Indoor Mold and Other Indoor Air Quality Issues

The importance of indoor air quality.
Indoor mold and other air quality issues deserve more attention today than in prior years. With home heating and cooling costs on the rise, and the likelihood that they will continue to rise, designers and builders are challenged to produce energy-efficient, air-tight homes. Because of this, indoor air quality issues are more important than ever. Even in large industrialized cities the air within our homes can be more polluted than outdoor air. Research suggests that people spend most of their time indoors, especially during the winter months. Here we discuss mold, radon, formaldehyde and organic gasses.

Indoor Mold:

Mold is a natural part of our environment both indoors and outdoors. Indoor mold only becomes a problem when mold spores find a damp surface indoors and begins to grow. As long as the moisture remains the mold can survive and thrive especially on cellulose based (wood, paper, boxes etc.) surfaces. If you suspect you have indoor mold consider the following:

  • Have your home tested for indoor mold.
  • Find and fix the any leaks or moisture problems
  • Provide proper ventilation in bathrooms, kitchens and basements.
  • Keep the relative humidity in your home below 60%.
  • Small areas of indoor mold can be cleaned with warm water and detergent.
  • Wear a mask to avoid breathing spores.
  • Wear non-vented goggles to avoid getting mold in your eyes.
  • Wear gloves when working with mild detergents.
  • Avoid spreading indoor mold to other areas of the home.
  • Clean and repair gutters regularly.
  • Make sure the ground slopes away from your foundation.
  • Keep a/c drip pans clean and drain lines unobstructed.
  • Call in a professional mold remediator for areas of indoor mold larger than 10 sq.ft.


An odorless, naturally occurring radioactive gas that is heavy and accumulates in lower levels of homes, and well water (in much of New England). Radon gas is estimated to cause ten percent of all cancer deaths each year. Smokers are at a higher risk. What can you do?

  • Have your home tested for radon. Do-it-yourself kits make it simple.
  • Seal cracks and other holes in basement floors and walls below grade.
  • Ventilate crawl spaces. Locate vents opposite each other for best results.
  • Install a power vented cover over sump pump basins connected to a stack vented to the outside. In new construction, provide a 12 inch layer of stone before pouring the basement floor, this allows both gases and water to be drawn to the sump basin area before being pumped out.
  • Opening windows is an effective form of natural ventilation during the warmer months.
  • Install six mil polyethylene (be sure to overlap edges 6 inch min) before pouring basement floors in new homes. This helps to prevent gases from leaching through the cement slab.
  • Radon in well water can be treated with charcoal filters. When in doubt, have your well tested.


An ingredient in pressed wood products such as wafer-board, particle board, some paneling’s, furniture cabinetry and other building products. Known to cause eye, nose and throat irritation, coughing, wheezing, rashes, fatigue and other allergic reactions. May also cause cancer. What can be done to mitigate this?

  • Use plywood instead of pressed wood products for sheathing on floors, walls and roofs.
  • Purchase furniture and cabinets made from solid wood or plywood. This furniture may cost more but it is worth it.
  • Avoid inexpensive paneling which is often made from pressed wood products.
  • When you bring new sources of formaldehyde into your home, increase ventilation. Natural ventilation (opening windows) is very effective but not practical in the cold months. Forced ventilation consists mainly of using fans (such as bath fans or range hoods) to move increased amounts of air compared to the volume of movement that naturally occurs. Heat recovery ventilation systems essentially recapture the energy (cold or warm) from air being exhausted before it leaves your home.

Organic gasses:

An ingredient in many household products such as, paints, paint strippers, solvents, wood preservatives, cleaners, disinfectants, air fresheners, aerosol sprays, stored fuels, automotive products, dry cleaned clothing and hobby supplies etc… These are known to cause eye, nose and throat irritation, loss of coordination, headaches and nausea. They may also cause damage to the central nervous system, kidneys and liver. Some may cause cancer.

  • Always use these products according to manufacturers’ directions.
  • Use products outdoors or in well ventilated areas. This cannot be stressed enough.
  • Buy in quantities that will be used up quickly.
  • Store in well -vented remote areas such as, garages, tool sheds and basements. Do not store under the kitchen sink.
  • Dispose of unused containers safely. Some towns offer free disposal once or twice per year. Check local newspapers for periodic listings.
  • Increase natural ventilation during the warmer months.

When building a new home, express your concerns to your designer to enlist his cooperation. He can suggest building materials and furnishings that are low emitting along with recommendations on high tech heat recovery ventilation systems. If you are remodeling an existing home, many of the same tips and techniques still apply.

Home Design Energy GeeksDesign Tip: When installing central vacuums, consider installing the vacuum unit itself on an outside garage wall. This keeps the noise level down. It also makes it easy to vacuum vehicles and empty the unit when full, allowing the exhaust vent to go directly to the outdoors rather than recirculate within conditioned space.

Weatherization / Mold Remediation / Home Ventilation /Blower Door testing / Duct Leakage testing / Radon Mitigation / Custom Building Plans