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Mason General Hospital Addition

NEXUS was involved in this addition to the existing Mason General Hospital in Shelton, WA. This 60,000sf, two-story addition increased the size of the hospital’s building envelope by an approximate 88,000sf. Our team provided services during the pre-construction, construction, and testing phases to ensure the owner’s building envelope energy and performance requirements were met.

As the building envelope consultant, NEXUS performed an independent technical review of the air barrier design documents for compliance with the 2015 Washington State Energy Code (WSEC). This review included practical recommendations and allowed for successful air barrier transitioning to occur at critical junctures which included where the new building meets the old.

During construction our team worked with the Construction Manager and General Contractor to review the installation of the air barrier for design document conformance. Prior to award of the certificate of occupancy, NEXUS performed building envelope air leakage testing. This test of the addition verified the performance of the designed and constructed air barrier. Following the air leakage test, infrared thermography was utilized to identify areas of air leakage throughout the building. As a result of our involvement and the project team’s proactive efforts, the tested maximum allowable leakage rate was substantially lower than the 2015 WSEC requirement of 0.40 cfm/sf and even lower than 0.25 cfm/sf leakage rate identified in the prescriptive pathway for the Washington State Energy Code.

Project Summary


Mason General Hospital


Independent Technical Review, Installation Observations, Window Water Penetration Testing, Whole Building Air Barrier Testing


Shelton, WA

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