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HVAC

Prescription for Mold Prevention

Every year tremendous physical damage and financial loss to structures are caused by natural catastrophes such as hurricanes, storms and overflowing rivers, and by building related flooding from water pipes, fixtures, appliances, construction defects and maintenance issues. Water flows horizontally, downwards due to gravity, or wicks up into porous materials by capillary action. Water can cause buckling of hardwood floors, delamination of adhered materials, swelling of sub-flooring and damage to ceilings and walls.

When sudden water intrusion occurs in a building, it is usually noticed by building occupants. This offers an opportunity to correct problems and dry materials quickly. Immediate action, appropriate planning and selection of equipment, and careful monitoring are needed to protect building materials and contents from further damage caused by fungal growth. The plan should consider water pathways and concealed spaces where drying might need to be assisted. The time elapsed from the start of the event will determine the approach – removal versus drying. If moisture is allowed to remain in wall or building cavities that contain organic materials for more than a few days, hidden mold growth is likely to result. Hidden growth can be very difficult to locate once surrounding materials have dried out, and remediation of hidden growth can be very costly to remedy. An appropriate response to water entry will minimize damage and cost.

Water is the single most important factor for microbial growth in indoor environments. While water intrusion will not result in immediate mold growth, measurable growth can occur quickly. Laboratory studies have shown that fungal growth can occur within 28 hours after spores become wet. Some common species are able to grow in less than 48 hours. Even where materials are not physically wet, flooding can elevate the relative humidity which in turn can elevate the moisture on materials to a sufficient level to promote mold growth. Therefore, restorative drying contractors typically attempt to have buildings substantially dried within 48 to 72 hours of a water intrusion. Based on our field observations, mold growth on wet building materials is usually visible to the unaided eye within one week.

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