Cheryl’s Top 15 Steps to Avoid Mold

Mold from vent

Architect and mold survivor Cheryl Ciecko shares her top 15 considerations for avoiding mold in homes, avoiding mold illness or recovering from other chronic health challenges.

Check humidity levels

Check in all rooms with windows closed for a day. Use a $10 humidity meter from Wal-Mart or Move it from room to room each day and monitor levels, looking for inconsistencies. Above 55% moisture in the air in the summer, with windows closed, is a red flag. Above 40% humidity during the heating season is also an indicator to check further. The humidity should NOT be higher in your house with the windows closed than outside. 

Check for any history of leaks or floods

If no areas have high humidity there is a good chance you are safe from active mold growth. But past mold growth could still be an issue as dead spores are also harmful. This will be even harder to find. Water stains on many materials may be evident. Wood and drywall are particularly prone to staining after being wet and is a tell-tale sign of potential previous water problems. Brick often tells a story after rain events. 

Brick reveals moisture

Look for any type of surface changes

Use a flashlight. Double check by examining all moisture prone areas, either yourself or by hiring a professional (to inspect a furnace or pull out a dishwasher, for instance). Signs of water damage include bubbling of drywall surfaces, surface color changes, white crystals on drywall surfaces, a white powder on drywall surfaces, check for any discoloration at low areas next to the structure outside, look for streaking signs in outside finishes, consider spalling of masonry faces or moss growth.

Surface color changes on drywall

Check gutters

Make sure gutters are clear and that downspouts are directed far away from the structure, effectively taking water away. This may require you to walk around the building in the rain looking for any place where water is not flowing away. The ground around the perimeter of the home should slope away from the home, downhill, noticeably. The recommended amount is 6 inches down in 10 feet away from the structure. Ground should be at least 6-8 inches BELOW the top of the foundation wall. 

Gutters should drain away from structures

Look around in your attic

Look at the underside of the roof sheathing for any discoloration or water staining. In the winter, look in there to see if there is water dripping off exposed nails due to condensation. Obviously, look for any color changes, fungus growth, mushrooms or streaking. Some black spots might be harmless staining so just take note and photograph, if possible. In older buildings, evidence of past leaks or water might not be a problem if the wood is dry and simply water stained.

Check the attic

Check all exhaust fan outlets

Make sure that they go directly outside and are clear. This includes kitchen and bath exhausts as well as dryer vents. EXHAUST FANS should NEVER be vented into attics, basements and crawlspaces or inside the building

Check the outlets of your exhaust fans

Use a surface moisture meter

Buy a $50 surface moisture meter to check other prone areas. I prefer digital meters.

➡️ Check out my Favorite Tools HERE

Look for a digital-read one that measures up to 99%, with good recommendations on or elsewhere. I bought one at Costco years ago, that has worked great for me but that model is no longer available. A similar model is listed through the ‘Products’ link on this website. Surface moisture meters are easy to use. Select a setting to match the material you are testing, such as drywall, hardwood, softwood or masonry. (Use the masonry setting for tile.)

Hardwood is for flooring, softwood is for subfloors and other structural wood. Find a typical reading for the surface and then run it slowly in prone areas looking for changes. Drywall should be very close to 0%. Wood should be under 10% depending on your location. For other materials look for variations from a norm that you will need to determine. Prone areas include rooms that test for high humidity: around windows, doors, walls and floors of showers, floors near toilets, tubs, sinks, dishwashers and washing machines.

Keep looking

If you find nothing, and continue to have symptoms consistent with mold illness, keep looking. Sometimes the moisture is only evident in certain seasons or conditions, such as prolonged rain events or due to ice dams in winter. Check again after rain events. Walk outside while it is raining and look for discoloration or evidence of water collecting on the ground, the walls or roof. Check gutters to notice if they are draining properly or overflowing randomly.

Purify the air

Run a quality air purifier in living and sleeping spaces (sleeping space is #1). You can also make your own very inexpensive DIY air purifier! (instructions HERE). 

Remove all clutter

Keep sleeping rooms clear of clutter and remove all books and carpet. Encase mattress and pillows, remove stuffed toys and excess pillows. Dust free will be mold free. Mold rides on the backs of dust particles. 

Old books

Vacuum Often

Use a HEPA vacuum regularly to keep dust from accumulating. Clean with an essential oil fungicide cleaner, or other none toxic products regularly.

Check HVAC filters and change regularly

Do a swab test of the inside of ducts to test for mold. Check condensate drains to be sure they are functioning properly. HVAC systems are common sources of mold and should be checked regularly anyway by an HVAC specialist. Duct cleaning should be done about every 8 years. Scams abound in this industry, so make sure to check for agency certifications.

Check locations where you spend a lot of time

Check other places you frequent on a regular basis, such as your car (change the cabin air filter!), office, or school.

Try Using Essential Oils

Diffuse, with full strength, essential oil as a fungicide for 24-48 hours with the room closed off. A special diffuser/nebulizer is used for this. Contact Cheryl for more on this topic.

Coffee beans

Review your diet

Eat clean and avoid these common moldy foods such as coffee, peanuts and peanut butter, roasted nuts, processed apple juice, corn and all grains. 

Cheryl Ciecko is an ALA, LEED AP, Licensed Architect who helps homeowners and building professionals create safe homes through online education to prevent mold, water damage, and poor indoor air quality. 


You can find her video masterclasses, online programs, and education subscription options at .


For detailed answers on your specific situation or building project, schedule your appointment for an individual consultation.




The information contained in this presentation is for educational purposes only and is not intended to diagnose, prescribe, treat, or cure any disease, ailment or injury to the body. It is not medical advice. FDA regulations prohibit the use of medical claims in conjunction with the sale of any product not approved by the FDA. Statements made herein have not been evaluated by the FDA. 

Any products, techniques, and/or personal usage tips referred to are not suggested as a replacement for proper treatment from a licensed health care professional. I am not a licensed health care professional and the decision to use or not to use any of this information is the sole responsibility of the listener and/or reader. Everyone is an individual with different body types, different blood types, different body chemistries, and it is important to remember that what works for one person may not work for another person.