Basements are notorious for being damp, dark, inhospitable places—the antithesis of what we like to associate with green and healthy living. As a rule, the basements in older homes were not designed to be functional living spaces. Yet for many of us, the basement represents potential bedroom, recreational or home office space at an affordable cost.

While some basements are unsuitable as living space, others can be transformed as long as some “green building science” principles are followed. The following is a partial list of things to consider:

• Test for radon, lead, mold, asbestos, and moisture at the outset and at the end of the renovation to help identify and subsequently rectify pollutants and problems that could impact your health or that of your family.

• Make certain that gutters and down-spouts are cleared of debris and diverting water away from the foundation, and that there is proper grading or slope next to the house. Seal cracks in foundation walls and consider installing exterior water-management controls. Interior waterproofing as a primary or sole means of long-term water management is unreliable. Combined with other measures discussed here, however, it can be useful.

• Building scientists frequently recommend that basement walls be insulated, where possible, on the outside using rigid foam or a similar material, and that they dry towards the interior; the use of a dehumidifier is important. Avoid products like vinyl wallpaper, which can trap moisture inside the wall, leading to mold and structural damage.

• Have a thorough energy analysis done of your home to determine where air leakage is occurring. Air seal as needed.

• Install materials and products that are mold and moisture-resistant, such as paperless (a.k.a. mold resistant) drywall, hard-surface flooring, and insulation that is non-water sensitive.

• Ensure that proper drainage techniques, such as flashing, are installed for all windows and doors.

• Sufficiently ventilate and dehumidify, especially in the summer. Leave basement windows closed during the summer when humidity is high. Consider adding mechanical ventilation to improve air quality. Use an ENERGY STAR rated dehumidifier.

• Add energy-efficient lighting, such as CFLs and/or LEDs. Use occupancy-sensors and timers to reduce unnecessary energy use.

• Improve indoor air quality by using products that are free of formaldehyde and any VOC (volatile organic compound). This includes paint, particleboard, MDF, insulation, flooring, furniture, cabinetry, and wood finishes, among others.

• Consider upgrading to a closed-combustion, high-efficiency water heater, furnace, and air conditioner. If replacing the furnace with a high efficiency version, take care not to “orphan” the water heater—it may have a hard time venting up the chimney by itself, potentially backdrafting CO₂ into the home, along with moisture. You’re better off simultaneously replacing both mechanical systems with closed combustion versions.

Select a contractor who is trained and experienced in green-remodeling. Look for companies whose personnel are trained on the MN GreenStar standards and in building performance and building science. Registering and certifying your project through MN GreenStar is a particularly good way to ensure that healthy, green remodeling practices are followed.