Headlands observatory: A wall system case study

How the Ultra Air Barrier Wall System overcame winter-time challenges

It would be a safe bet to assume that any contractor entering winter along the Straits of Mackinac in northern Michigan considers the weather as a significant barrier to staying on schedule. For the Construction Manager, Spence Brothers and the mason, Straus Masonry, a bit of clever design for enveloping the structure, backed by building science, kept construction of the Headlands International Dark Sky Park’s new observatory on schedule as weather conditions threatened progress.

The brand new Headlands’ observatory features a large visitor center and also a partially circular tower to maximize star gazing. The park itself is a 600-acre parcel of old-growth forest situated on more than two miles of undeveloped Lake Michigan shoreline at the northwest tip of Michigan’s Lower Peninsula, where the Straits of Mackinac sweep into the lake. The estimated 35,000 annual visitors – sky gazers – find the darkest of skies, undiluted by light pollution. Construction of the observatory began in November 2015 and continued through 2016 and into 2017.

For the main visitor center Spence Brothers chose to use Dow’s Ultra Air Barrier Wall System to insulate and protect the building envelope, favoring the system’s ease and speed of installation, as well as the ability to reduce sequencing complications that arise from spray foam insulation. The system, supplied by Masonpro, combines moisture protection and thermal performance in one integrated package. It consists of STYROFOAM^™ Brand CAVITYMATE^™ Ultra for continuous rigid insulation with an integrated water barrier and GREAT STUFF PRO^™ Gaps & Cracks insulating foam sealant to seal against air and water penetrations between insulation seams and wall penetrations.

“I was satisfied that our masons could install both the system, which doubles as insulation and waterproofing, quickly after the CMU block was up,” said Bill Frederick, Superintendent of Spence Brothers, whom oversees the project. “Dow’s Ultra Air Barrier Wall kept us on schedule and addressed our concerns regarding using spray foam in high wind environment potentially getting overspray on finished surfaces”.

Plans for the circular observatory originally specified spray foam insulation as a monolithic, conforming layer typically ideal for rounded tower structures. However, the forecast continually called for high winds, cold temperatures, with rain and snow which threatened costly delays and also the scheduled grand opening in June 2017. 

For a majority of the project, Dow’s Ultra Air Barrier Wall System – comprising 15¾-inch x 96-inch rigid insulation installed horizontally – and it was assumed to be unsuitable for the rounded observatory portion. Eager to find alternatives and eliminate the concerns around the weather delays for the spray foam insulation Jason Chapman of Straus Masonry and Bill Frederick of Spence Brothers contacted Ryan Gerulski, Dow’s building science consultant. Straus Masonry, Spence Brothers, and Ryan devised a clever alternative to spray foam that would allow the project to remain on schedule regardless of weather conditions, avoid further delays, and provide a high performing building envelope to the owner. Straus Masonry installed the Ultra Air Barrier Wall System on the rounded wall, but flipped the boards 90 degrees vertically and proceeded to fill the joints with GREAT STUFF PRO^™ Gaps and Cracks.

This solution allowed an on-time completion of the job, on all exterior wall segments regardless of circumference. It also allowed construction to continue during harsh weather conditions and in the end a system that delivers high thermal performance protection against moisture in the wall enclosure. Visitors began to enjoy the sights from the new observatory since the grand opening in June 2017.