Eco-responsible basement tips

ENERGY STAR® rated light fixtures consume 66% less energy on average and minimize heat release, which cuts down on air-conditioning needs in summer.

Compact fluorescent bulbs last about 10 times longer than ordinary incandescents and consume 4 or 5 times less energy. Some compact fluorescents can be installed with a dimmer, for greater control over ambient lighting. Because these bulbs contain a small amount of mercury, they cannot be simply thrown away but must be taken to dedicated recovery sites. In the event of breakage, use a piece of cardboard to collect the pieces, place them in a sealed container and dispose of at a recovery centre.

LEDs (light emitting diodes) are becoming more and more affordable, they’re well suited to residential lighting needs (better colour rendering), and they have the potential to consume less energy than compact fluorescent bulbs. Interestingly, LEDs have a very long lifespan – 5 to 10 times longer than compact fluorescents, which means 50 to 100 times longer than incandescent bulbs. They can also be adapted to different configurations – bulbs, strips and panels – to provide ambient or functional lighting. LEDs are not very heat resistant, however, which reduces their efficiency. Unlike compact fluorescents, LEDs contain no mercury or noxious gases.

Dimmer switches adjust the intensity of the light, which increases eye comfort and decreases energy consumption: depending on the decrease in intensity, a zero-resistance dimmer can save from 5% to 50% in energy costs. 

Electronic thermostats produce a steadier temperature: a variation of 2°C is needed to activate an ordinary thermostat, but just 0.5°C is enough for an electronic model. This rapid reaction to temperature fluctuations can generate up to 9% in energy savings (Office of Energy Efficiency).

Programming options allow you to adjust the temperature to the family’s needs and avoid raising and lowering the temperature too often. For example, reducing the temperature by 3°C at night or during an 8-hour absence can lead to energy savings of 10% (Office of Energy Efficiency).

Models equipped with occupant presence detectors don’t require any programming. The heating is activated and deactivated based on the presence of people in the rooms, leading to significant energy savings. 

Casement (or “crank”) windows offer the best airtightness because of their double compressed weatherstripping, which can be replaced if it breaks. Hanging and sliding windows have to slide along the frame, which prevents the use of such high-performance weatherstripping. The airtightness of newer window models has improved remarkably, however, and adding a plastic film in winter allows them to achieve efficiency similar to that of a casement window.

Special attention needs to be paid to basement windows: The window well should be below the level of the window, filled with gravel and equipped with a drain connected to the French drain, to allow water to drain quickly. 

Unfortunately a basement is never completely safe from water infiltration, so durable, waterproof, easy-to-clean materials (like linoleum) are a must in basement renovations.

Avoid carpets. Since they’re hard to clean and hard to dry, they can easily become a source for mould. Use adhesives with no volatile organic compounds for tiles and other floor coverings. Many highly effective ecological products are now available on the market. 

Radon is heavier than air and can accumulate in the basement after seeping in through foundation cracks. A detection test may be useful before undertaking repairs, especially if you live in an area where high concentrations have already been detected.

Several methods can be used to prevent or at least reduce the accumulation of radon in the home: active or passive ventilation under the concrete slab, ventilation of entry points, installation of an air exchanger or sealing the house. To ensure your anti-radon measures are effective, consult with an expert.  

Install a high efficiency central ventilation system suited to the size of the space to be aired. The system’s air intake and outlet must be located outside the home to reduce the health impact. To save energy, choose a heat recovery ventilator (HRV) that is certified by the Home Ventilating Institute or ENERGY STAR®, rather than a conventional model. Certified models are also quieter, which encourages their use. Avoid ducts that are too long or too flexible as this will reduce the system’s performance.

Effective air circulation in the basement can help evacuate excess humidity. Install air recirculation units in all basement rooms to keep air and heat circulating. Humidistats are a practical solution for this: they automatically turn on the fan when the relative humidity level gets too high.

The growth of mould and its impact on health can be minimized by controlling humidity. If the ventilation system does not adequately eliminate excess humidity, install an ENERGY STAR® dehumidifier suited to the size of the rooms. Mould and mildew form mainly in damp places like bathrooms and basements, so in these areas you need to take certain steps for the sake of your family’s health.

Use paints and primers labelled “VOC-free” or “low emissions” to protect your health. Although alkyd paints (oil-based) last longer and create a shinier finish, they contain a solvent thinner and are not usually as good a choice as latex (water-based) paint in terms of health. Read labels carefully or select products with an EcoLogo™ or Green Seal™ label. 

Fly ash from the combustion residue of coal-fired power plants is an example of the kind of recycled product that can be added to concrete to replace part of the cement, reducing GHGs. Mixtures containing from 15% to 25% fly ash are available on the market.

Some kinds of concrete are made from aggregates (gravel, sand, glass, dust) recycled in the region where the concrete is used, which reduces resource waste and minimizes waste production.

Small cracks (narrower than a pencil) can be fixed from the inside using a waterproof grout sealer.

Larger cracks need to be fixed from outside by excavating around the foundation walls all the way to the footing. At the same time, you should apply water resistant insulation to the outside walls to reduce heat loss.

If the cracks are quite large or seem to move, consult a structural engineer to determine the best way to repair them. 

Make sure your perimeter foundation drains (French drains) are working well. They must not be obstructed or lower than the bottom of the concrete slab. Drainage systems generally have a lifespan of 30 to 40 years. Pay special attention to their condition, because ineffective drainage can lead to major problems in the home over time.

Make sure your downspouts direct rainwater well away from the home. One good strategy is to install rain barrels: they can also help you save water for the garden and lawn or washing the car.

Inside the home, the drainage system should include a cleanout trap and a check valve (backwater valve) to protect the basement and the foundations.

Insulation saves energy and reduces GHG emissions, but to be effective, it is especially important to reduce air leaks and heat loss by installing the right insulation in the right place. Attics, walls, floors and foundations all have their own specific requirements, based on their structure and exposure to humidity. No matter where the insulation is being installed, you should always choose the one with the highest R or RSI value.

If the concrete slab has to be re-poured, install a layer of rigid insulation panels underneath, as well as a polyethylene membrane.

If the concrete slab is not insulated from the outside, installing insulation inside under the floor covering will keep the basement warmer and dryer.

Adding a subfloor is especially important if the concrete slab lies directly on a gravel bed. First cover the concrete with a polyethylene membrane before laying down joists and plywood. Choose low-emissions wood products from certified forests.

Installing cladding and insulation on the outside of the foundation walls is the most effective way to reduce humidity. Since foundations have to be accessible to insulate them this way, your best bet is to plan this to coincide with excavation work.

After ensuring there is no infiltration and no trace of dampness on the walls, apply spray polyurethane foam. Instead of spray foam, you can also use insulation panels fastened to the walls or batts tucked between the wall studs. In this case you will also need a vapour barrier on the warm side of the insulation.

Choose water resistant drywall or cement backer board with metal studs, rather than wooden ones, to prevent the proliferation of mould, especially if you have trouble controlling the dampness in your basement.