SMELL PATCH TEST to Track Down Odors
STAIN DIAGNOSIS on BUILDING INTERIORS
VENTILATION in BUILDINGS
Here is an extensive photo guide to mold growing on all kinds of surfaces of all kinds of materials found on or in buildings: What does mold look like growing on various building & other material surfaces? Beginning here is an online reference photo library of various kinds of mold as it is found growing on a wide range of surfaces and materials found on or in buildings. These photos of mold on indoor various materials or "mold growth substrates" may help you recognize mold in buildings, recognize probably-cosmetic mold, and recognize stuff that is not mold and does not need to be tested.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
Directories of 6 atlases or indices of building mold
Catalog of Photographs of Mold Growing on Various Building Surfaces and Materials
Links listed below provide photographs of mold that we have photographed, sampled, and tested on a wide range of surfaces and substances found on building surfaces or on items and contents found in buildings. CONTACT us to submit photographs of mold growth on other manmade or building-related materials.
These photographs, courtesy of Florida home inspector and past ASHI President Mark Cramer illustrates mold growth on an air conditioner air handler. The most common mold genera we find in this location is Cladosporium sp.
You will note that mold growth is present on the air handler insulation, on the metal surfaces of the blower assembly, on refrigerant and condensate piping, and even on the paper labeling on the blower cage. When mold growth is on unpainted metal in an air handler it is most likely dining on organic dust and debris found on those surfaces.
This photograph pair illustrates mold growth on a kitchen range fan hood (below left) and a refrigerator door surface (below right).
Below our pictures show mold growth on plastic controls for a kitchen stove and on the oven door handle, also a plastic component. This home had been subject to flooding that was undiscovered for weeks or longer.
Mold on refrigerator and freezer door gaskets is common, is not likely to be a health concern in a building, should be handled by normal household cleaning, and is not illustrated here.
The photographs below illustrate mold growth on plywood roof sheathing. At left is evidence of a serious roof leak or attic moisture condensation problem (black plywood) and at right a much smaller brown mold growth on the plywood roof sheathing of a newer home. We may find mold growth like that shown at right just above a bathroom ceiling fan that vents directly into the attic space. These molds are very often Aureobasidium pullulans, C. cladosporoides, C. sphaerospermum, or Cladosporium sp. though other dark or brown molds (such as Taeoniella sp.) may be present too. Remember, mold identification by naked eye is unreliable; lab sample analysis is usually necessary.
The photographs below illustrate mold growth on tongue and groove roof sheathing in an attic. These molds are often Aspergillus sp. or Penicillium sp.
Extreme car mold contamination of most of the surfaces inside of the vechile is illustrated by our photo below.
These photographs illustrate mold growth on a woven laundry basket made in Mexico. Damp clothes left in the basket led to mold growth even though the climate itself is a very dry one. (All mold is everywhere all the time). It is also interesting to observe that mold grew more readily on the split (and rough surfaced) side of the reed material used to form the basket.
As you can see we experimented with cleaning this mold using a dilute bleach solution. It was not successful and we decided the best course was to dispose of the basket.
Below our bathroom mold photos illustrate where hidden mold may be found around bath fixture controls, a common point of leakage into the bathroom wall.
Mold on Bathroom Surfaces: bath tile, bath tile grout, shower enclosures
Our photos below show the most common location of mold in tiled bathrooms - in grout or caulk joints. This mold is rarely sufficient to form a health concern, but it might be an indicator of leaks into the bath wall cavity - a greater concern for possible hidden mold and hidden damage. See BATHROOM MOLD for more detail about mold on bathroom surfaces including tile and tile grout.
Below we illustrate other locations where mold may accumulate in bathrooms. In addition to finding mold growth on aluminum surfaces (more likely growth supported by soap scum and skin cells), we have found mold growth on ceramic toilets and sinks (more likely supported by condensation or water splash combined with organic dust or organic waste).
