A downtown street with a distinctly 19th-century feel could soon get a major vertical addition.

Plans have been filed to redevelop a block containing a handful of heritage buildings at the intersection of Toronto Street and Adelaide Street East, including the current home of popular Italian restaurant Terroni Adelaide.

Architecture and planning firm SvN has applied on behalf of an applicant — believed to be Goband Development, which purchased the site in 2019 for $65 million — to bring a new 80-storey skyscraper to the site while attempting to retain the heritage character that makes this block so unique.

The project team has proposed a massive new addition to the skyline which would rise to a height of almost 259 metres. If completed today, the tower would stand as Toronto's sixth tallest, just over one metre taller than the existing One Bloor East.

A primarily residential complex is planned with 2,618 square metres of office space and 1,599 square metres of commercial retail space in its base, anchoring the over 800 homes across more than 61,000 square metres of floor area planned for the tower and mid-rise components above.

Despite the lofty height ambitions, SvN states that the project would "sensitively integrate heritage buildings and reactivate a connection to Courthouse Square," through coordinated efforts with heritage specialists E.R.A. Architects.

Among the properties on-site is the York County Courthouse at 57 Adelaide East, a building dating from 1852-1853 that holds a dark history of capital punishment, but is currently best known for its pizzas and Italian fare. The plan includes a full retention of the courthouse building, which likely means no big move on the horizon for Terroni.

Other buildings included in the redevelopment are Consumer's Gas building at 17-19 Toronto Street, built in 1899 and 1876, which would have external and internal heritage elements restored, while a new-build mid-rise would be added above.

The property at 25 Toronto Street, currently home to another Italian eatery, Mirto, would only have its facades retained, meaning the existing business would be forced to relocate if the project gains approval.

The only property planned for full teardown on the site is 23 Toronto Street, a single-storey building with no obvious heritage attributes.

This structure would be replaced by what architects describe as a "distinct and understated glass volume that sympathetically matches the height of the existing three-storey heritage buildings to its north and south," serving as the main entrance to the residential tower above.

Architects behind the project say that "as the slender new tower rises to its full height, frit and transparent detailing create a deft pattern of softly-rounded balconies while the tower's massing will be further broken down into patterned segments."

Such features are evident in renderings, though are best expressed in a dusk-lit rendering of the modern massing juxtaposed against the heritage base.

A total of 816 residential units are proposed for the relatively compact site, broken down into a mix of 80 studios, 462 one-bedrooms, 219 two-bedrooms, and 55 three-bedroom units.

A whopping 67 per cent of the units feature either a single bedroom or no dedicated bedroom space, which would limit the project's accessibility to families, and may prove to be an even bigger issue than the height in gaining approval.

In terms of parking, the proposal joins a trend of plans with minimal vehicular accommodations, with just 51 spaces serving the entire project. Nearby TTC access and a massive bicycle parking component of over 930 spaces would be expected to serve the majority of residents' local transport needs.