Insulating a humid attic in Mascouche, QC
Challenge
The attic in Mascouche presented significant issues related to both unsealed air leaks and inadequate insulation, which together created an environment highly susceptible to heat loss and moisture accumulation.
Air Leaks and Thermal Bridging: During the inspection, unsealed air leaks were found at several key junctions, especially around the chimney, and points of entry for cables and pipes. These leaks allow the warm air from the living spaces below to escape into the attic, significantly compromising the energy efficiency of the house. This process leads to inconsistent temperatures within the home. Instead of retaining heat during the winter, the heated air escapes through these leaks, causing the HVAC system to work harder to maintain the desired indoor temperature. This inefficiency directly impacts energy consumption, leading to higher Hydro bills.
Impact of Inadequate Insulation: The existing insulation in the attic was insufficient, not meeting the region's standards in terms of the thermal value R, which measures its resistance to heat flow. Without proper insulation, heat loss through the attic is accelerated, as the insulation layer does not adequately resist the upward flow of warm air. In extreme cases, this can lead to frozen pipes and ice dam formation on the roof.
Moisture Accumulation and Mold Risks: Beyond thermal inefficiency, the combination of unsealed air leaks and poor insulation promotes condensation in the attic space. As warm, moist air from the living spaces rises and enters the cold attic, it cools rapidly, causing moisture to condense on cooler surfaces. Over time, this persistent moisture creates the ideal environment for mold growth. Mold not only degrades the structural components of the attic, like wood and insulation.
Solution
Removal of the Existing Insulation: The process of removing the existing insulation is critical because it allows to identify any hidden issues that may otherwise remain undetected. Old insulation, especially in attics, can degrade over time, losing its effectiveness in providing thermal resistance. Additionally, outdated insulation can hide critical air leaks and moisture damage, which contribute to thermal inefficiency, mold growth, and poor indoor air quality.
In addition, removing the old material reveals any potential mold stains or water damage that may have occurred due to condensation or past roof leaks.
Sealing of Air Leaks: As mentioned before, air leakage is a major source of energy loss in homes, especially in the attic, where stack effect causes warm air to rise and escape through unsealed gaps. This continuous airflow not only wastes energy but also creates uncomfortable drafts and uneven temperature distribution throughout the home.
We utilized ZypFoam spray foam, an industrial-grade polyurethane foam, to seal all identified air leaks. ZypFoam expands upon application. Proper air sealing is a key factor in maintaining a consistent thermal envelope, which reduces heating and cooling loads on the HVAC system.
Installation of High-Performance Insulation: After sealing the air leaks, we proceeded with the installation of TruSoft cellulose insulation, which is known for its superior thermal and environmental performance. Cellulose insulation is treated with borates to enhance its fire and mold resistance. It is an excellent choice for attic insulation due to its ability to conform to irregular spaces, providing uniform coverage without leaving gaps or voids.
We installed the TruSoft cellulose at a 16-inch thickness, which provides an R60 thermal value. By applying insulation at this depth, we ensure that the attic is adequately protected against heat loss during the winter, reducing the home's reliance on heating systems.
