Rectangular pool with pale concrete deck, looking back to the house through tall trees

Scarborough, 2018–2020

Ravine’s Edge

A pool on sandy, sloping, conservation-authority land with three feet of side access. Geotechnical assessment, shoring, an engineered wall.

The problem

Some back yards are hard. This one had everything against it: a slope down toward the ravine, soil that was mostly sand, and land regulated by the Toronto and Region Conservation Authority.

The decision

So nothing was left to chance. A full geotechnical investigation and slope assessment came first: the engineers drilled a test borehole about 22 feet (6.6 m) deep with a compact rig, tested the soil and modelled how the slope would behave. From that came engineered shoring, an engineered retaining wall and a pool designed around what the ground could hold. We managed the approvals as the homeowners’ agent: the conservation authority, the City’s ravine protection permit, urban forestry and an arborist’s tree plan.

At a glance

Location: Scarborough
Built: Sept 2019 – Oct 2020
Site: TRCA-regulated slope toward a ravine; very sandy soil
Engineering: Geotechnical investigation and slope stability assessment (Landtek), engineered shoring and engineered Permacon retaining wall (Mantecon)
Approvals: TRCA permit, City of Toronto ravine protection permit, urban forestry tree permit, arborist reports; NLG as permit agent
Access: Three feet down the side of the house, inside tree-protection hoarding; compact machines and a conveyor
Guide: Building on a slope
Services: Design-build, Pools, Permits and engineering, Pavilions and structures

Before and after

Fern-covered slope at the back of the yard — From the house: the fern slope is now the pool.

Pool and sunken lounge on the same slope, seen from the house — From the house: the fern slope is now the pool.

Back of the house with lawn, trees and Adirondack chairs — From the slope, looking back.

Pool, lounge and planting with the house behind — From the slope, looking back.

Back corner of the yard with trampoline and ferns — The back corner by the trees.

Gravel fire-pit area with the pool and cabana beyond — The back corner by the trees.

The build

Then we had to get in. The only way to the back yard was a three-foot gap down the side of the house, narrowed further by tree-protection hoarding. We brought in specialised compact machines and moved the soil out by conveyor.

Mini excavator squeezed between the house and the fence — Three feet of access.

Conveyor truck moving soil out from the back yard — Soil out by conveyor.

Plywood shoring holding back sandy soil — Building the engineered shoring wall in the sand.

Pool shell covered and dusted with snow — The pool shell, December 2019.

Permacon retaining wall blocks being laid — The engineered wall going up.

Fire-pit corner looking over the lawn to the pool and cabana — Fire-pit corner.

Round daybeds beside the pool and cedar cabana — Daybeds by the cabana.

The result

What’s there now is a complete poolscape: the pool, concrete decking and a Permacon wall holding the slope, set into a garden that looks like it was always meant to be there.

Design:: Natural Landscape Group
Geotechnical:: Landtek
Engineering:: Mantecon