Permeable pavers make project possible

Permeables are the key to building a nearly flat driveway and the creation of a garage rooftop terrace.

Outdoor space comes at a premium in a neighborhood of South Minneapolis where large nicely kept houses were built close together on small lots in the early 1900s. One homeowner had an idea how they might get more outdoor space, but they weren't sure it could be done.

Their 2-story house sat on a hill some 4' higher than the back alley 70' away. The alley served as the main access to the neighborhood's backyard driveways and garages. What if they tore off their old 1-car attached garage and built a larger garage with a flat roof they could use as a terrace? After all, some of the neighbors had garage rooftop terraces.

But, in this case, the rooftop of a new garage built on the same spot as the old one would make a rooftop terrace clumsy to access. The terrace would be part way between floors of the house just as the garage floor would be. Digging out the backyard to lower the garage, looked like an ordeal. Plus, it might even make the garage floor lower than the concrete alley – not a good drainage plan.

Clients want focus on the big picture

The homeowners decided it was time to see what could be done with their property. So they called Landscape Designer Glenn Switzer who had designed and built their last patio.

Now, Glenn doesn't design or build garages. He would bring in an architect, a structural engineer and a builder for that. But, Glenn does spend a lot of time understanding outdoor spaces and how those spaces should transition to one another and to indoor spaces. The homeowners called him in first because they knew that he focused on the big picture and had the capacity to tastefully pull together a substantial project.

"I met with them several times, did several drawings and a lot of laser work. I pushed them along because I needed to get an architect there to get the basic drawing for the garage. There was a structural engineer involved because we peeled part of the brick off the house and opened up a load-bearing wall to replace a small window with a French door. So we had to get that worked out.

"I needed to get the builder there to finalize exactly what the garage was going to be, especially how far down the garage floor needed to be. That's when I could go out to get the real measurements I needed to determine what I needed to do with the landscape plan."

The verdict

The finalized garage floor elevation was 4' lower than that of the old garage, and only 1" higher than the concrete alley 45' away. Glenn says, "That sealed the deal for permeable pavers."

Though the drive was nearly flat, a permeable installation on this site would still eliminate nearly all runoff. Water flowing through the pavers and drainage-rock base would quickly percolate through the sandy soil to the aquifer.

"If it had been a different soil type that infiltrated more slowly, we would have looked at increasing the amount of sub-base aggregates to store more water. But I was extremely confident in the infiltration rate of the soil there. Knowing your soils is paramount when you work with permeables. We also knew there wouldn't be a water table issue. We could see the drop to the elevation of the creek at the end of the alley."

The homeowners liked the idea of permeable pavers reducing runoff to the creek (classified as an impaired waterway). Conversely, with the drive being nearly flat, Glenn was concerned about insufficient runoff (standing water) had they used a sealed pavement like asphalt. "I don't know how we could have graded it to have enough drop to prevent ice buildup in a Minnesota winter or water problems after a heavy rainfall."

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Managing construction

With the elevations and garage plans set, Glenn finalized the outdoor living area plan. By lowering the drive 4' at the garage entrance, they would need to remove upwards of 300 cu. yds. of soil and add several steps.

For excavation, the property was close to a dream site, all sand and gravel with no surprises. Glenn says the only real construction challenge was the limited staging area. The alley was in regular use by the neighbors so everything had to be staged in the small backyard.

"For the permeables I think we brought in 6 to 8 truckloads of drainage stone, and then 14 pallets of pavers. They needed to show up at the exact time that we needed them, and they did. Counting on suppliers to do that is all about building those relationships. It's also on the construction management and taking photos each day.

"We take 10 to 30 digital photos every day of every substantial piece of work completed. If I'm not on site I can look at the images and know exactly where a project is and schedule deliveries, sub-contractors and our crew accurately into the future."

This photo diary details how everything was constructed. It builds value with clients who can see just how involved a project was. It also serves as a record for Glenn showing where lines are buried, etc. if they need to do maintenance or build an addition.

Looking to the future

Focusing on the big picture and helping the homeowners get the most out of their property takes Switzer Nursery & Landscape beyond happy clients. It leads to more work in the future.

Conduit is in place to add outdoor lighting. They've discussed a pergola and an outdoor fireplace. For next year, the clients are looking to improve the front yard. Glenn says, "The backyard is more of a private space and neighbors don't stop by as much. I do a lot of front entry patios. I like to provide that front porch feel. Spaces in the front allow neighbors to interact and strangers to interact more easily."

Plus, the front of the house faces the west so it's going to be warmer, perfect for the fall and spring when it might be a little too cool in the backyard. Clients appreciate thoughtful planning focused on giving them what they really want. They'll invite Glenn back again, and recommend him to their friends.

The original garage was pretty much just tacked onto the house. It didn't have frost footings. Once torn down, the homeowners cleaned the brick for reuse on the house where brick had been removed during the new garage construction.

The colors in the wall are the result of using 6 varieties of stone. The steps are a Minnesota dolomite stone like the accent stone used on the house.

The edge of the landscape bed marks the lot line on the right. No room for much beyond the straight staircase. Upwards of 300 cu. yds of soil was removed.

Upwards of 300 cu. yds of soil was removed.

Borgert Products concrete Step Units work with the natural stone walls at about $100 less (each) than the stone steps on the other side.