Mold Free Construction

This page contains educational material about water damaged buildings and building methods/materials that will decrease the chance of your buildings becoming moldy. I am doing my best to get this data up quickly and correctly. If you find errors in this data, please let me know.

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Trying to find a house that is mold free is difficult. Not only are some materials moldy prior to installation, contractors may use building techniques that are more prone to mold growth. I all too often see contractors building in the rain without protecting the house or apartments they are building. These buildings can be sitting in the rain for days on end with the cellulose materials just soaking up the water. There is no practical way to eliminate all mold and mold spores in the indoor environment. We eliminate them as much as possible through proper building materials and methods and in addition, we control indoor mold growth by controlling moisture.

If you feel you are living or working or being educated in a moldy building, you can get information on testing here.

I suggest you read the World Health Organizations Indoor Air Quality Report of 2009. You can download it here.

I would also suggest you read the "Indoor Environmental Professionals Panel of Surviving Mold Consensus Statement" on "Medically sound investigation and remediation of water-damaged Buildings in cases of CIRS-WDB."

Trying to build a home with materials and construction techniques that will be less likely to grow mold is also not an easy task. This page lists links to websites with details on building methods to decrease mold growth in homes as well as building materials that are less likely to grow mold. Let me know your experiences with these products and companies. By using good construction techniques and using mold resistant materials you will decrease your chance of a moldy home. However, you will still need to be diligent about not bringing moisture or moldy items into your home.

Keep in mind that we want mold resistant materials that are non-wicking. Wood is often used in building but you have to assume it is contaminated from the get-go. Often it already has mold on it, even if you do not see signs of it. Some builders suggest to use a mold-resistant mineral coating on wood used in buildings. A friend of mine suggests Lime paint (whitewash) and borax as two options. Also stay away from or limit the following mold-growing materials - paper backings, resin-containing boards (like particle board, melamine, etc.), fiberglass, foams - including "eco-foam".

The data below is listed in alphabetical order. If you are looking for data, check alphabetically for the category you are interested in.

Basements: Any part of a building that is below the ground level will be more likely to have moisture issues. It is thought that heating basements to 60 degrees will keep condensation from forming and be less likely to feed a mold problem. However, my suggestion would be to stay away from below grade spaces like basements. If I did have a basement in my house I would put a dehumidifier in it to see if I had much moisture in the basement. If I did, I would try to address the cause of the moisture or at least keep the dehumidifier going.

I would definitely not put a carpet in the basement of anything else that readily grows mold.

Cleaning Up Mold Data: Some good data at this site, but they sell it. They are called WonderMakers.

Building Research, Testing Data: These are some educational materials you might want to check out

•Healthy Buildings Europe 2015 Conference Keynote speaker Miia Pitkaranta on Molecular Studies. A video presentation on bacteria and fungi in healthy buildings.

Cleaning Agents: The two most common used agents are Hydrogen Peroxide and quaternary ammonium compounds. Quaternary ammonium compounds are cationic detergents, as well as disinfectants, and as such can be used to remove organic material. They are very effective in combination with phenols. Quaternary ammonium compounds are deactivated by anionic detergents (including common soaps).

Quaternary ammonium compounds: BenzaRid, MoldSTAT Barrier, Mold Armor has a few: One named MS-501. Make sure you see if these are concentrated or ready to use when you buy them.

Concrete floors/slabs: Concrete that we use tends to wick moisture into it. I have been told that the old style concrete of magnesium oxide actually expelled moisture, but I don't have first hand knowledge of this. If you have a concrete floor or foundation slab, it needs to have some type of liner underneath it to keep moisture from wicking up via the ground into the concrete. Some contractors advocate insulation under it to keep down condensation. It would need to be an insulation that will not draw moisture to itself. You would also want to make sure the barrier stays completely intact or moisture will wick up through any cracks in the barrier.

Crawl Spaces: Most crawl spaces are vented. However, the new thought is that conditioned crawl spaces are a better way to go. I am not so sure about this. Some people have had trouble with these.

Crawl spaces should be designed and constructed to be dry. Crawl spaces should control rainwater, groundwater and provide drainage for potential plumbing leaks or flooding incidents. Some people are conditioning a crawl space by heating and cooling the crawl space as if the crawl space is included as part of the home. Air must be supplied to the crawl space from the home in order to provide this conditioning. Although some contractors suggest returning this air back to the home, I would have it exhausted to the outside unless I was assured by the encapsulation system in the crawlspace that there was no way there would be any type of mold laden air in the crawl space returning to the inside of my home. Ventilating the air to the outside could get expensive. If the air was not being returned to the house, this could be helpful to decrease mold in the crawl space. However, the air is usually returned to the house which could be hazardous.

Crawl spaces must have a ground cover that prevents evaporation of ground moisture into the crawl space. One of the most common is 6 mil sheet polyethylene that has taped/sealed joints and that is attached to the crawl space perimeter walls. This ground cover must be continuous through piers and supports.

Crawl space perimeter walls, steps, rim joist areas and any other concrete or exposed masonry should be insulated with an insulation that prevents moisture in the air from accessing these surfaces and creating condensation.

For more details on conditioned crawl spaces check out this link. Also see the vapor barrier section below.

Drywall: Things to consider would be solid wood, magnesium oxide, perhaps stone or tile. I see drywall being made out of fiberglass but I worry that fiberglass has been known to grow mold as insulation and I am unsure about how this type of drywall is holding up.

