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Private Residence

A unique floating stair with character and a story

Private Residence—Floating Stair

Toronto, ON

Architect: Architects Alliance

Client: Clemmensen & Associates Ltd.
Collaboration: Webb Yates Engineers

Completion: 2019
Category: Residential

Project Type: Stone and Structural Engineering
Stone Type: Charcoal Basalt Stone


2020—NSI Pinnacle Award of Excellence
(Residential-Single Family)


June 2020—The House in the Ravine


Jul 2020—Stone is Structure

Jan 2021—Masonry: Let’s Get Creative

This renovation project by Clemmensen Builders and Peter Clewes of Architects Alliance perfectly combines a contemporary vision with a historic multilevel dwelling set in a ravine in the heart of Toronto. With charcoal basalt stone flooring, a white interior pallet, and soft tone wood floors dominating all levels, punched windows were reconstructed with floor to ceiling glazing inviting ravine and city views on the main level. 


With such beauty, no one element of design could stand out amongst the others however; the solid Basalt stone feature stair seems to do exactly that. With an initial design to cantilever treads off of the supporting masonry wall, PICCO Engineering was brought on board to bring our stone and structural engineering expertise and experience to strategize and present a bolder approach. Our true span, post-tensioned, and solid stone “floating” solution was proposed and enthusiastically accepted. In collaboration with Webb Yates (London, England), full execution including material supply, engineering, installation, and quality control was provided. A true one of a kind stair worthy of this storied home and its peaceful setting.

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