Below our mold pictures show mold growth on books that had been shelved in a library basement in which the relative humidity had not been controlled (below right) and where some books had been wet (below left).
See BOOK MOLD, Moldy Book Cleaning for details about dealing with and restoring moldy books and papers.
Below our photos show mold growth occurring first on the near-horizontal surfaces of wood cabinet doors in a home where flooding had gone undiscovered for several months. We speculate that an extra layer of dust, including grease and organic debris on these surfaces was a factor in the more extensive mold growth on those locations.
But as you can see from our next pair of mold photos, fungal growth can become quite extensive on the smooth vertical sides and faces of kitchen or bathroom cabinets where moisture levels are sufficient.
Mold grows readily on the interior of kitchen and bathroom cabinets as well, as we illustrate below.
Finally, our indoor cabinet mold photos below illustrate why experienced mold remediators and insurance company adjusters assure that cabinets are removed from walls in a home where there has been flooding or leaks from above. The un-coated back side of wall-hung or floor-mounted cabinets are a ready home for hidden mold growth.
It would have been a mistake to leave these cabinets mounted to the wall of the home where they were found, even though mold was not visible on the room side of exposed wall surfaces. And further investigation of the wall cavity behind where these cabinets had been mounted confirmed that the cavity side of the wall needed to be cleaned as well.
Mold growth on cardboard occurs readily in damp or wet areas. Both of the boxes shown in these photos had been located on a wet basement floor.
But the mold on the cardboard box shown below was less obvious. Notice the dark stains and spots along the bottom third of the carton at left ? This photograph illustrates mold growth on a cardboard box in a damp basement not exposed to flooding. In contrast, the box at right has been exposed to flooding.
At CARPET MOLD CONTAMINATION we discuss the detection, importance, and remedy for wet or moldy or smelly wall to wall carpeting and carpet padding.
Below we show two clues that give good evidence of the history of wet or damp floors below carpets - the carpet tack strips. At left are carpet tack strips on a dry floor, and at below right, moldy black carpet tack strips on a floor that has been repeatedly wet. Even a single soaking of wall to wall carpeting will lead to rust stains on the tack strips even if they are not more seriously damaged. .
Below our photos show carpeting that has been repeatedly wet by leaks through the building wall. A closer look showed visible mold on the carpet upper side and even rotted carpet sections. The under-side of this carpeting was a significant mold reservoir in the building.
These photographs illustrates mold growth on suspended ceiling tiles. At left was an extensive Aspergillus sp. mold contamination and at right leak stains and several genera/species of mold on the upper, hidden side of the ceiling tile.
Below are photographs of mold and leak stains on acoustic ceiling tiles. These older ceiling materials happened to also be an asbestos-containing product. Details are at ASBESTOS CEILING TILES, Asbestos-Containing. Also see CEILING FINISHES INTERIOR.
Our photos of the chalkboard in a church basement illustrate use of oblique lighting to show up light colored mold growth that can be difficult to spot. Modern painted surfaces used as chalk boards may support mold growth on both the exposed front and the hidden hardboard back of the unit.
Mold growth in closets and pantries is determined by their materials of construction and of course exposure to leaks (below left) or high moisture or floods (below right).
This leather jacket photograph (below left) illustrates mold growth on articles of clothing - in this case a leather jacket left in a damp area. But we also find mold growth on fabric clothing, both natural fibers and synthetics, depending on the exposure conditions.
Mold growth is generally associated with organic materials that provide food for the fungi that grow on surfaces. There are however fungi (and algae) that colonize stone and other masonry materials such as a sidewalk (below left). But in buildings where there is fungal growth on a masonry surface, most often we encounter it on painted surfaces and in our OPINION it is the paint that is providing mold food.
Also on occasion we have found mold growth on bare concrete and concrete block where we suspect that the nourishment for the fungal colony was in part formed by organic dust and debris on the surface (dogs in the basement) or by materials carried to the concrete block surface by outside water seepage.