Floods: Buildings with heavy damage by flood waters should be assessed for structural integrity and remediated by experienced professionals. Damage with sewage or other contaminated waters brings in a whole new level of problems.


Carpets love to grow mold on the backing. You also get mold in the carpet pile. You can't get it all out and when you clean it, you get it wet and may actually add to the mold issue if you don't get it completely dry within 24-48 hours. If you have someone come into your house or business to clean carpets, and they bring their own equipment to your residence/business, they can also bring mold or bacteria from other cleaning jobs to inoculate your space. Carpets are a great place to grow and harbor mold.

Wood floors are my choice in the house I live in. The only issue with them is if you get wood that is contaminated when it goes in or if you use a high VOC compound to finish it. There are low VOC compounds on the market today. I really like wood floors. To me they are the best of the choices out there. Just remember all wood needs to be finished or any moisture that gets on it will easily grow mold. All natural surfaces such as wood grow mold easily if moisture gets on the area for more than 48 hours. I mop wood floors very infrequently and usually do spot mopping in between. This keeps moisture away from the wood. Technically, the finish will protect it, but I am simply super careful since I am a mold susceptible person.

Insulation: rock wool or aircrete-type-insulation might be your best choice.

Damp spray insulation may be a problem. If you use it, make sure you leave your walls open (no drywall) until the cellulose has properly dried. Finally, you can only damp spray cellulose into open wall cavities where the studs are exposed. Never pump cellulose into closed wall cavities. If you do, you almost certainly will have a moisture problem. (For that application, you would use dense pack (dry cellulose).

Heat Sources

Ductless HVAC


Hygrometer: Relative Humidity Gauge

Tells you how much moisture is in your house. You can find these in an electronic gadget store. This is one I have used and had good luck with.

Radiant Heating in Flooring feels great on the feet and radiant heat of any type always feels nice. However, what will you do if you have a break in the radiant heating system. What if the pipes under your flooring break? Are they built in such a manner that your house will be protected from the liquid and will you have easy access to the pipes to fix them?

Radiant Ceiling Heat

Wood Stove

Moisture: Although moisture is the number one issue to keep in mind for growing mold, there are some molds such as Wallemia that can grow in low moisture environments. So, keep the moisture under control, but realize you can still get a mold issues in lower moisture environments, it is just not as likely. You can use a dehumidifier, as mentioned above to pull moisture out of a house or open the windows as needed. To measure humidity see "Hygrometer" above.

Daily living creates moisture: Make sure you vent any source of moisture such as from showering, washing dishes, clothes, drying clothes, cooing etc. This can be done with exhaust fans and ventilation. Make sure all fans and vents are going to the outside of the building and not into the attic or crawlspace.

Prevent moisture from condensation: Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof, or floors) by adding insulation.

If you have a moisture problem that is not being fixed at least use a de-humidifyer.

Mold is Visible: Oh my, this is really bad. Remediate immediately. Remove the materials with mold on them unless it is non-porous or superficial. Be aware that dead mold can still cause allergic reactions and other health effects in some individuals, so it is not enough to simply kill the mold. It must also be removed. Clean anything in the moldy area with quaternary ammonium compounds in case there are bits of mold or spores you can not see. All surfaces need to be cleaned. In some cases hydrogen peroxide can also be used, but the standard is quat compounds. This needs to be done in a methodical manner so as not to move the spores around the room. Unless is is just a little tiny amount of mold, the area needs to be contained and unless you know how to contain the area and clean it appropriately, it is best to hire a professional. I will eventually have detailed cleaning data available for you as I investigate the best methods and write it up for you.

Check these areas in your home for mold: attic, crawl space moisture, around windows, bathroom tile and grout, basement walls, around and under sinks, all visible plumbing, humidification systems, sprinkler systems.

Vapor Barriers are often a simple piece of plastic laid underneath the house. This works if it covers everything and has no holes. However often this is not the case. There are some encasements that are being used and I saw this one called CleanSpace but then I saw a blog where someone reviewed it and said it stunk of VOCs. You can check it out yourself here.

Clean Space - Crawl Space Vapor Barrier: These folks have a Clean Space Encapsulation system for your crawl space.

This blog says CleanSpace stinks of VOCs.

Wall paper: Oh my, are we trying to feed the mold. The mold loves to grow on that nice glue and the paper. You can create a really great mold environment by wall-papering your house.

Water Leaks: They must be attended to immediately. Any leak no matter how small needs to be identified and fixed as mold grows in 24-48 hours once water is introduced into many building materials.

Interesting video on air filtration during remediation:


Here are some websites where you can get additional data.

A great resource for remediating your building is

Building Science Corporation: Mold in Buildings

Mold in Your Home Video- This is a good introduction to mold issues in the house. Their methods of cleaning, may not be enough for people with extreme mold susceptible haplotypes.

George Swanson - construction consultant

GreenGuard Building Certification for Apartments and Buisnesses: A mold certification.

Magnesiacore to replace gypsum and more.

Mold Free Construction Projects: PATH Project,

Replacement for exterior sheathing, gypsum board,backer board and plywood: JetBoard and other Jet Products

Air Krete They have a mold test on their product that you can view here.

NW Clean Air Agency

SafeStart Variety of testing for buildings

If you found this information helpful, I would appreciate your support in keeping the site going. If you would like to donate to my work, I thank you in advance and send you my deep felt gratitude.

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