Store No More

Homeowner Newsletter, Summer 2025
©2025 Jeffrey C. May

Storage habits can have a negative effect on indoor air quality.

An exterior closet: A closet with at least one exterior wall can be cooler than a closet that has all walls that face warm interior spaces. Then mold growth can occur on the exterior wall and even on goods near the floor or in contact with or near that wall.

Some storage tips for an exterior closet:

• Don’t store a lot of goods in an exterior closet.
• Goods in an exterior closet should be up off the floor and away from the exterior wall(s).
• In the heating season (from late fall to early spring), in very cold weather keep the closet door ajar or install a louvered door to help warm the closet. There are also heaters specially designed for closets.

The garage: Most garages aren’t heated and cooled and thus can develop elevated RH conditions that can lead to mold growth. In addition, moisture levels become elevated when cars covered with rainwater or with snow are driven into the space.

Some storage tips for a garage:

• To reduce the surfaces on which dust can collect and behind which mice can hide or nest, keep as many goods as you can in tightly lidded plastic bins.
• Rolling metal shelves are convenient, because they can be easily moved around if you want to clean garage surfaces.
• If your garage is attached to your house, don’t keep paint cans, mowing equipment, or cans of gasoline in the space; otherwise, VOC (volatile organic compounds) in the garage could become elevated.

An unfinished basement: I have worked with many clients whose houses are immaculate but whose unfinished basements are full of stored goods and mold growth.

Some storage tips for an unfinished basement:

• Don’t place anything biodegradable (cardboard, wood, paper) on the concrete.
• Keep goods on shelving; rolling metal shelves are best and should be placed at least a foot away from concrete.
• Keep as many goods as possible in tightly lidded plastic bins, BUT…
• Don’t store anything while it’s still wet.

Moving: You may be moving into a new home but have to store some personal goods meanwhile until your new home is ready for occupancy.

Some storage tips when moving:

• Don’t park goods in a musty space, such as a garage or storage shed.
• If you want to store your goods in a professional storage facility, be sure that the air in the facility is conditioned (heated/cooled) as appropriate for the season.

Photographs in this article are available with permission: jeff@mayindoorair.com.