Exterior detailing lends permanence to new downtown building

By Ron Smith, MRAIC

Following a global trend of downtown work and living lifestyles, the Halifax Regional Municipality has had substantial growth within its downtown areas. The Keep project was developed along one of the busier streets leading into the urban core. The project includes two levels of parking, main level commercial uses along three street frontages, and 72 residential condominium units.

The project is located on the Halifax Peninsula within an active commercial and residential neighbourhood and within walking distance of major universities. It replaced an aging low-rise structure containing retail and business services.

Ideally located, development of this property was challenging to meet both planning and construction limitations. The building mass steps down from Quinpool Road, along a busy commercial street towards a low-rise residential neighbourhood. The building footprint creates a south-facing internal courtyard.

The client had first requested a brick and stone exterior but wanted the speed and long-term sustainability of pre- cast concrete. Additionally, the limited construction space along three streets and restrictive limits to work within adjacent properties, pointed to a precast concrete solution for a quick erection of wall panels for both street frontages and to inner courtyard building elevations.

A remaining issue for the client was the restrictive colour and textures usually seen on other precast concrete projects. Studioworks researched both embedded brick and face panel form options with the help of Strescon, a local precast concrete provider. The building expression developed into an urban stone and clay brick finish that the building owners were seeking.

Thin-set brick and precast concrete finishes

Strescon Limited supplied and installed 241 architectural precast concrete wall panels in two finishes. The first six floors were clad with a precast concrete panel embedded with thinset red brick and precast concrete banding around the window and door openings.

The upper two floors were clad with a precast concrete panel with a 300 millimetre x 600 millimetre (1 foot x 2 foot) limestone pattern created using a formliner to achieve the stone look. The visual effect is one of permanence, as though the building has been standing for many years.

The upper two storeys and mechanical penthouse were planned in a large light colour stone face pattern visibly lowering the building height. Window trims and sill details gave additional scale.

Precast concrete panels were used for the majority of the building cladding and easily coordinated with the poured-in- place concrete structure. The panel back face was insulated with high-density spray foam, and wall detailing generally followed the CPCI Architectural Precast Concrete Walls: Best Practice Guide.

While most of the panels were placed in a typical fashion, building setbacks determined by city planning and the resulting termination of precast concrete panel bottoms above finished roof membranes required a different sealing method. The panel bottoms and lower inner wall assemblies above roof terminations were sealed with a two-part waterproof sealant hidden behind the panels, leaving the face of the panels untouched.

The building has been well received by the general public, quickly leased and condominium units sold, proving good design and construction has long-term value.

Ron Smith, MRAIC is the Principal at Studioworks International Inc. in Halifax.