Overview
On Sherbourne Street near Dale Avenue in downtown Toronto, a gutted heritage house was being converted into accessible senior housing by the Toronto Community Housing Corporation (TCHC), Canada’s largest social housing provider, with Axia Design Associates as the architect.
iScano was brought in during pre-construction to capture the existing conditions of the building and turn them into as-built documentation the architects, the construction crews and city reviewers could all work from. The original drawings could not be relied on for a structure this old and this altered, so everything the retrofit depended on had to be measured.
Input
- Access to a gutted heritage house, interior and exterior, before design work started
- Original drawings that no longer matched the building
- A design brief that had to fit new senior housing units inside the existing footprint
- New MEP systems that needed to be routed through the existing structure
Output
- Registered point cloud of the interior, exterior and adjacent site context
- Scan-to-BIM Revit model of the existing conditions
- Floor plans, internal elevations, sections and reflected ceiling plans
- 2D CAD drawings for planning and construction
- Navisworks-ready model for clash detection against the new design
Project stages
- Scope and control: agree the capture area with Axia Design Associates and TCHC, including the neighbouring buildings and site features needed for by-law reviews
- Terrestrial laser scanning of every interior space and the full exterior of the house
- Registration and QA of the point cloud into one coordinate system
- Scan-to-BIM: Revit model of the existing structure, from foundations to internal elevations and hidden architectural features
- Drawing set: floor plans, sections, internal elevations, reflected ceiling plans and 2D CAD
- Clash detection support: the model was used in Navisworks to check new MEP routes against the existing structure
Challenge 1: no drawings you could build from
The house had been altered over decades and then stripped back to structure. What drawings existed did not describe the building as it stood, and the architects needed to know the real geometry before they could lay out the new units.
Solution
We scanned the whole building inside and out and modelled it in Revit as it actually was, including the foundations, internal elevations and the irregular details a heritage house hides. Axia Design Associates worked directly on top of that model.
Challenge 2: fitting new mechanical, electrical and plumbing into an old structure
A retrofit lives or dies on whether the new services fit around the existing walls, floors and framing. Finding those conflicts on site is expensive.
Solution
The Revit model was set up for clash detection in Navisworks, so the design team could test new MEP routes against the measured structure and resolve conflicts before construction started.
Challenge 3: many stakeholders, one building
TCHC, the architect, the construction crews and City of Toronto reviewers all needed the same picture of the building, including how it sat against its neighbours for by-law compliance.
Solution
We modelled the adjacent buildings and key site features alongside the house so the one dataset answered planning questions as well as design questions. Every party worked from the same model and drawing set.
Outcome
- One reliable as-built dataset shared by the owner, the architect, the contractors and the city
- Rework reduced by an estimated 15–20% by resolving conflicts in the model instead of on site
- Design work proceeded without the usual back-and-forth over existing conditions
- Faster regulatory review thanks to the modelled site context
- Senior housing delivered on a site that would otherwise have needed extensive field verification
Need as-built documentation for a retrofit in Toronto? See our Scan-to-BIM services or 3D laser scanning in Toronto.