While food products with a very high sugar level are resistant to mold growth, they are not "mold proof" as this case study demonstrated. We left a container of sweetened condensed milk with the can opened but a plastic cover in place for four months. You can see the results below. This mold growth is not peculiar to the individual sweetened condensed milk brand; rather it could happen with any similar product.
Below we include photographs one of several principal molds that were growing on this sweetened condensed milk product surface - Aspergillus sp.
As you can see in our photos below, a plastic laminate countertop may appear to be perfectly clean, but its wooden or composition wood or OSB or chipboard substrate may be a welcome host to mold growth in a wet or flooded home.
Our crawl space mold photo at below-left illustrates Stemonitis sp. growing out of a wet sill plate. We also find this mold growing out of OSB subflooring in structures that have remained wet. At below-right a reader-submitted photo shows 20% moisture (at the time of inspection) and heavy fungal growth on both crawl space framing and the subfloor overhead. We suspect that the moisture level has been even greater than 20% in this area.
At below-left our photo shows common damp crawl space area conditions that produce a brown mold on plywood subfloor. Often this fungus is Aureobasidium pullulans, or a species of Cladosporium. We often find other dark or brown molds such as Taeoniella sp. on plywood subfloors visible from a basement or crawl space where there have been leaks into the floor structure.
The yellow mold shown on wood framing at above-right is often found in older homes that have had a history of wet or damp conditions. When we see yellow surface mold in this pattern we are alert for Meruliporia incrassata in the U.S. or Serpula lacrymans in Europe - house eating fungus. Details are at: Meruliporia Mold Photographs
Below we show mold colonization on a hollow core door we tested in a home where flooding had gone undetected for several months. It is interesting but not really a shock to observe that very different levels and even genera/species of mold might grow on an interior door on different surfaces: the face of the door compared with the edges of the door.
The face of a typical hollow core interior door may be a veneer luan or birch, while the door edges are typically solid soft pine. We suspect that either differences in moisture uptake of the two woods on the different door surfaces, or differences in the wood species, or both, resulted in different levels and types of mold growth.
Below are more examples of mold growth on hollow-core interior doors exposed to high moisture (below left) and extensive leaks from above (below-right).
At below left our photograph illustrates mold growth on a solid interior door - a louvered model. At below right there are at least two genera of mold on the solid wood pine door in our photograph.
The solid wood and glass French Doors illustrated below were observed in a home where basement flooding occurred due to a heating boiler leak. Hot water and even steam rose throughout the home and went unattended for more than a week.
These black mold photos (above) show dense black fungal growth on drywall (black mold on Sheetrock™ type wall surfaces) in areas that had been very wet from chronic leaks or building flooding. The distinct top edge of mold growth shown in our photograph at left are often observed due to a flood water level or even without flooding, the sudden or distinct line where mold growth slows or stops can be due to a discontinuity in the wall material - in this case it was a tape joint in drywall that affected the moisture gradient in the wall and thus the mold growth pattern.
Above we provide a closer look at very thick black mold on the cavity side of drywall found in a wet basement. Mold growth on drywall and often on other surfaces includes a family of circular growth patterns (upper area of photo at above right) until the mold growth has expanded to form a solid black covering (left wall of photo at left and lower wall of black mold in photo at right).
Our photo at above left shows black mold colonies as individual rounded "rings" on the cavity side of drywall on a building crawl area wall. The black mold photo at right shows how dense black mold may be hidden from view behind wall baseboard trim (removed for this picture) in a building that has suffered wet floors.
Here are closeup photographs of black mold on building surfaces to show what mold colonies look like on close inspection in-situ. At left is mold on water stained drywall in a basement utility area. At right are small mold colonies that have appeared on a kitchen ceiling in just a few days after a heating system leak led to high indoor moisture and humidity levels.
