VAPOR BARRIER INSTALLATION IN SEATTLE

Attic Projects Company is one of Seattle’s top crawl space encapsulation contractors. Our goal is to prevent natural moisture from affecting your home’s structure. We use commercial STEGO wrap, which is made from a synthetic, nonporous material. Our installers will cover your crawl space, and we offer a 10-year warranty on labor and materials.

Why Seattle Homes Need Moisture Protection Underground

Proper pest control in the Seattle area starts with sealing your crawl space. A moisture barrier eliminates the entry points that rats, mice, and other pests use to access your home. Once installed, barriers reduce the need for chemical pest control treatments and give your home a long lasting physical barrier against infestations. By blocking moisture and sealing access points, this system supports long-term rodent control and helps prevent future rat and mouse infestations.

• Moisture Barrier to Control Moisture
• Protective Sheeting to Limit Condensation
• Crawl Space Liner to Prevent Rodents
• Crawl Space Cover to Prevent Mold and Mildew
• Moisture Protection to Prevent Condensation

If mold has already developed, our Seattle mold remediation team eliminates existing growth before barrier installation.

How to Select the Right System for Your Property

Understanding Vapor Diffusion and Permeability

A moisture barrier, technically known as  vapor diffusion retarder, is designed to slow or stop the movement of water vapor through porous surfaces like concrete and wood. The effectiveness of a barrier is measured by its permeability rating, which indicates how much moisture can pass through the material. We use low-permeability materials (typically 10 mils or thicker) that are highly resistant to vapor diffusion. This ensures your crawl space stays dry regardless of Seattle’s weather conditions or seasonal changes in humidity and groundwater levels.

Standard vs. Chemically Treated Polyethylene Sheeting

While many contractors use standard plastic sheeting, we often recommend non-toxic chemically treated, reinforced polyethylene for crawl spaces with high moisture levels or concrete floors. This material is resistant to the abrasive properties of concrete and provides protection against soil contaminants and groundwater. It acts like a shield for your foundation, preventing moisture while also resisting punctures, tears, and degradation over time. The chemically treated surface also inhibits mold and mildew growth on the barrier itself.

The Importance of an Integrated Air and Vapor Barrier System

For energy efficiency and structural integrity, a crawl space encapsulation system should be part of a system that also controls air leakage. An air barrier controls the flow of air in and out of your crawl space and building envelope. When combined with a moisture barrier, this approach reduces heat loss, improves the thermal performance of your home, and minimizes the risk of water intrusion from both liquid water and water vapor. The result is a more efficient home, lower utility bills, and durability of your foundation and structural components.

Seattle homeowners typically notice lower energy bills after vapor barrier installation. By reducing moisture in the crawl space, your HVAC system runs more efficiently and your insulation performs as designed by the manufacture. Over time, the energy savings help offset the cost of installation while keeping your home comfortable.

Vapor barrier installation is the first step in crawl space encapsulation. While full crawl space encapsulation may include dehumidifiers and drainage systems, the barrier provides  protection against ground moisture. For Seattle homes with moisture problems, we can design a complete encapsulation system around the vapor barrier to address all sources of water intrusion.