Sweeping View: The 77-foot-long vanishing-edge pool forms a sweeping arc connecting the main house with the guest house, seen in the top image. A black pebble finish adds to the reflective quality and adds a modern touch, while the Tennessee fieldstone deck ties with the home’s rustic materials.
Dorsey wanted to make the pool look as full as possible, with very little freeboard — that dry space on the wall between the water’s surface and coping. To achieve this, he had a coping custom-made. Measuring only 1 inch deep where it sits over the bond beam, it is approximately 2-1/2 inches thick where it hangs over the water. This helps visually close the gap between coping and water.
The design team chose to cap the vanishing edge weir with a fossilized marble from Morocco. The warm tones and embedded fossils echo the modern and rustic feel of the house; however, the material is not the most durable for enduring freeze/thaw conditions. For this reason, the team obtained extra stone with the intent of replacing pieces down the line. The material also veneers the raised perimeter sun shelf (not shown).
Eye for symmetry: Flanking the point where water enters the pool from the stream are two square, perimeter-overflow vessels. On the right sits a spa. For symmetry’s sake, Dorsey mirrored the spa with a perimeter-overflow sun shelf on the opposite side of the stairs. Having the vessels spill over on all sides and sit only 6 inches above water level made the pool seem more full.
Point of connection: Dorsey designed an Ipe bridge to circulate traffic from one deck to another and connect the stream with the pool. He didn’t want handrails on the bridge to obstruct the view so, instead, he created an edge using the same stone that veneered the dwelling structures. The bridge also helps create the illusion that the stream flows into the pool. Underneath the bridge is a wall separating the two vessels. At that point, water from the stream is pumped back up to the originating pool. On the other side, inlets supply water to create the small drop into the pool.
Piecing a natural puzzle: The homeowners asked for a stream and rock waterfeature with a wide fall. A 300-foot stream comes from the upper property down near the pool before spilling over into the final basin. The bottom fall required the right kind of stone. “To make this wide waterfall appear natural, that rock had to look like it had always been there,” Dorsey says. “It had to look like bedrock — a large rock with horizontal grain. “If the grain of a rock in nature is tilted up, you won’t have a wide waterfall. It’ll be coming off the side, in a narrow little gush of water.” There are two kinds of waterfalls in nature, he explains — the type involving large stones like his customer wanted, and others with smaller colluvial rocks that are more jumbled, less structured. “Colluvial waterfalls are generally not very high, and they exhibit concentrated flows,” he says. “Bedrock situations are the only time you get the Niagara Falls look, the Yosemite Falls.”
Building the waterfall: The original contractor on the stream had planned to use a rubber liner, but Dorsey wanted to minimize chances of leakage and failure. Considering the property was on a hillside and the backyard shored up with a 16-foot-high retaining wall, damage and costs to repair could be catastrophic. “They’d just spent about $250,000 on a retaining wall just to create a site for the pool,” Dorsey says. “So we can’t have a failure. Also, we needed something to support the weight of some large stones.” For durability, he and his crews built a 19-foot-long concrete shell to capture water from the final drop. The basin’s back wall is buried about 8 feet deep.
To assemble the waterfall, Dorsey created a rendering mapping out the placement of key specimens. Boulders were extracted from a remote mountainside location, then sent to a granite fabricating facility, where a 10-foot diameter saw was used to cut the rocks to fit against the basin walls. To fit one 13-foot specimen in a corner, for instance, fabricators cut 3 feet off one end and sliced the back. Explains Dorsey: “That was by far the most challenging part of this project — standing in the rain with a printout of my 3-D concept, looking at 15 or so very large boulders laid out on two tractor trailers, trying to decide where to mark the cuts needed to make it all come together.”
A flat stone chosen to create a wide fall. Some of these larger specimens were cut to fit against the walls of the concrete basin.
Oftentimes, outdoor kitchens are integrated into the poolscape, so the chef can easily chat with others in the backyard. In this case, however, Dorsey wanted the opposite. The wealthy homeowners generally don’t do their own cooking, but have a staff that prepares meals for them. “So it becomes more like a commercial application, where you have, say, a swim-up bar at a resort,” Dorsey explains. The kitchen features a sunken floor, allowing guests to see over the bartender and enjoy the hillside view.
When you build a vanishing-edge wall that long, your main concern is its structural integrity. It’s not about the weight of the water, it’s about the expansion and contraction of the concrete. It becomes more like a dam. It’s the same consideration that an engineer goes through when he’s designing any large concrete structure. Thermal expansion becomes one of your major design parameters. So there is a lot of steel – no. 5 bars at 4- or 6 inches on center.