The Intent of The Design
The proposed low-energy housing scheme aims at providing, with a density of 75 units/ha, a type of dwelling which has some of the essential characteristics of a single-family house; mainly autonomy and identity, front and rear gardens or large terraces, greenhouses, two-level dwellings for the larger families and is a scheme that can respond to the living needs of families with or without children, the elderly and the physically handicapped. Our scheme establishes a horizontal separation between pedestrian and motor vehicle traffic. All cars circulate and park underground and may approach all six hydraulic elevators and stairs which, at the upper levels are linked to the dwellings by elevated walkways, and at ground level are connected to the dwellings by paved pedestrian walkways. Only emergency vehicles, moving trucks and bicycles may enter at ground level and use the pedestrian walkways. Although the underground parking solution may suggest a cost increase, it is evident to us that a ground-level parking solution is incompatible with the spirit of this type of housing at the present density level of 75 units/ha and in disregard of the diverse needs of the housing environment. The estimated population of the complex is approximately 626 people of whom 326 are children. A ground floor parking and vehicular traffic solution would leave very little outdoor common space and raise a serious problem of safety for children. The proposed solution offers common outdoor spaces between building blocks, providing areas of shade and sunshine and consisting of green strips and paved walkways which would have an urban character. These linear spaces are linked to a larger focusing space at the centre, a sort of "Agora", a meeting place for adults and children including a playground. This space is directly connected to the adjacent park. The site plan arrangement is essentially motivated by the following considerations:
Best orientation in relation to the sun for energy conservation.
Minimum visual obstruction by other buildings.
Privacy of dwellings and their outdoor spaces.
Common outdoor spaces free from motor vehicle traffic and leading directly to the park.
Energy Conservation
All dwellings face south to intercept the sun's rays during hottest hours. Shifting of dwellings is minimized to avoid projection of shadows over sun collectors. Distances between building blocks is such that there is never a shadow on another block. The slope angle of solar panels is 60° being virtually perpendicular to the sun's rays on January 21 in Toronto's latitude. Privacy screens between terraces are in canvas which is removable in winter to avoid shadow projections. These lateral screen frames will support horizontal sun protection shades in summer. Space heating and domestic hot water is provided by a combination of solar heating and individual gas furnaces. Hot air collected from solar panels is transferred to adjacent rock heat storage by natural thermo-siphoning. In summer a damper diverts the hot air at the top of the collector to the outside while transferring heat to the hot water serpentines. The air is forced by the furnace fan through the rock heat storage and further through the conventional dwelling ductwork. Based on calculations, the solar heating system will produce a minimum of 50% of the energy required for space heating and a substantial amount of the domestic hot water required. Additional passive conservation features for winter and summer are integrated in the design:
In summer time the south exposed greenhouses are converted into open terraces by sliding away the exterior set of glass doors.
Increased thickness (lightweight concrete) of greenhouse floor provides additional thermal inertia.
Upper glazing of greenhouse has sun-control horizontal blinds and ventilation windows.
In summer, north-south cross ventilation is increased by the natural draught of the solar panels' air convection.
In winter the greenhouse will produce some humidity for the dwelling.
The metal open-fireplace recessed in rock heat storage is a one-way transfer type.
Minimum size for north exposed windows.
Triple glazing for all windows.
Air lock entrance vestibule.
Exterior walls and roof with exterior polyurethane slab insulation, (covered by special stucco on fibreglass mesh for walls) provides maximum thermal inertia in addition to inertia of interior common walls, concrete stairs and floor.
The Structural System
Throughout, the construction technique is based on a standardization of building components. The structural system of the dwellings consists of pre-stressed "Flexicore" type slabs for floors and roofs with clear spans of 6000 mm and 7500 mm supported by typical demising shear walls. Shear walls are in reinforced concrete poured on site, including foundation walls, underground parking garage, 1st level, front and rear portions of 2nd level. Remainder of upper walls are in engineered concrete block masonry. Interior stairs are all identical (92 units) and made of two-piece precast concrete. Sectional planters are also in precast concrete. Exterior access stairs and elevated walkways are in lightweight steel-tube frame construction with wood-board flooring integrating structure members, railings and wire mesh guards. All interior partitions are non-bearing made of metal studs and Gyproc. Dining rooms and kitchens have a 2100 mm drop ceiling to accommodate air ducts and plumbing.
(From competitor's text)
This submission was recognized primarily for the following features: it demonstrated a strong commitment to the principles of energy conservation, both passive and active; it showed an excellent understanding of unit planning, both interior and exterior; it showed an excellent understanding of construction principles and it was extremely effectively presented. The jury recognized that the provision of active solar energy conservation devices went beyond what was called for by the competition requirements, but noted that the submission readily allowed these devices to be considered optional and did not depend fundamentally on them. Moreover, the unit planning, in the opinion of the jury, showed a sensitive appreciation of issues of access, furniture arrangement and family living. Then too, the simple system of cross-walls and stacked units offered reasonably practical potential for economical construction. The clear and strong drawings made all the features of the submission readily understandable to the jury members. Despite these positive qualities, the submission worried some jury members in two important respects. First of all, the placing of all the parking underground, in a labyrinthine garage, was considered unworkable. And the fact that access from this garage to the units above was provided by collectively-owned elevators, was thought to be impractically expensive and too difficult to supervise and administer in a complex of only 150 units. The jury was split over the impact of this underground parking on the site planning. Some jurors felt the large amount of landscaped open space it yielded was an asset, while others found it wasteful and socially difficult to administer. The dissatisfied jurors would have preferred a higher proportion of private, rather than collective landscaped open space.
(From jury report)
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- Site Plan
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