Is Mold Really an Issue in Idaho?

I recently went on a road trip from Idaho to southern California and enjoyed some stark change of scenery down the coast of Oregon and California. Growing up in the desert of southern Idaho I often forget how green other areas can be and enjoyed the torrential downpours as I stood beneath the canopy of the California redwoods.

Our neighboring states see more moisture than we do!

As a mold inspection company we are often asked “Is mold actually a problem in Idaho? The climate is so dry!” The question makes a lot of sense, especially for clients who have moved here from humid areas where ideal conditions for mold growth exist almost in perpetuity and efforts to prevent it must be constantly thought about. Although Idaho is a drier climate, we still have sources of moisture that can provide suitable conditions for mold to thrive, whether it be from indoor plumbing, roof leaks, or ventilation issues. While we typically don’t see natural humidity levels high enough to cause pervasive mold growth in the home, here are the top 3 sources of mold that we see working in the high desert of southern Idaho.

Ventilation Issues

Although Idaho’s humidity levels are not normally high enough to cause mold growth (30-40% during the summer in Boise, although it can be higher in the winter depending on precipitation) poor ventilation can lead to elevated humidity levels quickly in a building. The places we see this occurring most often are: Attics: When there is not adequate ventilation in the attic space it can lead to raised humidity levels. Humidity levels above 60% will lead to mold growth, typically on the roof decking but sometimes on the attic trusses as well. Bathroom ventilation fans that are not properly ducted outside or that have become disconnected can exasperate this issue by pumping humid air from the bathrooms and kitchen directly into the attic. Roof leaks will also cause isolated areas of damage from rain and snowmelt. Crawlspaces: Similar to attics, when there is not adequate ventilation it will often cause the humidity levels to rise until mold is able to grow. Rim-joists are particularly susceptible to mold growth as warm crawlspace condensates on the cold rim-joists. Additional moisture can originate from the soil, especially if there is not a proper vapor barrier installed.

Plumbing Leaks

All mold needs to grow is a food source and moisture. So anytime we’re dealing with a plumbing leak chances are mold will find a food source. No matter the climate plumbing leaks and water damage will unfortunately be a reality.

Wet Construction

Even if there aren’t any current or active moisture issues in your home, mold may still be present due to the home being built in wet conditions. If the structure or lumber becomes wet during the building process and is not dried out properly before being buttoned up, mold will likely grow. Most often this will occur in the crawlspace where wet lumber has a more difficult time drying out.

While we may not deal with the same issues as more of our more humid neighboring states, Idaho still has plenty of moisture for mold to thrive. Having your home regularly inspected will help prevent issues from becoming worse or future issues from occurring. Preventative maintenance is often your best weapon against mold and keeping your home healthy. Don’t wait until it’s too late!

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