When Poor Ventilation Becomes a Worsening Factor in Water Infiltration
In Laval, a significant event recently highlighted the dramatic consequences that can occur when a building lacks a proper HVAC ventilation system. This incident wasn’t caused by structural neglect or extreme weather conditions, but by the absence of a high-performance ventilation system, capable of regulating humidity and preventing condensation buildup.
At AirGreen, we were called in for an emergency response at a triplex in the Chomedey district, where water infiltration had caused major damage to walls, flooring, and insulation—jeopardizing both the health and safety of the occupants.
The Scenario: Excess Humidity, Uncontrolled Condensation, Accelerated Infiltration
It all began with a small crack in the rear wall of the building, followed by heavy autumn rainfall. With no well-calibrated ventilation system in place, moisture took hold inside the building.
Our technicians observed the following:
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Indoor humidity levels above 75%, even during winter
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No air exchanger installed in any of the units
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Poor air circulation, especially in corner rooms and basements
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Constant condensation on windows, cold walls, and uninsulated ducts
This persistent humidity accelerated water penetration through the existing crack, quickly damaging drywall, laminate flooring, and even some of the structural wooden supports.
AirGreen's Intervention: Restoring Clean Air and Preventing Recurrence
Given the urgency, our team proposed a two-phase intervention plan, aiming not only to fix the consequences of the infiltration, but to completely rethink the building’s HVAC ventilation system.
Here’s what we implemented:
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Installation of two high-efficiency ERV air exchangers with smart control systems
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Full cleaning of the existing ducts, plus insulation of all exposed segments
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Addition of extraction vents in bathrooms, kitchens, and laundry rooms
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Precise airflow balancing for each individual apartment
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Integration of a centralized dehumidification system
Following these upgrades, humidity levels stabilized around 45%, allowing structural repairs to begin in a healthy environment—free of mold and with no further water risks.
Humidity: The Invisible but Dangerous Enemy
1. Humidity Encourages Infiltration
Contrary to popular belief, water doesn’t only force its way in from the outside—a moisture-saturated indoor environment draws and retains water in porous materials. It’s a physical phenomenon amplified by the lack of proper ventilation.
2. Poor Ventilation Exacerbates Existing Damage
Without air renewal, moisture gradually seeps into structural materials. Even a minor leak, when combined with poor ventilation, can become a major source of damage.
3. A Good HVAC System Acts as a Preventive Barrier
A high-performance ventilation system maintains stable humidity levels, prevents condensation, and allows materials to dry quickly after a moisture incident. It serves as an invisible shield against future infiltrations.
AirGreen in Laval: Residential Multi-Unit Ventilation Expertise
In multi-unit buildings, ventilation is often overlooked or under-sized. Our approach focuses on delivering custom solutions for each property, based on:
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Structural and architectural constraints
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Actual occupancy of each unit
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Thermal behavior of the building (cold zones, thermal bridges, etc.)
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Targeted energy performance goals
We work with durable, ENERGY STAR certified products and ensure reliable and long-lasting HVAC installations, even in the most complex configurations.
Financial Assistance Available to Improve Ventilation in Laval
Good news for property owners: several funding programs are available in Laval to upgrade or replace ventilation systems:
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The Rénoclimat program, which applies to the addition of high-efficiency air exchangers
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Municipal subsidies from the City of Laval for rehabilitating older residential buildings
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Hydro-Québec’s LogisVert incentives, when ventilation is integrated into a heat pump or energy retrofit project
AirGreen supports you every step of the way, from technical proposals to grant application submissions, providing all necessary documentation to streamline the process.
Avoiding Disaster Through Preventive Inspections
This situation in Chomedey could have been avoided with a yearly ventilation inspection. These visits help:
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Identify areas with excessive humidity or air stagnation
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Check the mechanical condition of exchangers, motors, and filters
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Ensure airflow balance throughout all rooms
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Prevent mold, slow leaks, and hidden condensation buildup
AirGreen offers tailored preventive maintenance contracts for multi-unit properties across the North Shore, including seasonal visits and adjustments based on real occupancy.
Prevent water infiltration in Laval with well-designed ventilation. Contact AirGreen for a complete inspection and a long-term HVAC solution—starting today.