At this residence on Shubenacadie Grand Lake in Nova Scotia, the demise of a hand-built rock wall by high water levels and strong winds over a long period of time led the homeowners to search for a better alternative. George Searle of Searle Environmental Services Limited engineered a gravity structure comprised of 350 Redi-Rock retaining wall blocks that rely on their sheer mass to retain the ground and protect the property from encroaching water. Faced with a ledgestone texture, each one was 41"-deep, in a variety of heights and widths, but all weighing over a ton. The footing for the wall was a leveling pad of crushed rock followed by a base course. Photo: Duracast

The Challenge
It's hard to imagine dealing with waves lapping at a home's door, but in 2012, that's exactly the situation this Nova Scotia family found themselves in.

"As teenagers, my husband and I dated here on the old rock wall. It used to be a camp," explained homeowner Heather Fisher. "We always said we'd like to own this property someday. Long story short, we bought the property and the wall always held back the water. But then a few years ago, the wall came down in a storm and the water came right up to our doorstep. We had to use sand bags and everything to try to keep the water out."

The house is located on an exposed point on the shore of Shubenacadie Grand Lake. "It's a large inland lake by Nova Scotia standards," explained George Searle of Searle Environmental Services Limited. "They had what I would call the 'perfect storm' - extreme high water levels and strong winds for a long period of time. This destroyed the hand-built rock wall that had been in place there for years, and it also eroded the shoreline. The waves were breaking all the way up to the front door threshold."

The Solution
When the Fishers initially consulted with Searle, they wanted another natural stone wall installed. "He recommended that we not go that route though. We're out on a peninsula and when we get a Nor'easter, it really hits the shore hard."

Searle recommended a precast block retaining wall as a solution. "Our firm had great results at another shorefront property on the same lake a few years previous, so we had no hesitation in designing a protection system for them."

Searle designed the wall as a gravity structure, which relies on the sheer mass of the one-ton blocks to retain the soil.

"We selected Redi-Rock for the weight and ballast they have. It is more than sufficient to deal with the wave energy here," said Searle. "There are a lot of worse cases in coastal situations in Nova Scotia, but it's amazing the shoreline damage that can occur when you get a perfect storm on an inland lake like this."

The manufactured product is a precast segmental retaining wall system, which allowed Searle to design the wall to follow the natural shoreline. "We were able to do this because of the way the system interlocks. It gives you flexibility to incorporate the natural curvature of the shore," Searle said.

To install the new wall, the crew from Kel-Greg Enterprises Ltd. removed the old stonewall, installed the new wall further back on the property, then used the original stones as toe protection in front of the face of the new wall.

"There's some wave action against the base of the wall that could cause toe scouring, and we wanted to prevent that," Searle said. The crew was able to install the entire project from the shore during the low flow period (June-September) without staging any material or equipment below the ordinary high water mark.

Sitework and excavation company Kel-Greg Enterprises of Elmsdale, Nova Scotia set approximately 2,000 square feet of blocks with the help of two excavators and a skid steer loader. Because of the way the precast segmental retaining wall system interlocks, the installers were able to follow the curvature of the shoreline. The stones from the original wall, which had to be removed, were placed in front of the face of the new wall to help prevent toe scouring. Photo: Duracast




The blocks come in a variety of face molds, each with 5.75 square feet of face area. The manufacturer states that they can be installed in such a way as to have up to 115 square feet of non-repeating patterns. Photo: Matilyn Ozment/Redi-Rock Interenational




To provide access to the water, a smaller retaining wall with steps on one side of the house was built. The steps are the same product as the caps, of which there were 72, all weighing 665 pounds, which the manufacturer compares to the weight of two Sumo wrestlers. Photo: Matilyn Ozment/Redi-Rock Interenational

The Outcome
The project included 350 retaining wall blocks equaling approximately 2,000 square feet (185.8 square meters), plus 72 caps. The new wall stands about one foot (.3 meters) taller than the previous wall to give the home a little more protection.

"We've had the wall for two to three years now, and it's held up really well," Fisher said. "The ice just crashes against it in the spring when it's thawing, and the blocks all still look great."

In addition to shoreline protection, this project also included a boat launch incorporated with the wall. "It's the only one I've seen like it on the lake," Searle said. "That made it a bit unique."

The Fishers were so happy with the results of the wall that they've since expanded it. This project was the recipient in 2013 of the "Residential Wall of the Year" in the Rocky Awards, an annual honor recognizing the best projects from around the world completed with the manufacturer's products.