Black, white, and even pink growths commonly referred to as mildew are actually forms of mold. So, all mildew-killing strategies are mold killers as well.

Molds are in the kingdom fungi, algae is in the kingdom protista with things like protozoa and slime mold.

About Mildew/Mold:
Mildew is the type of fungi that form a superficial, usually whitish growth on plants, outdoor furniture and various organic materials. Mildew mold secretes an enzyme that decomposes organic matter and uses it for growth and reproduction.

Many people refer to 'mildew' as the commonly occurring fungi that grow on damp clothing or bath tiles. In reality, such growth is typically a filamentous mold (genus: Aspergillus) of the types likely found on water-damaged building materials.
To test for mildew, simply dab a few drops of household bleach on the blackened area. If it lightens after one to two minutes, you have mildew. If the area remains dark, you probably have dirt. See taxonomy below.

Mold can grow on almost any substance as long as it has a carbon-based food source, moisture, oxygen, and the temperature is between 40 and 100° F.

Most molds reproduce by forming spores that disperse into the air in search of more food and moisture (a reproductive activity similar to seed dispersal from plants). Due to the diversity of mold in our environment, outdoor air normally always contains some level of these airborne mold spores.

Mold growing on glass, ceramic tile, metals, or other inorganic materials is not obtaining nutrients from these substrates. In these cases, mold is feeding on microscopic organic matter that is on the surface or trapped in tiny pores of the material. Bath-tile mold is an example: Mold is typically consuming organic dust, dirt, debris, skin flakes, body oils, soap scum, etc., and the ceramic tile is simply a foundation for the colony.

Mold has been implicated as a major cause of Building Related Illness (BRI) and Sick Building Syndrome (SBS). Studies have shown that exposure to indoor mold can induce respiratory illness in adults, and can cause early onset asthma and allergies in children.

Inactive spores are all around you, too small and insignificant to be seen with the naked eye. You cannot rid your home of inactive spores, nor can you prevent them from entering.

When you dry and disinfect active mold spores, they do not actually die. They return to their inactive state, harmless but capable of activating again. For this reason, you should always vacuum immediately after cleaning up a mold problem, in order to remove the spores that caused the problem in the first place.

About mildew/Mold | How to get rid of of Musty Smells | Types | biocides/antimicrobials/fungicides (Chlorine bleach, Oxygen cleaners) an expert at treating mold and alge.

I did an experiment in th 70's to get black mold off our cabin siding. I tried, bleach, commercial cleaners (e.g. DeckRenew), wood bleach (Oxalic acid) and OxiClean. Oxygen Cleaner worked best. I used it at 4-5 times the regular strength. A heavy bristel brush worked best on thick mold accumulations. Power washing to get the oxygen cleaner off worked in most cases.

Mold likes linseed oil based paint. When I painted with latex my mold problem was reduced significantly.

When you ignore mold for years at a time, it can penetrate fibers of the wood and be almost impossible to remove.

Bottom line:
Oxygen bleaches (e.g. OxiClean, Wolman DeckBrite, ) are more gentle oxidizers than chlorine-containing bleaches such as household bleach. Chlorine bleaches tend to cause excessive pulping of the wood to give a fuzzy surface. Some commercial cleaners contain strong alkali (sodium hydroxide or potassium hydroxide). Other comercial cleaners contain oxalic acid which will neutralize iron stains and tannin stains, but is not very effective for mold or algae. Oxalic acid will also brighten the wood.

Deck Paints and Resurfacers
How to remove black mold | TodaysHomeowner
Begin washing the deck surface area with a cleaning solution—a deck cleaner, liquid dishwashing detergent, and water solution or bleach solution and scrub using a soft-bristled brush.
Using a vinegar solution in a spray bottle, spritzing the mold, and then letting the vinegar soak for an hour will also help kill the mold and its spores to prevent further spread. After that, wipe the deck area using a rag or clean, damp towel.
If the mold or discoloration is still present, use fine-grit sandpaper to clear the surface that the mold is growing on.

