Mold Growth

Mold growth in buildings occurs when fungal spores, which are naturally present in all indoor and outdoor air, find suitable conditions to germinate and multiply. The three requirements for mold growth are moisture (relative humidity above 70 to 80 percent at the material surface), a suitable temperature (5 to 40 degrees Celsius, with optimal growth at 20 to 30 degrees), and an organic nutrient source (wood, paper, dust, or even the paper facing on gypsum board).

In Finnish buildings, mold growth is almost always caused by a moisture problem — either water infiltration, condensation, or inadequate ventilation. Common locations include poorly ventilated bathrooms, behind furniture placed against cold exterior walls, in crawl spaces with inadequate vapor barriers, in attic structures where moisture has penetrated past the vapor barrier, and in any area affected by plumbing leaks or water damage.

Mold produces volatile organic compounds (the characteristic musty smell) and releases spores and other bioactive particles into the indoor air. Exposure to mold can cause a range of health effects including nasal congestion, coughing, wheezing, eye and skin irritation, and in sensitive individuals, more severe allergic or asthmatic reactions. Finnish health authorities take mold exposure seriously, and confirmed mold damage typically requires professional remediation.

If you discover or suspect mold in your building, do not attempt to clean it yourself with bleach or other household chemicals — this treats the surface without addressing the underlying moisture problem, and disturbing mold can release large quantities of spores. Instead, arrange a professional moisture survey to identify the moisture source, followed by a remediation plan that includes eliminating the moisture problem, removing mold-contaminated materials, drying the structure, and verifying successful remediation through post-cleanup testing.