Enhancing the Energy Efficiency of the Northern Great Lakes Visitor Center
Located just west of Ashland, Wisconsin, the David R. Obey Northern Great Lakes Visitor Center helps people connect with the historic, cultural and natural resources of the northern Great Lakes region by providing visitor information, experiential learning and community programs. The facility includes multiple exhibition spaces, community centers, an information center and gift shop, two theaters, and a five-story observation tower. It’s also home to the regional archive office of the Wisconsin Historical Society.
The flexibility of the NGLVC’s multi-purpose design makes it a marvel of space efficiency. In terms of energy efficiency, however, the Visitor Center needed immediate attention.
CHALLENGE: Preserving History, Wasting Energy
An initial blower door test indicated significant air leakage throughout the facility. Subsequent tests confirmed the problem, while a thorough inspection of the building’s attics and interstitial spaces revealed multiple opportunities to upgrade insulation.
For the KV Build Team, the principal challenge involved assessing the building’s needs respective to specific spaces – of which there were many. “In a facility this size, with multiple environments, varying ceiling heights, complicated air flows, and a lot of variation in the quality and degree of existing insulation, perhaps the biggest challenge was on the front end. We needed to get a precise understanding of the nature of the building’s issues and how best to address them,” said Eric Dymesich of KV Build.
SOLUTION: Protecting a Repository of Knowledge
“Our knowledge of building and insulation science, along with our understanding of how to optimize the efficiency of air and moisture barriers, really came into play at the NGLVC,” continues Dymesich. “But once we developed the plan, executing on it wasn’t markedly more difficult than any domestic project.”
Remediation of the NGLVC’s energy efficiency issues involved both insulation and air sealing and took KV Build’s 6-person team (with subcontractor assistance) about 5 weeks to complete. The principal areas of work included:
Thermal testing indicated an R-20 out of an R-38 fiberglass batt insulation. Moreover, most of the lounge’s can lights had no insulation of them, and all the HFAC louvres were uninsulated. KV Build installed can light covers throughout the space and applied 2” of closed cell spray foam over the entire ceiling, soffits and can light covers. Afterwards, R-50 cellulose was blown on top, bringing the total R-value to 64. The duct work was insulated with 3” of closed cell spray foam R-21.
In the center area of the main floor, cold air entered between the second floor and the drop ceiling. Here KV Build installed sheetrock and taped the walls between this space and the attic with 5/8” drywall, providing a firewall from the attic to the interstitial space between the floors and tower. This also provided a surface onto which the beam sprayed 8” of R-32 open cell foam followed by fire retardant. These actions stopped the cold air from pouring in from the attic sides and cooling the space between the first and second floor. KV Build also installed an access door and walkway to enable access from the attic.
The theater ceiling had been insulated with R-38 fiberglass batt insulation. Here can lights were exposed and heat louvres had no insulation on parts of them. In addition, the ceiling framing tied into the wall about 16” below the top plate, allowing for cold air to flow down the inside of the wall or heat to flow out of the wall to the roof deck – a potential cause of ice dams.
KV Build sealed up the gap between the wall and ceiling by spraying from the ceiling to the sheathing on the outside of the wall. Can light covers were installed aalong with vent shoots at the eaves, and the entire ceiling was air-sealed with 2” of closed cell foam. KV Build then reinstalled the fiberglass and blew R-46 cellulose on top. The duct work was insulated with R-21 closed cell foam.
In the tower ceiling, inadequate insulation warmed the attic to the same temperature as the public spaces blow – approximately 73°F – even as the outside temperature hovered around 28°F. Here, all fiberglass was removed and the duct work repaired. An access door was installed as well. Then 9” of spray foam insulation was applied to the attic-side of the ceiling, providing R-63. Next KV Build sprayed 2” on the duct work, bringing the total insulation to R-42. The cold air returns were insulated with 5” of foam for an R-35.
