The famous grass on the roof of Al Johnson’s is coming off – temporarily.
After 38 years, the roof has sprung a few leaks and needs replacing, but as co-owner Rolf Johnson discovered, this isn’t your normal roofing job.
“We shopped around quite a bit,” Johnson said. “A lot of people specialize in green roofs, but not many specialize in sod or grass.”
Eventually Johnson found a couple of Norwegians who were familiar with the original roof. They gave him some ideas for the job, and then Johnson came across FJA Christiansen Roofing, a Milwaukee roofing company, on the Internet. Christiansen President Todd Orvedahl said his company has been working with Rolf and his brother Lars Johnson for over two years to come up with the right plan for the project.
“Lars and Rolf really wanted to retain the original look of the roof and didn’t want to go overboard,” Orvedahl said. “This is a simple roof that had lasted a long time, so it has obviously performed pretty well.”
The existing roof was installed in 1973 and has a plywood base covered with felt paper and a plastic sheath. About six inches of soil and sod top it off, providing grazing for the goats that call the roof home through the summer.
Today’s grass roofs have as many as 12 layers of material, but the Johnson’s are keeping it fairly simple.
“It’s a little more complex than the roof we have now, but not too much,” Johnson said.
Orvedahl said a new membrane and soil retention layer are the only parts that will be significantly different from the original roof, but those changes won’t be apparent from the outside. Atop the plywood will be a Sarnafil thermoplastic membrane for waterproofing, followed by a drainage mat with filter for the soil retention system, followed by sod. The roof will also integrate an irrigation system, cutting out the need for dragging hoses and sprinklers around the roof to water it.
“But we have to be careful with what we put up there,” Orvedahl cautioned, “because those goats like to eat anything.”
The soil retention system is crucial; something the Johnsons learned from experience shortly after the original sod was laid. When Rolf Johnson was in elementary school, the entire sod layer slid off the roof.
“They told us not to over-water it too early in the season,” Johnson said, “but my dad was afraid the grass was going to die, so he watered it a ton. Sure enough, the sod slid right off.”
Johnson said the old roof has served them well, but it has sprung a few leaks, and he has a good idea where those came from.
“Back in the late 1970s or early 1980s, as a joke, a bunch of high school kids covered the roof in a hundred yard signs, pretty much every kind of sign you can stake into the ground,” Johnson recalled. “Even we thought it was pretty funny when we saw it, but I think some of those may have pierced the membrane and eventually those holes turned into leaks.”
The restaurant will stay open throughout the roof work, which Johnson hopes is done by May 15, though they may have to close for a day or two in that stretch to replace the dining room carpet. The goats, however, may not be grazing on the roof again for until June. Depending on the weather, it could take two to six weeks for the sod to take root enough to handle heavy goat traffic.
Christiansen is a subsidiary of Tecta America Corporation, the largest green roof installer in the country. Orvedahl said Christiansen does more green roofs than any other company in Wisconsin, including the largest in the state – a 60,000 square foot roof for the Rockwell Automation headquarters, right below the famous Allen-Bradley clock tower in Milwaukee.
Orvedahl said many of his employees are familiar with the restaurant through visits to Door County as kids or with their own families.
“Our entire organization is very excited to work on this project and proud to be affiliated with Al Johnson’s,” he said. “It’s not the first grass roof we’ve worked on, but it is the first with goats on it.”