How to Prevent Mold on Decks | DeckStainPro

From: info
For mold and mildew, I have always used diluted bleach with some dish soap in it. I would use a soft bristle brush as opposed to a wire brush (wire is too harsh for wood decks).

Here are some other ideas: Preserva Products Customer Service -
Preserva Products | Preserva Wood See Chlorine bleach and Oxygen cleaners

RAD Guard Mildew Cleaner & Preventer Review | DeckStainHelp

How to Clean a Deck the Right Way says,
How we cleaned a deck,
We used sodium percarbonate from Pressuretek at around 5 ounces per gallon. We pressure washed the deck with the M5 Twist nozzle, providing just enough pressure to remove grime and dead wood fibers. We followed up with oxalic acid, also from Pressuretek, at around 6 ounces per gallon. With the proper chemical application, pressure washing, and thorough rinsing, you can expect amazing results from just a bit of hard work.

Source: Household Products to Clean Mold With. Dangers of Mold. |

Most recommend a soft bristle brush, but you can also use:
fine plastic mesh pads, Scotchbrite pads, nylon coated sponges, fine bronze wool.

How to Get Rid of Musty Smells
Common answers Links:Is Deck Mold Dangerous?
Google it
3 Ways to Kill Mold Naturally | Care2 Healthy Living
How to Get Rid of Musty Smell |
Household Products to Clean Mold With. Dangers of Mold. |
How Can I Get Rid Of The Sour House Smell? |
How to fix a leak around your tub or shower spout.
Homemade Remedies to Get Rid of Bathroom Odors - Yahoo! Voices

Mold - (Phylum: Ascomycota)
AlternariaA large spore mold that can deposit in the nose, mouth and upper respiratory tract causing an allergic response. Indoors, it is often found in carpets, textiles, house dust and potentially damp areas like window frames and showers. It can also be found in plant soil.
AspergillusUsually found in warmer climates in areas of water damage or extreme dampness. Aspergillus species are also commonly found in house dust. Many species produce mycotoxins which may be associated with disease in humans and some animals. Also found in building materials and in fall leaves and other decomposing matter like compost piles.
CladosporiumThe most commonly identified outdoor fungus, but it can easily enter into the house through the HVAC and other airflow entryways. Cladosporium also has an indoor species that grows on textiles, wood and other porous, damp areas. Both indoor and outdoor species are triggers for hay fever and asthma symptoms.
PenicilliumA very common mold known to cause allergies, hay fever and asthma. Species may be found growing on wallpaper, wallpaper glue and decaying fabrics in water-damaged buildings or homes. It is also found in carpet and in interior fiberglass duct insulation. Some species can produce mycotoxins.
StachybotrysPronounced (stack-ee-BOT-ris), this is an especially toxic black mold that produces airborne toxins (mycotoxins) that can cause serious breathing difficulties, memory and hearing loss, dizziness, flu-like symptoms and bleeding in the lungs. Stachybotrys requires excessive moisture to thrive (usually running water) and is a slimy black mold. Fortunately, stachybotrys is not found in homes as often as the other molds listed above.
Green Algae (Phylum: Chlorophyta)
Blue-Green Algae (Phylum: Cyanobacteria)
Source: Indoor Air Quality and Your Health at National Allergy

Table 2. Common types of moldy and decay fungi in buildings



Fungi group or species


Brown-rot fungi

Coniophora puteana (Cellar fungus), Fibriopoia vaillantii (Poria), Meruliporia incrassata, Fomitopsis palustris, Fomitopsis palustris, Antrodia carbonica, Gloeophyllum trabeum, Neolentinus lepideus, Postia placenta, Tapinella panuoides


White-rot fungi

Donkioporia expansa (Stringy Oak rot), Flammulina velutipes, Phanerocheate chrysosporium, Shizophyllum commune, and Trametes versicolor


Soft-rot fungi

Chaetomium globosum, Paccilomyces variolli, Phialocephala dimorphospora, Phialophola mutabilis, Scytalidium liqnicola;


Water conducting, i.e. dry-rot

Serpula lacrymans, Meruliporia (Poria) incrassata


Airborne pathogenic fungi

Aspergillus, Absidia, Rhizopus, Mucor, Cryptococcus neoformans, Histoplasma capsulatum, Blastomyces dermatitidis, Coccidioides immitis, Penicillium sp., Alternaria, Cladosporium, Helminthosporium, Stachybotris.


