mold free home

Mold growth is always caused by too much water or humidity inside the living spaces

Reasons for high humidity

  1. water leaks
  2. no or low performing exhaust fans
  3. single pane or broken windows
  4. no insulation in perimeter walls
  5. too many people or contents in a small space

Water leaks

Please contact your landlord, facilities manager or property management team as soon as possible, even if it is after business hours if your apartment experiences a leak. The sooner the leak can be stopped, water removed, and professional drying started; the less chance mold will grow from the leak. Everyone wins this way.

Tenants may also want to consider renters insurance. There are times when tenants may have to pay out of pocket.

If you are a property owner, please start professional drying as soon as possible.

No or low performing exhaust fans

The reality in San Francisco is exhaust fans aren’t always possible in many of our beautiful historic buildings. If you don’t have a bathroom exhaust, please do leave a window open after bathing, if it is safe to do so.  If your exhaust fan seems weak, take a piece of toilet paper and see if the fan will hold the toilet paper next to the vent when it’s turned on. If it doesn’t pass the test, you may choose to discuss this with your landlord. Exhaust fans can prevent water damage to the building.

If you are a property owner, a small investment in a new exhaust fan will save you countless dollars for building damage and mold remediation.


Single pane windows can create interior condensation. It is usually time and cost prohibitive to replace historic windows in San Francisco.

By working together landlords and tenants can reduce mold growth by leaving breathing space between furniture and windows/walls.

Store clothing and shoes in sealed, plastic containers when possible. For instance, if you store your party shoes under your bed without putting them in a plastic box, you may have mold growth on your shoes. Do not store items in cardboard boxes – mold loves cardboard. Mold “eats” cellulose, so paper is it’s favorite meal.

No insulation

Again, this is one of those things that tenants and landlords need to work together to reduce interior damage. A simple humidity gauge will tell tenants when it’s time to turn on exhaust fans or open windows. Any time the humidity is greater than 52% it’s time to get some fresh air inside.

If you are a property owner, adding insulation should be considered when you open interior or exterior walls. Also insulation below the floorboards in a crawlspace can save you money on heating bills and keep the interior humidity in a normal level. Please check with your accountant as there may be tax benefits available for these upgrades.

Too many people or contents

San Francisco has very high rents. This means more people living in smaller spaces.

Open the windows

Turn the exhaust fans on if there a lot of people using the kitchen and bathroom. You may need to leave the exhaust fans turned on all the time.

Tenants may need to rent storage for excessive contents. Definitely store all clothing, paper, and shoes in sealed plastic containers.

If you are a homeowner, keep your contents in sealed plastic bags and bins. You won’t have unpleasant surprises the next time you dig your suitcase out of the basement.

Call us to discuss your project at 415-337-2923.

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