1. Cité du Grand Parc (2016) – Bordeaux, France

Lacaton & Vassal; Frédéric Druot Architecture; Christophe Hutin Architecture

• Grand Parc was created to house working-class families, newcomers as well as those displaced from the city centre as a result of slum clearance after the second world war.
• 3 of the towers were slated for demolition until Frederic Druot, Anne Lacaton and Jean Phillipe proposed an alternative solution. The renovation included adding insulation and pre-fabricated, 3.8m concrete ‘winter gardens’ (balconies) to each of the 538 units.
• The winter gardens are enclosed with translucent polycarbonate sliding panels and reflective insulated curtains. The placement of insulation and winter gardens help to reduce energy consumption through passive solar heat gain during the winter months, while the foil curtains reflect heat during the summer months.
• There is no thermal bridging, as the new structure is independent of the existing building.
• At around $75,000 CAD per unit, the renovation cost roughly half as much as a new-build scheme. Only half of the budget was spent on the facades; the rest was dedicated to more general upgrading on the interiors of the towers.
• Rents have remained stable and none of the tenants were displaced during construction.

2. Central Hill Estate: Alternative to Demolition (2016) – London, England

Architects for Social Housing (ASH)

• Built in the late 1960s as an alternative to housing families in tower blocks, Central Hill Estate is a low-rise, high density neighbourhood of over 1,200 residents located in south London.
• The entire estate was slated for demolition through a Council-led ‘regeneration’ plan that will almost eliminate the affordable housing stock, when Architects for Social Housing (ASH), a volunteer based group of architects and designers formed and proposed an alternative plan to the loss of the thousands of homes.
• The plan included increasing the housing capacity of the estate by 40%-50% through strategically placed infill housing and ‘roof extensions’ – pre-fabricated lightweight construction of units to be added to the roofs of existing low-rise buildings. The new housing would include a mix of units sold and rented to the private market to offset the cost of the long neglected repair and maintenance of the existing buildings.
• The architects hired by Council began their consultation with the residents by posting on their Twitter account a photograph taken of the estate at night with the caption: ‘Would you walk down this alleyway!’ As a clever response, ASH published stereotypical negative statements made about estates juxtaposed with photographs highlighting the beauty and diversity of Central Hill.
• The ASH plan was costed at a total of $130,000,000 CAD, less than half the cost of Council’s proposed plan to demolish and rebuild the number of existing homes.

3. Tower Renewal (2016) – Toronto, Canada

ERA Architects

• Nearly one million people in the Greater Toronto Area live in approximately 2,000 concrete residential tower blocks which were built between 1945 and 1984. These towers were originally intended to promote social progress, alleviate pressures on infrastructure and services in crowded downtown cores, and provide residents with access to green space. Today, ‘tower in the park’ housing accounts for nearly half of Toronto’s rental housing, one of the most unaffordable housing markets in Canada.
• Most of the buildings themselves are in poor repair, are below today’s energy efficiency and accessibility standards, have underused green space and lack community amenities.
• Graeme Stewart of ERA Architects, and some local partners set up a non-profit organization independent of the City Department to manage what has become the Tower Renewal Partnership (TRP). TRP conducts feasibility studies at the unit, building and campus scales, publishes reports and lead initiatives to improve these tower in the park neighbourhoods.
• The Tower Renewal Vision has 3 phases:
  • Energy retrofits and improvements to existing housing
  • The provision of new community amenities and programming
  • Better integration of tower neighborhoods into the city through infill development new recreational opportunities and improved transit connection.
• To modernize the ageing housing stock while maintaining affordability, the Tower Renewal Partnership has proposed Passive House and mechanical retrofits to high-rise apartments in order to reduce energy consumption and lower operating costs.