Fungi with most frequent spores in the outdoor air

Cladosporium, Aspergillus, Penicillium and Alternaria


Frequent indoor fungi

Aspergillus niger, Aspergillus favas, Chaetomium globosum, Oidium lactis, Phytophtora infestans, Fusarium caerluleum, Penicilium glaucum, Penicilium notatum, Penicilium brevicompactum, Penicilium expansus, Sphaerrolitis, Lauconostoc, Phoma Exigue Foevata.,


Fungi on masonry

Cladosporium, Phoma, Alternaria and Aureobasidium, (grow on the deposits of dead algae and other organic matter)


Fungi on paints

Pullularia pullulans (blue stain on paint coat, break down of the oil resins)


Indoor mold

Common molds are gray mold (Botrytis), pin molds (Rhizopus sp.), gray and blue molds (Penicillium, Aspergillus).


Kingdom: Fungi
Phylum: Ascomycota
Order: Eurotiales
Family: Trichocomaceae
Genus: Aspergillus
blue mold, 
Powdery Mildew
Kingdom: Fungi
Division: Ascomycota
Class: Leotiomycetes
Order: Erysiphales
Family: Erysiphaceae
Genus: Blumeria
Powdery Mildew
Downy Mildew
Kingdom: Chromista (Straminipila)
Phylum: Heterokontophyta
Class: Oomycete;
Order: Peronosporales; 
Family: Peronosporaceae; 
Genus: Peronospora;
    mildew (tobaco, onion)
    downy mildew

Stuff to organize:
mold (a type of fungi)


Molds come in many colors; both white and black molds are shown here.

Biocides are substances that can destroy living organisms. The use of a chemical or biocide that kills organisms such as mold (chlorine bleach, for example) is not recommended as a routine practice during mold cleanup. There may be instances, however, when professional judgment may indicate its use (for example, when immune-compromised individuals are present). In most cases, it is not possible or desirable to sterilize an area; a background level of mold spores will remain - these spores will not grow if the moisture problem has been resolved.

Toxic mold grows in a no sunlight environment with a constant water source like from a leaking pipe. Sodium hypochlorite (NaClO): This chemical -- chlorine bleach -- is good for removing mildew but isn't effective on dirt or other stains. So mix it with an ammonia-free detergent. Thoroughly rinse the deck after using this chemical because it can eat away at the wood, resulting in fuzzing and premature graying.

Oxygen cleaners - Oxygen bleach: These use one of three possible active ingredients: hydrogen peroxide, sodium percarbonate, or sodium perborate. When mixed with water, this chemical forms hydrogen peroxide (an oxygen-based bleach) and sodium carbonate, which acts as a detergent. It is good for removing dirt, mildew and weathered wood.

Oxalic acid: This is effective in removing iron stains and the brown-black tannins that frequently occur with cedar and redwood decks. This acid is commonly found in deck brighteners. Oxalic acid isn't effective against mildew, so you may want to use it after cleaning the deck with a bleach-based cleaner.
Source: Go From an Old Deck to New in 4 Steps | This Old House

See also: Mold_growth, assessment, and remediation - Wikipedia

Bleach: Concentrations range all over the place:
Painted surfaces interior: 1 cup/gallon

For untreated wood: 1/4 cup/gallon (1:64) to 1 quart to 3 quarts (1:3)

Rid Your Home of Mildew at North Carolina Cooperative Extension Service says,
Prepare a solution of 3 quarts warm water, 1 quart chlorine bleach, 1 ounce detergent and 3 ounces trisodium phosphate (TSP).