Elevator shaft walls were already insulated, but the team sprayed 6” of foam over them to bring the total insulation value to R-61. The steel beams for the elevator shaft were insulated with 2” of foam, R-14, from the elevator shaft to the roof to reduce conduction heat loss.
Like many of the other spaces, the entryway walls had R-19 batt insulation. Significant energy loss occurred here between the attic wall and the HVAC chase at both ends where it met the attic. Significant cold spots were also found in the fiberglass insulation walls. To remediate the issue, KV Build sprayed the walls with 8” of open cell foam R-32. The ceiling was air sealed and then ad R-46 cellulose was blown over the R-38 fiberglass batt insulation. This process eliminated the connection between the HVAC chase and attic sides. The team also evened out the wall insulation, making it consistent across the wall with just a slight temperature difference at the framing members due to the density of the different materials.
Significant thermal transfer also occurred in the gift shop ceiling, where exposed studs and numerous holes in the air barrier allowed substantial air flow through the fiberglass insulation. Here holes were patched and the entire ceiling was sprayed with 2” of closed cell foam. The walls were insulated with 8” of open cell foam to R-32. The ducks were insulated with 3” of closed cell foam R-21. Then a minimum of R-46 was blown over the 2” spray foam, bringing the total R-value to 60. KV Build also installed an access door into the space between the plumbing walls in the bathrooms.
The tower walls were poorly insulated with R-19 batt insulation, and the uninsulated steel beams were a large source for thermal transfer and condensation. There was a large gap at the top of the beam that allowed cold air to flow in between the inner sheet-rocked tower wall and the outside insulated wall. This was a major source of heat loss.
KV removed the fiberglass from the tower walls and installed 8” of open cell foam on the walls and over all the steel beams, eliminating thermal transfer and achieving an air seal of R-32. We also fully filled the gap above the beam with spray foam, sealing up the entire wall and stopping air flow into the space.
Main Upper Attic
The main upper attic suffered significant heat loss through each truss member and seam in the insulation. Convective looping took place in the fiberglass, reducing the total effective R-value of the fiberglass substantially. KV Build remediated the issue by air sealing the attic. Duct work was insulated with 3” of closed cell foam. At each partition wall walkways were built with spring closures and latches. An insulated access door was also built and installed. In addition, vent chutes were installed and venting was cut in. Then E-50 cellulose was blown over the R-38 fiberglass batts.
Second-Floor Mechanical Room
This space had R-38 fiberglass batt insulation and R-19 fiberglass insulation on the walls. No vent chutes existed, although there was a vented soffit. Here KV Build removed the old insulation and installed vent shoots in the sloped roof down to the soffit. Two inches of closed cell foam was sprayed on all the flats and 3” on the duct work. The attic walls were insulated with 8” of open cell foam R-32 and then cellulose insulation was blown, bringing the flat ceiling R-value to 50. An access door was built and insulated to R-60, with a gasket around the door to stop air leakage. Venting was also cut into the roof to allow for additional venting needed in the space.
Throughout the facility, duct work or its insulation was in poor condition. We repaired all duct work as needed and secured the existing insulation before applying 3” of closed cell foam R-21.
RESULT: Securing the Future for a History Center
Thermal imaging and blower door tests showed the overall effect of the air sealing of the building. That report indicated a 30% reduction in air leakage, without taking into account the thermal savings through added R-Values in the attics. At the beginning of the project, most attics had an estimated effective R-Value of 20-30. At the project’s conclusion, all attics had a minimal of R-60 with thermal transfer almost eliminated. Attic walls had been insulated with R-19 batt insulation, which performs very poorly under the conditions to which the building was routinely subjected. That was replaced with 8” R-32 spray foam, applied over the studs. This stopped thermal transfer through the stud members by completely covering them.
Estimated annual savings for the Northern Great Lakes Visitor Center are in the hundreds of thousands of dollars. Moreover, our work can be expected to yield significant ROI for many years to come. We’re proud to improve the operating efficiency of the NGLVC, and in so doing enable it to use a larger share of its budget to preserve the state’s cultural and historical assets.
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