Outbuildings
A Kentucky Garden Shed With a Planted Roof
Sedums help prevent runoff and add a green touch to this charming backyard building
At first this family wasn’t thinking green when they wanted storage for their garden tools, pots and lawn mower. But the adjacent property’s standing-water problem gave builder Sam Graham an idea — planting the roof to catch the rain rather than having it run off and potentially make the problem worse. “It added a few thousand dollars to the budget, but my client and their three young kids really loved the idea,” he says.
Graham used EPDM (ethylene propylene diene terpolymer), a synthetic rubber roofing membrane, under the substrate. Although there are gutters on the shed, they are really only necessary during a very heavy rainstorm. Otherwise, the green roof absorbs most of the water.
This closeup shows us how far apart the sedums were planted. Sedums thrive atop the roof, and in Kentucky, they don’t require additional watering. However, water played a big role in the structural calculations. When engineering the structure, Graham had to not only calculate the weight of the roof, substrate and plants, but also figure in how much weight rain or snow could add. The estimated saturated weight of the green roof was about 2,500 pounds, so Graham designed the farming to support double that amount, just to be on the safe side.
The 3 inches of substrate is composed of a mix of lava rocks, soil and sand. Using lava rocks for the base layer helped keep the roof as light as possible. He designed this mix with sedums in mind because they like dry soils.
The 3 inches of substrate is composed of a mix of lava rocks, soil and sand. Using lava rocks for the base layer helped keep the roof as light as possible. He designed this mix with sedums in mind because they like dry soils.
The shed does not have electricity and is mostly used for storage. A exterior shelf for potting plants extends its usefulness out into the garden.
The style of the shed has Arts and Crafts and Craftsman roots, as those styles are seen around the neighborhood. “The general design idea for the shed was ‘sophisticated barn,’” Graham says. Other clients of his gave him these antique leaded glass windows, which were removed from their circa 1900 house during the remodel. Repurposing them on this project helped the shed fit in with this home, which is about the same age.
The bracket details were inspired by the surrounding architecture. “Most of the homes in the neighborhood were built from around 1900 to 1920,” Graham says. “The brackets add a little Victorian flair.”
The style of the shed has Arts and Crafts and Craftsman roots, as those styles are seen around the neighborhood. “The general design idea for the shed was ‘sophisticated barn,’” Graham says. Other clients of his gave him these antique leaded glass windows, which were removed from their circa 1900 house during the remodel. Repurposing them on this project helped the shed fit in with this home, which is about the same age.
The bracket details were inspired by the surrounding architecture. “Most of the homes in the neighborhood were built from around 1900 to 1920,” Graham says. “The brackets add a little Victorian flair.”
For the inner framing, Graham used 4-by-4 treated lumber that sits on poured concrete piers set at frost depth. This depth will vary depending on where you live, so be sure to check local building codes.
He scored the budget-friendly poplar siding from a local man who fells and mills the trees growing on his farm. The poplar planks are 1½ inches thick.
He scored the budget-friendly poplar siding from a local man who fells and mills the trees growing on his farm. The poplar planks are 1½ inches thick.
Sliding barn doors add to the building’s charm. Graham made the hardware himself.
More: How to Add a Backyard Shed for Storage or Living
More: How to Add a Backyard Shed for Storage or Living
What happens here: Storing and organizing garden tools, pots, soil, mulch and plants; potting plants
Location: Louisville, Kentucky
Size: 120 square feet (11.1 square meters)
Designer-builder: Sam Graham of Graham Design and Construction
As you can see in this photo taken one year after installation, the sedums spread beautifully to completely cover the roof. “They turn a nice red color in the fall,” Graham says.