Kingsley-Bate: Elegant Outdoor Furniture says,
Scrub the wet furniture using a soft bristle brush and a solution of 2/3 cup laundry detergent and 1/4 cup bleach in 1 gallon of warm water. When finished, rinse the entire piece with more fresh water to remove any remaining cleaning solution. This procedure is sufficient for general cleaning.

What is the correct mixture of bleach and water for killing mold and mildew from water damage? at Yahoo Answers says,
You need more than just bleach and water to kill mold and mold spores. You can wipe what is visible with a wet rag and most of what you have will disappear, however, the spores are still there. There is only one product sold that will take care of your problem now, and keep the problem from coming back. That is called trisodiumphosphate, or more commonly TSP. Look for it in Lowes, Home Depot, etc type stores. You want the Blue and White colored box with red lettering. Then mix 1 gallon of water, any temperature, with 1/2 cup bleach, 1/4 cup of something like Tide powdered detergent and 1/2 cup of TSP. says,
The bleach and water solution can work for many types of mold. What people don't know is it will not work on all types of mold. For years people have been cleaning up mold with bleach and water. Why not? It is cheap and works well in most cases. Bleach does not kill all types of mold. The levels of mold and different types require a anti-microbial solution to get rid of the mold growth. This is the best route to get rid of isolated areas and patches of mold. The anti-microbial solution is also used on large mold problems where a house has flooded and required a dry-out and cleaning to make the house safe again.

Kill mold using chlorine bleach use 1/2 to 1 cup of bleach to a gallon of water. The mixture can be applied from a spray bottle or from a bucket using a sponge or cleaning cloth. Chlorine bleach does not kill mold on contact. To thoroughly kill the mold using bleach it is important to leave it on the area at least thirty minutes.

Alternatives for porous surfaces are:

Eliminate, Clean & Prevent Mold with Concrobium Mold Removal Products
Source: Mold Removal, How to Kill Mold with Bleach, Borax, Vinegar

Oxygen Bleach:
Sodium Percarbonate (Ingredient in OxiClean)
Actually my OxiClean box says in contains sodium carbonate, sodium carbonate peroxide, C12-15 alchols ethoxylated, sodium chloride.
It is an excellent detergent and bleaching agent based on hydrogen peroxide. It is a good cleaning and bleaching agent at normal temperature, and has strong fungicide effect. (Fruits and vegetables treated with sodium percarbonate can be kept fresh, and be stored for a long time. In medicine, it can kill staphy lococcus, and colon bacillus.)

This product is a white particle powder, non-toxic no contamination, non-flammable, non-explosive, easy to get damp, and soluble in water. It is efficient, safe and economical. It is environmentally safe, biodegradable, leaves no harmful by-products or residues which can harm the environment. Except for industrial-strength cleaning or stripping jobs, sodium percarbonate is, hands-down, the choice for most average wood preparation jobs.

Directions for Oxygen Bleach:
add 6 to 8 ounces of oxygen bleach per gallon of hot water. The hot water activates the sodium percarbonate in the oxygen bleach. Mix with a stirrer or painter's stick.

Use a sponge or mop to apply the bleach mixture. Allow it to sit for about 30 minutes. Afterward, use a stiff-bristle brush and scrub the area. Fill a second bucket with hot water and rinse the treated area with a sponge or mop. When complete, inspect for any remaining mildew. Reapply the bleach mixture as necessary.
Source: Mold and Mildew Remediation Techniques -

Recently, some companies have begun using dry ice blasting to remove mold from suitable surfaces, such as wood and cement. Soda Blasting is also a good method to remove the mold. Media Blasting, which removes mold is a preferred method to encapsulation, which only cover the mold.
In most cases, common household cleaning products and disinfectants are used for this task. FEMA also suggests the use of disinfectants and sanitizers on the ductwork for the heating and air conditioning system, if it has been flooded.

