Renovating often involves some new construction such as the addition of a room or wing. New construction provides an opportunity to install a continuous air and vapour barrier and high levels of insulation in an efficient and cost-effective way.

Figure 7-12 shows a typical cross-section of new construction from the roof to the footings. Note how both the insulation and air barrier run continuously without breaks or thermal bridging.

Renovations also allow for current or future allowances of renewable energy and other energy-efficient features into your home such as solar water heating, passive solar heating, radiant-ready in-floor heating and photovoltaic power generation.

Attic

High levels of insulation, a continuous air and vapour barrier and ventilation are the features of an energy-efficient attic. Roof trusses are available that allow high insulation levels above the top plate of the outer walls. These include raised heel trusses for flat ceilings, scissor trusses for cathedral ceilings and parallel chord trusses for flat roofs.

Walls

The section in the illustration at the right shows a 2 x 6 wall with insulating sheathing. Other wall systems include interior cross strapping, double-wall systems and the use of trusses. These systems allow the continuous air and vapour barrier part way in the wall. Note the recessed headers that allow room for the continuous air and vapour barrier and extra insulation.

Windows

High-performance ENERGY STAR® windows are used where possible. Most windows face south. All windows are sealed to the air barrier.

Foundation

The foundation has full-depth insulation - in this example, on the exterior. Proper damp proofing, a drainage system and a sloped grade help ensure a dry basement.

Mechanical systems

Space heating and cooling systems are smaller for well-insulated and air-sealed homes. High-efficiency space and water heating equipment can use directly connected combustion air and avoid using household air to operate.