Much more closely we can examine an individual black mold colony on a painted drywall ceiling (above left). In the microscope at 1000x we can see individual spores of Stachybotrys chartarum - a well known black mold that is often found on indoor building surfaces.
It is expected to find mold spores in indoor dust samples in most buildings. Typically in a building without an indoor mold reservoir the dust samples reflect spores that are also found in outdoor air. But when we find Pen/Asp spore chains or clusters such as shown in our dust particle photographs below, we suspect that there is a nearby problem mold reservoir in the building.
Both Aspergillus sp. and Penicillium sp. spore chains are fragile enough that they normally break into individual spores quickly as the spores are released from the conidiophore and travel through air. So when we see spores that are still "stuck" together, we figure that the spore source must be close by.
Our moldy wood flooring photo at below-left is a clue that there was a history of leaks at the exterior door. In fact an inspection of the crawl area below this room found extensive rot and mold damage - the mold-stained flooring in this photograph had been re-finished with a clear coating, but the damage continued below.
At below-right is another example of "fixing" a moldy floor by simply coating over the mold with a clear floor re-finishing compound.
At below left the yellow-white mold growing up through the hardwood finished floor is a strong indicator of more significant hidden damage, possibly including Meruliporia incrassata - a source of extensive structural rot in some buildings.
At our picture of moldy flooring at below right we are looking up at the under-side of finish flooring that was installed without a solid subfloor. The blue-green thick mold we sometimes find in this location often is identified in our lab as Trichoderma.
The photos just below illustrate Semonitis sp. fungal growth on a resilient bathroom floor covering contributed to us by an Australian reader. You are looking at the same fungus at two different stages of its growth.
Severe mold contamination on floor joists over a flooding basement is shown in our photographs below.
More moldy floor framing
More moldy floor framing includes an area below a protracted leak (below left) and (most likely) cosmetic mold on new framing lumber waiting for use in a reconstruction job for a building that experienced a fire (below right).
The game table (below left) appeared "clean" to the remediators who left it in a basement during and following a mold remediation job. But a look underneath the table at its unfinished wood surfaces told a different story (below right).
Black mold growth (actually dark brown mold) was not visible on this livingroom couch set until a closer inspection was made.
And a still closer look at this fabric illustrates one component of the reason that it is just about impossible to completely clean mold growth from plush upholstered furnishings. Our second photo (below right) illustrates a dining room chair with dense mold growth on the chair back as well as on the upholstered seat (not visible in our photo). While it is possible to adequately clean mold off of solid wood surfaces, only if this chair were a valuable antique might it be economically justified to have it stripped, cleaned, and re-upholstered.
The wood buffet in our photos below was exposed to extensive mold growth in a home that was flooded and left for several weeks. The removal of surface mold is not difficult but the removal of mold odors (MVOCs) that remain can be quite a challenge.
If furniture like this is to be cleaned and salvaged special attention will be needed in cleaning the hidden and un-coated wood surfaces such as the under-side of drawers and the frame of the unit, and following cleaning those surfaces will best be treated by coating with a clear sealant as well. More likely the unit is beyond successful cleaning.
Black, green, white mold growth on upholstered furniture is obvious in these two photographs, of a mold on a leatherette surface (below left) and on an upholstered chair (below right).
Mold found "growing" on glass is most likely growing on organic deposits that are on the glass surface like the overflows on these wine brewing bottles. We have also observed more serious damage to glass lenses on cameras and binoculars exposed to mold. In that case mold is attacking coatings on the lenses.
At below right (click to enlarge) you can just see white fungal mycelia that permeated this sample of hardboard siding that had been used as wall paneling in a church's damp basement.
Mold on Insulation Kraft Paper Facing
In our photo at below left we see black mold and other mold growths on the kraft paper facing of fiberglass building insulation. Our black mold photo on kraft paper found on a different section of building insulation (below right) illustrates mold colonies that do not always grow in round colonies shown other mold photographs.
