Mini Design Series: The Mid-rise Building Part II
onespace has been recognized many times for our mid-rise condominium design capabilities.This month we are diving into what makes these projects so successful in a two-part blog series. We will explain what mid-rise buildings are, and other aspects that go along with prep and planning.
Part 2] What key design factors shape a mid-rise and what are some of the challenges?
As land opportunities along major city streets become available for mid-rise developments, so does growth to intensify employment opportunities for local residents and business owners alike. Many municipalities require the inclusion of retail uses within the ground floor of mid-rise buildings to set the stage for this opportunity. The result typically helps to animate the sidewalk with new shopping destinations, cafes, restaurants and coffee shops. This approach brings new street activity to established neighbourhoods.
In addition, cities often require mid-rise developments be placed to provide wide, tree-lined sidewalks and accommodate outdoor patios along the ground floor to further enhance the quality and enjoyment of the retail uses located there. This also widens the public right-of-way to buildings located on the opposite side of the street increasing views to the sky and natural sunlight penetration while minimizing shadows. It is for this reason the height of base of the building or “street wall” is set at a maximum of 6 Storeys. Floors located above 6 Storeys are set back by 1.5m from the lower floors to reduce visual impact from the street. It is this variation of height and stepping which characterizes the geometry of a mid-rise building best.
Most mid-rises are no taller than 11 Storeys and not less than 3 Storeys. These height restrictions and set backs at various floor levels work together to achieve a fit within existing neighbourhoods by balancing the height and mass of the new development with that of existing houses. To help transition this height and mass to the scale of the existing houses, cities require the application of an “angular plane” to reduce mass as the building rises above grade. The angular planes are often applied at an angle of 45 degrees from several property lines bounding the site and give the mid-rise its characteristic “stepped” profile.
Cities require unoccupied roof areas to be treated as “green” roofs to comply with environmental initiatives set by local and regional authorities. In most cases, and as the building steps back to comply with angular planes, large private and public outdoor amenity spaces or terraces are created for the occupants. Such spaces are required for zoning purposes and can often lead to the inclusion of roof-top amenity spaces at the top floor providing views to the city beyond.
Although mid-rise developments have become a viable opportunity to help grow our cities, they often present challenges to suit construction budgets and create profit opportunity for the developer. Balancing urban design guidelines, construction cost, affordability for the purchaser and profit incentives for the developer is of particular focus when considering the mid-rise housing type. Provision of affordable housing is becoming an increasing issue in most Canadian cities and while the definition of “affordable” can be debated, it is best if all new forms of housing become available to the majority of our population. Mid-rise buildings may be best suited to address this challenge as land opportunities to revitalize existing neighbourhoods may be greater in number than those available for hi-rise building forms or the sprawling subdivisions which consume the “dark unlit” areas beyond our city borders at great expense to the natural environment.