Building on a steep grade can give a home a grand appearance, but can also limit the usable landscaping space outside the house.
When the Sifton family decided to build a new home outside London, Ontario, they were faced with a challenge – creating an inviting, usable outdoor living space in their steeply sloping backyard.
As president of the homebuilding and neighborhood development company Sifton Properties, Richard Sifton is no stranger to the construction industry. For this project, the family wanted to install an in-ground pool, cabana, and gardens that felt like an extension of the house. The challenge? The total grade change from the bottom of the lot to the house was 19.23 feet.
To help the house and pool feel like they were part of the same context, the pool, cabana, and house needed to be terraced. Wall experts from Brown’s Concrete Products Limited and Peto MacCallum Ltd. Consulting Engineers designed the structural walls to support the landscape installation. Stone in Style Landscaping Limited assisted with the transportation and installation challenges presented by the site, and Darcy DeCaluwe, Stone In Style’s owner, directed the installation of
Installation took about two weeks, and required 2,200 square feet of Rosetta Hardscapes’ Outcropping Collection retaining wall precast blocks. Thirty-five Rosetta Dimensional Steps were also installed to create a path between the tiers.
Access to the home site presented some unique challenges for the construction of the project. The only way to reach the residence was by crossing a 4.5-ton capacity bridge, and transporting construction materials to the property required crossing over high-speed rail tracks during a very short window of time each week. Also, the driveway was ¾ of a mile long with no turn around, steep slopes, and limited width; these conditions restricted the size of trucks used and required drivers to back down at least one way.
To move the blocks and backfill onto and around the site, the crew was restricted to using a skid steer, as it was the only piece of machinery small enough to cross the access bridge with the product and still have the load capacity to carry the stone. The team used Rosetta Hardscapes’ Outcropping stone, a precast wall system that creates structural walls with the look, colors and textures of weathered natural stone.
“We were looking for a wall building material that would allow us to hold back the grade, and would deal with the significant loads that the slope would put on the wall. The goal was to create a structure that was attractive and visually interesting,” landscape designer Ron Koudys said.
In total, the walls required 2,200 square feet of Rosetta blocks in the Rideau Blend color scheme.
A 4.5-ton capacity bridge limited access to the area, so a S250 Bobcat skid steer was used to transport the materials onto and around on site. Getting the materials to the property also required crossing over high-speed rail tracks and backing up a narrow driveway.
Because of these constraints, the engineers tried to use as much native soil as possible to avoid excavating soil, trucking it out, and then trucking in fill. The native soil had very high clay content, making the design of the walls even more challenging.
During construction, Stone In Style’s crew exhausted the available on-site materials, and subsequently brought in pea gravel for the drainage column behind the wall blocks, and at times blended granular materials in with the native soil to make it more workable.
The walls range in height from 6.36 feet for the lowest wall, 5.87 feet for the middle wall and 2.95 feet for the uppermost wall. The house sat on the highest tier, the garden was built between the top and middle walls, and the pool was installed between the middle and bottom walls.
After preparing and laying a base course for the retaining walls, three tiers of curving walls were installed to create level ground for the pool and a garden area, and a stepped walkway was added to lead from one tier to the next. The walls were reinforced with Paraweb straps, as well as a geogrid, due to the significant load bearing capacity each wall required.
The walls range in height from 2.95 feet for the uppermost wall, to 5.87 feet for the middle wall, to 6.36 feet for the lowest wall. The house sat atop the uppermost wall, the garden was located between the top and middle walls, and the pool was built between the middle and bottom walls.
“The site conditions and limited access made the installation challenging,” DeCaluwe said. “It’s quite impressive to see the finished look though.”