At below left our photograph shows mold on the wrap covering fiberglass insulation used on piping.
At below right our photograph of a black streak across a batt of fiberglass insulation is an example of a marking that a client thought was mold contamination. The black material was a pigment, not mold, and was associated with the product's manufacturing process. However other samples of this fiberglass batt were found to be contaminated with Aspergillus sp. - it was not visible to the naked eye.
The mattress and bedding photographs shown below are discussed at Mold on Clothing, Cloth, Bedding
Below are photographs from two different buildings each of which suffered significant mold contamination in the metal wall stud cavity. Both buildings conducted water around the walls from a single leak point source when water flowed in the metal sill plate.
It's less surprising to find mold growth on a stainless steel surface if you consider that the surface may have had a film coating of food or other organic material. The moldy stainless steel sink in these photographs was in a home that had been left flooded for two or more weeks.
Mold may be found in surprising locations in modular homes depending on the home's delivery conditions and construction history. Residential modular home structures include cavities between floors and some walls that an inexperienced inspector may fail to consider. Knowing that water had entered this modular structure we obtained permission for some destructive inspecting that helped track how water had moved through the building.
The brown mold on OSB subflooring (below left) is most likely a very different genera/species than the green OSB mold at below right.
At below left is brown mold on OSB sheathing used in a roof structure. At below right our moldy OSB subfloor photo illustrates one of our favorite molds, Stemonitis sp. - often found growing in a fairy ring pattern on OSB subfloor that has been soaked. Se observed this mold growth in partly-repaired condominium that had suffered burst pipe flooding in upstate New York. Also see Mold on Subflooring
These photographs illustrate mold growth on painted wood framing and subfloor over a wet basement. The colors suggest that more than one mold genera/species is present.
Our photograph of mold on wall paneling (below left) illustrate how mold growth may appear on these materials. At below left the dominance of mold at a building corner combined with the water stains on the block wall at the right side of the photo argue for a water problem that may be traced to a downspout spilling at the building corner outside.
The second mold photo (below right) shows black mold on light colored wall paneling. Actually a closer look showed at least three different colors of mold [click to enlarge any of our images] and thus probably multiple species of mold present on this surface.
The pictures just below illustrate more subtle mold growth on wall paneling as well as how careful use of light can show up much more mold on a surface than may at first be apparent.
Mold growth variation on different components of wood paneling
As our photos below illustrate, moldy wood paneling in buildings can be tricky to spot because the mold may be hidden on the wall-side of the paneling and be not present or at least not visible on the room side (photo at below left). This problem is discussed at Hidden Mold Behind Paneling. .
We also find different mold growth in quantity and sometimes genera/species in the grooves on wood paneling than on the surface of wood paneling (photo, below right). The explanation may be that the groove cut in laminated wood paneling exposes a different texture and wood species as well as exposing a different coating (black paint or stain).
The different texture of a milled groove in some wood panels grabs more moisture or more airborne spores than the harder smoother finished segments. This is another example of the trip-ups in indoor mold tests. Even eschewing an air "test", a surface sample will be entirely different depending on whether or not you stick the collecting tape on those black-painted wood grooves.
Several mold species grow readily and quickly on papers exposed to water or even high humidity, as we illustrate with our photos of file cabinet flooding below left and right.
When papers and paper file folders remain in a wet area heavy mold growth, including Aspergillus sp. are likely to be found. At below right we appreciated the irony of finding this moldy magazine in a flooded home - Fungi Perfecti.
Our photographs below illustrate how mold growth appears on solid pine wood paneling. At below left the rough-sawn pine boards were installed over drywall in a home where basement flooding had gone unattended.
At below right the bevel-edged traditional pine paneling installed on stairwell walls and in the home's basement was severely mold damaged.
