basement image ORDon’t let mould and other culprits hurt you.

What’s lurking in your basement can affect your health.

Although it’s true that a finished basement can be the most economical way to add living space to your home, what most homeowners don’t realize is that indoor air quality in the entire home can be seriously compromised by incorrectly finishing a basement.

Here’s why.

Basements in older homes generally have insufficient insulation or they are not insulated at all. Making a basement energy-efficient and comfortable involves insulating the exterior walls.

Unfortunately, this is where the problem starts. If you do not plan for moisture management within the wall and for moisture to escape, you might be jeopardizing your home’s indoor air quality by allowing mould to grow.

Mould can cause eye, nose and throat irritation, coughing and phlegm build-up, wheezing, and shortness of breath. It can also provoke allergic reactions and exacerbate asthma in those with a mould sensitivity.

Four things cause mould growth: mould spores, which are present everywhere; organic material, which is a food source for mould and is found in most building materials; air temperature of 20 to 30 Celsius; and moisture.

Under the right conditions, mould can start growing within 24 hours, according to Health Canada. Removing one or more of its causes will prevent or stop mould growth, which is why proper planning is essential when renovating a basement, a space where moisture and other mould- growing conditions are usually present.

Wall and floor assemblies for basements must be properly planned and constructed if mould is to be avoided.

Unfortunately, basements are normally finished by homeowners and small renovators who don’t have a knowledge of building science. That’s why mould growth occurs.

Mould can be hidden behind walls and ceilings, so it is important to check for its presence anywhere that is damp and especially where water damage has occurred. Look for stains or discoloration of finished surfaces, condensation and a musty odour.

Mould needs to be removed immediately, and in many cases you will need professional help. You can learn more about mould and its remediation at the Health Canada website.

Radon, which can cause cancer, is another potentially serious problem associated with basements, whether or not they are renovated.

Radon is a radioactive gas that has no colour, taste or odour. It forms as uranium in the soil breaks down. Naturally occurring uranium is found everywhere – in soil, in rocks and in ground water supplies such as wells. Gases containing radon can enter your home through a dirt floor, cracks in your foundation, sump pumps and other locations. Because basements are confined spaces, the gas can accumulate to dangerous levels.

According to Health Canada, 16 per cent of lung cancers are caused by exposure to radon, and it is the second leading cause of lung cancer after smoking. In Canada, seven per cent of homes have high radon levels.

Fortunately, radon gas can be removed from a home with a fairly simple extraction system. However, you won’t know if you have a radon problem unless you test for it.

Common air pollutants present in basements, including volatile organic compounds (VOCs), carbon monoxide, dust mites and dust particles, can also affect the air we breathe. In fact, an entire home’s indoor air quality can be compromised because of issues in the lower level, especially because your furnace or air handler circulates the air in all levels including the basement.

Ray NandramWe Canadians spend 90 per cent of our time indoors. That means the quality of air we breathe in our schools, at work and our homes has to be healthy. We may not have control over the air quality at work or school, but at home indoor air quality depends on us.

If you are hiring a renovator to finish your basement, find out what is being proposed for moisture management, mould prevention, radon detection and mitigation, and control of other pollutants.

Roy Nandram is President of RND Construction Ltd.