Mackinac Island, Michigan, is a famous summer tourist destination. The entire island is a National Historic Landmark, with most of its area comprised of Mackinac Island State Park. Motor vehicles are not allowed on the island, and bicycles and horse-drawn carriages give it a unique feel.
Spanning 18 acres of waterfront property on Lake Huron is Mission Point Resort, an award-winning hotel and event space. When Mission Point Resort’s roof needed to be replaced, the roofing system had to serve more than one purpose. A system had to be designed to not only withstand the harsh Michigan weather, but also to handle a large volume of foot traffic, bicycle traffic, and horse-drawn wagons.
Removing the existing roof, a more than 50-year-old mixture of a built-up system, brick, and sand, wouldn’t be an easy task. The only way to access the island is by ferry, and removal of the roofing system would require numerous trips back and forth from the island for disposal. Getting materials to the island would also be tricky and would require multiple ferry trips and horse-drawn carriage rides to deliver the materials.
Work was scheduled to begin in the fall, which made the weather a concern. Average fall and early winter temperatures on the island can range from 18 to 35 degrees, not including the wind chill from Lake Huron. Beating the snow would be a factor.
The Proposal
Mission Point Resort enlisted Doyle Inc. Roofing to install a durable roofing system that would be able to withstand foot, bicycle, and horse-drawn wagon traffic. The company suggested a plaza paver system because it would not only be visually appealing, but also functional and durable.
The proposed roofing system would include two layers of extruded polystyrene (XPS) insulation boards and 80-mil VersiWeld TPO. In areas where the resort’s roof had existing skylights, and due to the height variations, Doyle Inc. Roofing suggested fully adhering Versico’s VersiFleece TPO membrane with Flexible DASH Adhesive directly to the concrete deck.
In August 2018, Joel Ross with Doyle Inc. Roofing, along with representatives from Versico Roofing Systems, began planning the removal of the existing roofing system. At the same time, they started designing the new system to meet the resort’s specific needs. A 900-square-foot test section was installed in May 2019 to ensure the new system met the project’s unique performance requirements.
The existing 50-year-old roof system was removed, which required 16 round-trip ferry crossings to St. Ignace. From there, the material was transported approximately 18 miles back across the Mackinaw Bridge to the designated disposal site.
Deliveries of material for the new roofing system followed a similar process and required 32 round-trip ferry crossings for everything to be delivered to Mission Point Resort’s freight dock. From there, all material was loaded onto horse-drawn drays and wagons to be delivered to the installation site. This process alone took nearly 200 wagon loads.
The Installation
The main roofing section amounted to 23,479 square feet. Doyle Inc. Roofing began with VersiWeld 80-mil TPO loose-laid over two layers of extruded polystyrene (XPS) insulation boards. Versico’s HP Protective Mat was then installed over the 80-mil TPO. HP Protective Mat is a nominal 6-ounce, UV-resistant fabric that is used above the membrane as a slip-sheet for pavers and provides added protection against membrane punctures. Once the HP Protective Mat was in place, approximately 7,100 concrete Sunny Brook Pedestal Pavers were installed. Concrete pavers are an attractive and functional choice for plaza decks and can provide long-term strength and weatherability.
In areas surrounding the skylights, Versico’s 115-mil VersiFleece TPO was fully adhered directly to the concrete deck with Flexible DASH Adhesive. This was a huge benefit for the project, as height variations existed in these areas and having the ability to adhere the membrane directly to the deck allowed the project to move forward efficiently. On the building’s parapet walls, Versico’s VersiWeld TPO Membrane with APEEL Protective Film was fully adhered with CAV-GRIP 3V Low-VOC Adhesive.
The winter conditions posed some challenges. “The weather played a very big role,” explained Ross. “We were faced with ice, snow, freezing rain, high winds, below-zero temperatures.” The majority of the project was completed in December 2019, with just a few details that were finalized in the spring. Once the project was complete, a 20-year, 55-mph wind speed Total System Warranty was issued, in addition to a Paver Overburden Warranty, ensuring that Mission Point Resort’s roofing system will keep their guests dry and protected for years to come.
“We had a roof that was struggling, and now we are able to take that and turn it into the real centerpiece of Mission Point,” said Mark Ware, CEO of Mission Point Resort.
Ross agrees. “It’s amazing to see what it looks like now, compared to before we started the project,” he says.
TEAM
Roofing Contractor: Doyle Inc. Roofing, Cheboygan and Petoskey, Michigan, doyleroofing.com
MATERIALS
Membranes: 80-mil VersiWeld TPO, 60-mil VersiWeld TPO with APEEL Protective Film,
115-mil VersiFleece TPO, Versico, versico.com
Architectural Pavers: Sunny Brook Pedestal Pavers, sunnybrookpressedconcrete.com
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