Living in the wet Pacific Northwest, mold grows with reckless abandon. It only needs moisture, moderate temperatures and a food source to grow. In the outdoors, mold is necessary to breakdown dead, organic material. Unfortunately, however, it isn’t really too picky about where it lives. If we are not careful, mold invades our homes.
Without an active moisture source, mold will stop spreading. At the same time, mold spores can lay dormant for long periods of time until the right conditions are present … and crop right up again. Since we can’t get rid of mold completely, we should make every effort to control it in our living spaces.
Mold survives on anything organic such as paper, cardboard, wood, under carpets, leather or even the old cheese in your refrigerator from Adam’s bar mitzvah.
Heath issues associated with prolonged exposure, especially for young children, the elderly and those with respiratory issues are already well documented in the media and medical community. Listed below are some common household areas where mold can be found:
Bathroom mold: The high humidity levels generated from showering and bathing, causes mold growth anywhere dust and/or dirt accumulates. Over time, caulking along the corners and base of the shower will discolor and become moldy. When grout sealing has been neglected, cracks develop in the mortar between the ceramic tiles. This allows moisture in behind the walls, through the cracks by way of “capillary action.” Over time, the moisture can’t escape, so it builds up, resulting in mold growth. Most people are unaware of this until the tiles become loose, it smells musty or they renovate.
Prevention: Always run the fan before, while and after a bath or shower for at least 45 minutes. You can monitor the humidity levels by purchasing a hygrometer. In our environment, you want to keep it 55 percent or lower. In addition, remove your wet towels, clean all dirt, dust and debris. Replace all discolored caulk, while sealing the grout lines.
Attic mold: This type of mold is usually due to poor ventilation. In winter, when the temperature on the attic sheathing is cold, condensation forms. Left unchecked, mold will eventually damage the sheathing. Other notable sources result from roof leaks and air leakage.
Prevention: Ensure the attic hatch is properly weather stripped and insulated to prevent air leakage. Topping up the insulation level to an R-Value of 40-50 is also recommended. All bathroom and laundry vents should be insulated and vented through the roof, not discharging inside the attic. In addition, baffles should be installed along roof edges. Roof or ridge vents allow the air to escape. Roof leaks should be prevented through annual inspections and repairs.
Basement and crawlspace mold: Common in homes that are poorly sloped, missing waterproof membranes, have broken drain tile or foundations cracks. All of these conditions contribute to moisture ingress, resulting in mold. Often people store old furniture or cardboard boxes in the basement for years. As the moisture develops the mold grows, often ruining photos, documents or paperwork.
Mold grows on the structural wood members when the home (usually older) has been built on a dirt floor. There is an incredible amount of moisture vapor that seeps into the crawlspace from the ground below. In addition, ground water can spill into the crawlspace where there are voids along the outer perimeter or cracked foundation wall. Over time, the accumulation of mold can compromise the structure of the home. In addition, these spores can migrate up into the living space through small voids, causing indoor air quality issues.
Prevention: Call a drainage company to scope the perimeter drainage to determine its condition. If damaged, replace older clay, concrete or plastic corrugated drain tile with the modern PVC drain pipe. (This can be expensive) At the same time, seal all cracks and have a proper moisture barrier installed. Place drainage stone around the perimeter, while keeping soil and trees away from the foundation wall.
Completely seal dirt floors with a heavy-duty vapor barrier. Concrete walls should be insulated to reduce moisture. Depending on the water issue, a sump pump may be needed. According to modern best practices, exterior vents are not recommended in crawlspaces, as they should be conditioned (heated). Have the vents covered when possible; install weather stripping and a properly sealed door to the crawlspace as well.
Kitchen mold: This type of mold is usually found under the sink, behind the refrigerator or near the dishwasher, walls and ceilings. These areas are common because small leaks often go unnoticed. Poor ventilation while cooking contributes to indoor humidity issues.
Prevention: Periodically check under the sink, along the floor by the refrigerator and dishwasher for leaks. Clean and caulk around the sink, seams and corners to reduce water damage above and below the counter. Always be at home when you run the dishwasher to catch any leaks. Use the kitchen fan while cooking.
Window and surface mold: Is commonly found on windows sills and frames. When dust and dirt accumulates, in combination with the moisture from window condensation, mold grows. Ceilings, exterior (outside) facing walls, closet walls, or surfaces near kitchens and bathrooms should be examined for signs of mold.
Prevention: If the budget allows, I recommend replacing metal-framed windows with vinyl. Because windows are always the coldest surface of the home, it is important to keep them warm and dry. Mold and mildew can be cleaned off with a mold remover from your local hardware store, or a simple green solution consisting of one-part vinegar, one-part dish soap to 10 parts water. Mix together in a spray bottle. Continue to clean all dust and dirt, and wipe away excess moisture, especially in the winter.
Remember, the most important part of managing the mold in your home is to identify and remove the moisture source(s) as soon as possible. A certified mold inspector can investigate any mold related concerns. If significant mold growth has been discovered, call a mold remediation contractor for safe and proper removal.
Sean Moss is a professional home inspector with his company Sean Moss Home and Mold Inspections.