Moriyama Teshima Architects have completed the new headquarters and multi-tenant complex for the Ontario Secondary School Teachers’ Federation (OSSTF/FEESO). The 127,000-square-foot, three-storey building demonstrates how mass timber can support both environmental performance and workplace wellbeing.

Mass Timber Construction

The project uses cross-laminated timber (CLT) floor slabs and glue-laminated timber (GLT) beams and columns. Where possible, the architects sourced the structural elements from Canadian suppliers, supporting the regional timber industry. By choosing mass timber, the design team cut the building’s embodied carbon while also creating warm, natural interiors that improve the user experience.

Spatial Organisation and Community Use

The complex contains the OSSTF headquarters along with two floors of leasable office space. At its centre, a large atrium connects the building’s different functions. The atrium brings in natural light, offers views to the outside, and encourages informal interaction between staff and visitors. Shared facilities, including a café, terrace, and event space, are open to tenants as well as community groups, which strengthens the building’s public role.

Energy and Carbon Strategies

The design team integrated several strategies to reduce energy demand and cut emissions. Operable windows with sensors provide natural ventilation, and the atrium helps to expel used air. By placing enclosed offices inboard and open work areas along the perimeter, the architects maximised daylight and reduced the need for artificial lighting. Heating and cooling come from a geo-exchange system paired with drain-water heat recovery, while a rooftop solar array supplies around a quarter of the building’s electricity.

As a result, the building achieves an 84 per cent reduction in greenhouse gas emissions, a 60 per cent reduction in thermal energy use, and a 63 per cent cut in overall energy consumption compared with a conventional office building.

Biophilic Design and Wellbeing

The design also pays close attention to occupant wellbeing. Timber surfaces, fresh air, and daylight create a healthier indoor environment. A feature stair, highlighted by a waterfall-inspired timber wall, encourages staff and visitors to walk rather than use lifts. By linking architectural form with natural elements, the building applies biophilic design principles to support both physical and mental health.

The OSSTF/FEESO Headquarters and Multi-Tenant Complex shows how architects can apply mass timber and integrated sustainability measures in office design. The project reduces environmental impact, supports flexible use, and creates a healthier workplace, offering a clear example of sustainable architecture in practice.

Source: v2com / Moriyama Teshima Architects
Photos: Tom Arban