Mold presents a major health risk to your family, and the moist, dark conditions of the average basement provide the ideal environment for mold growth. Wise renovators look for products and installation methods that help to reduce the risk of mold in a basement renovation, creating a healthier environment for all. Whether you are updating an older home or finishing the basement in a new build, creating a mold-free space can be a challenge.
Why Does Mold Grow in the Basement?
Mold spores float around your home, both inside the walls and outside. When those spores collect and multiply on surfaces, toxics and allergens are released triggering reactions or illness. Basement rooms, surfaces and furniture tend to present ideal growing conditions for mold — moist and dark — which makes this area especially important.
Mold feeds on organics, such as paper, wood, plants and natural fibers. Certain elements commonly found in basements contain organics, including:
How to Reduce the Risk of Mold in Basements
Include mold resistant building materials in your basement renovation to reduce the risk of mold growth. Think about how you can substitute organic materials (wood, paper, natural fabrics) with other materials (metal, plastic and synthetic fabrics). You need to maintain a comfortable atmosphere without providing mold with an abundance of organics to feed on.
Avoid storing cardboard boxes in the basement, as well as other organic materials. Opt for plastic, metal or well painted shelving.
Another way to reduce mold growth is by improving air flow. Mold spores multiply when left undisturbed for a decent length of time. Movement, especially air flow, disturbs the spores and halts growth. Ventilation is key in any basement renovation.
Sunlight also helps to warm up the space and kill off the growing spores. Mold does not generally spread in well lit areas. Consider installing additional or larger windows to let the maximum amount of natural light into this space. Using top quality windows will help improve insulation values, but it helps to choose styles that can be easily opened for air flow.
Creating Superior Ventilation
All bathrooms and moisture-producing appliances (laundry, stoves) need to be fitted with an exhaust system that vents to the exterior of your home. Do not run the vent pipes into the attic. Use affordable, durable venting solutions to direct moist air out of your home. This principle is true on any floor of your home, but it's especially vital in the basement.
Fresh air vents bring in outdoor air through the HVAC system, facilitating air flow. Design your basement renovation to include a fresh air vent in every room — bedrooms, bathrooms, offices and family rooms. Check out local building codes to ensure your floor plans follows the applicable standards regarding fresh air vents.
Keep Humidity Levels in Check
Humidity levels tend to be higher in the basement, and that moisture leads to mold growth. Invest in a dehumidifier (standalone or within your HVAC system) to keep the humidity low.
Relative humidity within your home should land between 30 and 50 percent. Mount a humidity meter in the basement to get a quick gauge on this number, and use your dehumidifier on a regular basis. Look for an Energy Star rated model to maintain reasonable energy consumption as well.
Sealants and Vapor Barriers
Moisture naturally seeps through concrete and other porous substances. Most basements are encased in a concrete foundation, and sealants must be applied to reduce the amount of moisture coming into the space.
Consider sealing the concrete subfloor before installing any underlayment or flooring products. Use a good quality product offering complete coverage, and remember to fill any cracks in the concrete before applying sealant.
Put up a layer of poly vapor barrier (around 6mil works) between the wall framing and foundation wall. Seal the poly at the floor and ceiling, and at every seam, to ensure that moisture cannot reach organic materials inside your home, such as framing and drywall.
Some sealants combine thick coverage with a tint to provide a one step finish for cinder block basements. If this works for your home, take a look at products like Drylock, providing a fairly decent barrier against moisture that naturally passes through porous cinder blocks.
Alternative Building Materials
Some people opt for stainless steel framing or use a treated wood suitable for interior use (such as BluWood). If the basement renovation budget allows, installing these alternative products should reduce the risk of mold substantially.
Think about the exterior of your home as well. You may not have considered landscaping part of the basement renovation, but in order to keep mold away you will need to deal with drainage issues.
Does the grade slope away from your home to direct water away from the basement? Would a French drain or improved swale help to reduce the water level? Have a professional landscaper assess the drainage and plan to make the necessary improvements as soon as possible.
Cleaning Up Existing Mold
If you currently have visible mold in your basement be sure to remove the spores before enclosing the space. Small amounts can be washed away with a diluted bleach solution, but larger amounts may require the attention of a professional mold remediation specialist.
Visible signs of mold need to be dealt with, but certain types of mold are not visible. Some are detected by smell, while others grow in hard to reach places. Mold testing can be conducted on air samples to determine whether mold currently exists in your basement.
Reduce the risk of mold by planning your basement renovation well. Consider ventilation and air flow, natural light and building materials. If mold currently exists, have it completely removed, and apply a sealer to concrete foundations to block moisture seepage. Value the health of your family by tackling the mold risk while renovating the basement.