Indoor Air Quality (IAQ) at

How to Clean after Flood and Mold (and what NOT to use) | Be Toxin Free
Many of the products sold as biocides/antimicrobials/fungicides are more dangerous than the mold and its byproducts. Do you really want to trade one toxin for another?

The funny thing about biocides is that many of them are water-based, and the active ingredient evaporates relatively quickly. Bleach for example, is 3% sodium hypochlorite and 97% water. When you use bleach during mold remediation, the sodium hypochlorite dissipates rapidly, leaving behind what? Water! Congratulations, you've just added water to a water problem. Spores will settle on the dampness you leave behind, eat the dead mold you didn't remove, and grow right back again. Nice, eh?

Why Are Biocides Not Recommended for Mould Remediation? from MOLD & BACTERIA CONSULTING LABORATORIES Lime sulphur is an example of eradicant biocide that acts by killing moulds on contact. Biocides that kill mould are said to be fungicidal.

Mold Cleaner: BioCide100 Kills Mold, professional Mold Cleaner,EPA Registered

Shockwave Disinfectant, Sanitizer, Fungicide For Mold Remediation

Concrobium 1-gal. Mold Control Jug-025001 at The Home Depot

Mold Removal Products: Mold Cleaner, Mold Killer, Mold Prevention
  MoldSTAT Plus. EPA Registered - Kills mold and mildew.

Odor Eliminator - Car & Home Odor Control - Any Odor Removal Guaranteed -

Concrobium 1 Gal. Mold Control Fogger-200-620810 at The Home Depot $329

Conflicting Information:
Many mold remediation sites on the web include the following. I couldn't find the original source and question the conclusion.
"The chlorine in bleach cannot penetrate into porous surfaces such as drywall or wood. The chlorine is left on the surface of porous materials and only the water component of the bleach is absorbed into the material, providing more moisture for the mold to feed on.

Some of the mold on the surface might be killed but the roots of the mold are left intact meaning the mold soon returns, leaving you in a cycle of repeated bleaching. Perhaps this is why some people believe that spraying bleach on mold doesn't affect it but instead just bleaches its color so you can no longer see it."

At The Truth About Mold Removal - Bleach vs. Vinegar - All Star Cleaning Services they say "Molds have roots (hyphae) and bleach’s ion structure stops chlorine from penetrating porous materials/"

The sodium hypochlorite in bleach is in a solution not a suspension. We're talking about nanometers, I don't think the difference between water H2O and Sodium hypochlorite (NaClO) is significant enough to affect penetration.

Concrobium Mold Control. contains Sodium Carbonate and two other ingredients in the solution which, when combined with the sodium carbonate and the water, result in this patented tri-salt polymer that eliminates and prevents mold.

Deck Cleaning Q&A. A look at Deck Cleaners and what's in them. says,
I see cleaners on the market that use Oxygen Bleach (OxiClean Sodium percarbonate, sodium carbonate peroxyhydrate, and sodium carbonate peroxide) and then an Oxalic Acid which makes sense since the Oxalic Acid does a good job of killing fungi and the OB bleaches the wood."
The EPA says "Oxalic acid is not very effective for removing algae or mold."

How to Clean after Flood and Mold (and what NOT to use) | Be Toxin Free, says EPA tests say Borax works better than bleach. I couldn't find any such study.

Disinfecting in health
Preperation & Priming wood for stain or paint.
Indoor Air Quality and your health.
Musty Smell in Clothes
How to clean a washing machine.
Cleaning Tips for Exterior Siding | Ask the Builder
How To Clean Mold Off Cedar Siding |
Maintenance of Cedar Siding: Removal of Algae, Mold, and Iron StainsLab Notes | Forest Products Laboratory/US Forest Service (
Which Oxygen Based Cleaner Works the Best?: Does It Work? - KCBD NewsChannel 11 Lubbock

last updated 12 Nov 2015