Moisture control is a key component in building design, especially for walls. Without it, moisture infiltration is likely to occur which can lead to rot, mold and other problems.
The design of enclosure systems must incorporate redundancy of control functions and the use of multi-functional materials. These materials must also be properly installed and sealed around penetrations such as plumbing and electrical.
Insulation
Insulation is a key component in building a more energy-efficient home. It reduces air leakage and helps prevent thermal loss, which can increase your energy bills significantly. It also helps protect against mold and mildew growth, which can negatively impact occupant health. Traditionally, insulation materials have been associated with environmental concerns, but new, sustainable options are available that address moisture control while minimizing their impact on the environment.
In climates where condensation is a concern, it’s important to use insulation and smart vapor barriers to prevent warm indoor air from reaching cold surfaces within the building envelope. This will prevent the formation of frost and ice. The best choices for this type of climate include fiberglass insulation and a vapor barrier.
Other insulation options include pipe wrap insulation, which can be wrapped around pipes of various sizes and shapes to offer good thermal insulation as well as moisture resistance. Cellulose insulation, made from recycled paper products and treated with fire retardants, is another option that offers superior moisture control. It can absorb and release moisture as needed, regulating humidity levels and preventing condensation.
Many homes are under-insulated, wasting money on heating and cooling and exposing your plumbing to temperature changes that can lead to expensive repairs. Adding proper insulation, combined with air sealing, can save 15% or more on your annual energy costs. It can also make your home more comfortable and quieter, especially if you have a snoring husband or noisy neighbors.
Air Sealing
Air leakage around the edges of a building envelope wastes energy, increases heating and cooling costs, reduces indoor comfort, and contributes to an unhealthy living or working environment. It also allows moisture, drafts, and outside noise to enter a building.
To minimize energy loss, insulation and air sealing must work together. Insulation is placed where it can directly contact the building’s air barrier, which may be the sheathing and drywall on exterior walls, the sub-floor and foundation, or the attic ceiling and roofline.
Regardless of the type of insulation installed, it should be air sealed with products like foam sealant and caulk to maximize its effectiveness. For example, when spray foam insulation like RetroFoam is applied in the attic, it fills every crack, gap, and nook to create a strong air seal in the wall cavity.
The tighter a home or commercial structure is, the lower its energy bills will be. A tight envelope also reduces temperature differences between rooms and minimizes moisture infiltration, which helps prevent condensation, mold, and rot. In humid climates, a tight envelope can reduce the infiltration of outdoor pollutants, allergens, and dust, which improves indoor air quality. It can also prevent the infiltration of moisture-laden outdoor air, reducing the occurrence of mold and mildew in wall cavities and attics.
Ventilation
Moisture can erode wood and metal building materials over time, leading to costly problems like rot and mold. Proper ventilation can mitigate moisture accumulation and help ensure long-term durability, comfort, and performance. Ventilation strategies, when coupled with effective air sealing and insulation, can make structures more energy efficient, less expensive to heat and cool, and healthier for occupants.
Most moisture movement in walls happens through air currents, capillary action, or condensation. Insulation decreases thermal bridging and moderates temperatures, so it has a direct impact on moisture content in wall cavities. EPS and XPS insulations, for example, both have low water absorption and release vapor more quickly than most other insulation materials. This makes them a good choice for homes with air leaks.
Air circulation is also important to reducing the presence of moisture in walls and ceilings. This can be accomplished through the use of ducts and ventilation fans that extract stale indoor air, introduce fresh air, and maintain appropriate humidity levels.
During construction, ventilation can be optimized by opening windows and using architectural features to promote natural circulation of air. This can also be done through ductwork and HVAC systems to maximize airflow, which promotes the evaporation of moisture and aids in drying damp surfaces. Moreover, by exchanging moist interior air with drier outdoor air, proper ventilation prevents excessive condensation and moisture buildup, preserving structural integrity and enhancing the lifespan of building materials.
Moisture Control
Moisture control is a critical component of energy-efficient, durable and safe building envelope solutions that reduce maintenance and repair costs. It prevents cladding failure and protects the health of occupants by mitigating microbial growth and reducing allergies.
Insulation is an important component of moisture control, since it decreases the transfer of heat and moderates temperatures, preventing condensation on walls and ceilings. Vapor barriers and vapor diffusion retarders are also helpful in decreasing humidity levels, as well as preventing unwanted water retention.
The effectiveness of insulation for moisture management depends on climate and the enclosure design. For instance, coastal areas prone to floods require effective rainwater drainage and flood-resistant construction materials. For northern regions susceptible to snow and ice, adequate insulation and roof designs are essential to mitigate damage caused by ice dams and snow melt.
Air circulation is another key to effective moisture control. Ventilation systems draw stale indoor air out of the home, introducing fresh air and preventing stagnant conditions that lead to mold growth. HVAC system ductwork can be sealed and insulated to improve airflow and temperature control, reducing the occurrence of moisture buildup.
Humidity in buildings can accelerate fungal decay and rot, as well as cause metals to corrode. It can also cause a host of health-related issues, including upper respiratory symptoms. Proper moisture management can help protect occupants, preserve building integrity and increase comfort, while also promoting sustainability and increasing property value.