Watch out: we sometimes find extensive mold growth on the wall-cavity side of pine paneling in damp or wet homes even if the room side looks clean. The un-coated surfaces of wood products take up moisture and thus can support mold growth more quickly than a coated and moisture-resistant surface.
Our field investigation work and lab testing suggest that plaster is somewhat resistant to mold growth but by no means
These two pictures show mold growth on plastic controls: the knob for a kitchen stove and on handle for an oven door handle. This home had been subject to flooding that was undiscovered for at least several weeks.
Other examples of mold growth on plastic surfaces commonly found in buildings are illustrated below: a plastic light switch cover hosting mold growth, and plastic keys and other items stored in a drawer in a wet building.
The plastic nasal spray bottle sampled by a reader appeared clean when used and visibly moldy 8-10 hours later. We identified Cladosporium Sp. as the dominant fungus growing in the sample provided.
The pictures below show common examples of mold found on the attic-side of roof sheathing. For details also see Mold on/in Attics and attic surfaces.
The photographs below illustrate mold growth on tongue and groove roof sheathing in an attic.
Photos below are examples of mold growth on shelving and a bookshelf surface. The furniture at right is a wood veneer material.
Mold on plywood subflooring can be difficult to spot if the mold contamination is not extensive, but the green mold visible in our right hand photo of the same subfloor is a warning of wet or damp mold-conducive conditions in this area. And watch out: finding this mold sign is a reminder that the rest of the structure needs careful inspection as there may be a larger problem elsewhere.
At below left our photograph illustrates mold growth in a pattern and locations common on the subfloor over a damp or wet basement or crawl space. At below right the fungal growth on this wet subfloor confirms an extended period of very wet conditions.
Also see Mold on OSB Sheathing Board.
The photo at below left was sent by a client who was investigating suspected-mold growth at the edge of a swimming pool liner and coping. We suspected and lab tests confirmed that this was an insect material not a fungus.
Our second photograph (below right) illustrates a common mold that was found by our lab test of deposits on a swimming pool surround.
Our photographs below show mold on ceramic tile grout joints. We also find mold growth on actual ceramic tile surfaces - we believe that in that case mold is hosted on a film of organic material such as soap. See BATHROOM MOLD for more detail about mold on bathroom surfaces including tile and tile grout.
Our first moldy wood trim photos (below) show severe mold contamination on indoor wood trim at a door (below left) and in a wet basement (below right).
At below left we illustrate black mold growth on drywall that was exposed when we removed wood trim to check wall conditions following a wet floor that was soaked due to a burst toilet tank. Finding this mold less than 24-hours after the leak event indicated that this mold was almost certainly pre-existing condition. We traced a leak to a trim opening on the exterior of this wall.
At below right we illustrate a common condition found on the back of wood floor molding: a combination of house dust and debris, water stains, and mold along the bottom edge (upper left in our photo).
Below you can see photographs of moldy wallpaper in a bathroom shower.
At below left we show Stachybotrys chartarum black mold that was found on the hidden side of wallpaper below this leaky window in a Maple Shade New Jersey condominium. Lab identification was, of course, required. We discuss the window leak that caused this mold, its extent, and what was done about it, in more detail at DRYWALL MOLD.
At below right is a melange of mold growths on the wall and ceiling of a pre-1900 home.
A leak from above led to mold growth on the top of this window jamb. Hidden mold in the ceiling and wall are likely (below left). Our second photo shows a common mold event: growth on window muntins, probably due to condensation on the window glass. But this window mold was more extensive than usual.
At below left we illustrate a very moldy window sill in a home that had been exposed to unattended flooding. At below right we show the first of three moldy window sash photographs that indicate chronic or prolonged exposure to wet, moldy conditions.
Below left and right we show close ups of mold found on the window shown at above right.
The black mold found on wood framing (floor joist at below left and wall studs at below right) is an indicator of chronic wet conditions and neither of these cases are likely to be Black cosmetic mold that we find on some new framing lumber.
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