Vegetative system to repair three buildings, improve lakefront view recommended by Public Works Board
Port Washington may soon have its own version of Al Johnson’s green roof in Sister Bay — this on the lakefront.
The Board of Public Works on Tuesday voted to install a green roof on three of the buildings that make up the wastewater treatment plant.
It’s a measure that members said would improve the lakefront view from Upper Lake Park while making a needed repair.
The move will complement improvements to the walkway to the north beach that the city will make this spring, board members noted.
“Given the location, I like the idea of it,” Ald. Mike Ehrlich, a member of the board, said. “It’s instant gratification. We’re talking about a significant visual impact.
“And we’re already improving that area by improving the entrance to the beach.”
Public Works Director Rob Vanden Noven said the concept of a green roof is something that’s been talked about for years.
“The ball really got rolling because more and more comments are being made about how unfortunate it is that the plant is right on the lake,” he said. “We’re trying to blend the plant in as much as we can.
“But as nice as the sedum roof is going to look, the two sludge storage tanks aren’t going to let people forget what’s there.”
The three roofs that will have vegetative systems installed are the administrative and headworks buildings — the tallest on the site — and the UV building on the southeast end of the property. These are the buildings most visible from the park, members noted.
The move for a green roof is also economic, board members noted.
While it is a more expensive roofing option, the vegetative system is expected to increase the life of the roof by as much as 20 years, they said. It will also act as insulation and cut heating and cooling costs for the buildings.
That savings alone could amount to $5,000 annually, Wastewater Supr. Dan Buehler said.
The green roofing system that will be used incorporates pregrown mats of sedum, a fairly hardy plant that can tolerate drought and doesn’t need a deep bed of soil, said Erik Krumholz, a consultant with Tremco Roofing.
“You’ll have kind of an instant, ‘Here it is’ effect,” he said, because the sedum is grown before the mats are installed.
A root barrier is installed atop the roof system, then a drainage layer is added before the sedum mats are put into place, he said. Only four inches of soil is used in the system.
An 18-inch walk system will be installed around the edges of the roofs.
The system will hold one gallon of water per square foot during storms, eliminating that runoff, Krumholz said.
Krumholz noted that a leak detection system is included in the roof, allowing any repairs to be made without disturbing much of the roof.
There is a 20-year warranty on the roof and a three year warranty on the plants, he added.
Krumholz said green roofing systems have been around for decades but are becoming more popular, noting they have been installed at the Milwaukee Public Library and the Milwaukee Public Museum.
The library’s 25,000-square-foot roof cost $900,000, or $36 per square foot, he said, and the museum’s 4,200-square-foot roof cost $256,000, or $60.95 per square foot.
The estimated $170,000 cost of the three roofs in Port, which total 6,470 square feet, is about $26.26 per square foot, he said.
The board recommended hiring Cudahy Roofing to do the work — which includes traditional roofing systems on the majority of the buildings at the plant as well as the three green roofs — at a cost of $482,000.
Of that amount, $185,000 is for the green roof.
A railing system will also be installed on the roofs. which will add about $40,000 to the contract.
The Common Council is expected to act on the recommendation when it meets Wednesday, Feb. 18.