Ground floor and public realm

Adeyemi begins week five with a walk of exactly one hundred steps along the avenue, from the café on the far side of the street to the corner of the studio site. She asks the students to note, step by step, what they can see: a door, a window with something behind it, a blank wall, a garage door, a parking lot. On the café side, almost every step passes a window or a door. On the site's side, the steps pass the parking garage's concrete wall, the parking lot and the side of the Harland Building. 'Most people will never enter your building,' she says. 'They will walk past it every day for fifty years. For them, the building is its ground floor.' This lesson is about the ground floor and its relationship with the public realm.

The public realm

The public realm is the network of spaces open to everyone: streets, sidewalks, squares, parks, lanes, transit stops and the publicly accessible interiors of buildings such as lobbies, shops and libraries. Its quality depends on the buildings that line it as much as on its own design. The Danish architect and urbanist Jan Gehl, who spent decades observing how people use public spaces, found that people walk further, linger longer and feel safer along building fronts with many doors, windows, details and activities at eye level, and that they hurry past long blank walls. He summarized his findings in the phrase that life between buildings matters as much as the buildings themselves.

The ground floor is where a building contributes to the public realm or takes from it. A ground floor with active uses, generous windows, frequent doors, shelter and places to sit adds to the street. A ground floor of blank walls, parking, service doors and dark glass subtracts from it, however handsome the floors above.

Active frontage

Active frontage is a ground floor edge where the inside and the outside interact: people can see in and out, doors open onto the street, and activity spills onto the sidewalk. Gehl and others have graded frontages from active to inactive. An active frontage has small units with many doors, perhaps fifteen to twenty-five per hundred metres of street, transparent windows, varied functions and details that reward a slow walk. An inactive frontage has large units with few doors, little or no transparency and no variety. Most zoning codes for downtowns now require a minimum share of active uses and transparent glazing on main streets, as the studio code does.

# Ground floor frontage check against the studio code (avenue frontage of 40 m)
front = 40
segments = [
    # name, length along the avenue (m), active use?, glazed length between 0.6 and 3 m above the sidewalk
    ("cafe at the corner", 12.0, True, 10.5),
    ("grocery", 19.0, True, 15.0),
    ("grocery entrance", 3.0, True, 2.4),
    ("electrical room", 4.0, False, 0.0),
    ("garbage room door", 2.0, False, 0.0),
]
length = sum(l for _, l, _, _ in segments)
assert abs(length - front) < 0.01
active = sum(l for _, l, a, _ in segments if a)
glazed = sum(gl for _, _, _, gl in segments)
doors = 3                                    # cafe, grocery, grocery entrance
print(f"active frontage {active:.1f} of {front} m = {active / front:.2f} (code: at least 0.60)")
print(f"transparent frontage {glazed:.1f} m = {glazed / front:.2f} (code: at least 0.60)")
print(f"doors per {100} m of frontage: {doors / front * 100:.1f}")
for name, l, a, gl in segments:
    print(f"   {name:20s} {l:5.1f} m {'active' if a else 'inactive':8s} glazed {gl:5.1f}")

active frontage 34.0 of 40 m = 0.85 (code: at least 0.60)
transparent frontage 27.9 m = 0.70 (code: at least 0.60)
doors per 100 m of frontage: 7.5
   cafe at the corner    12.0 m active   glazed  10.5
   grocery               19.0 m active   glazed  15.0
   grocery entrance       3.0 m active   glazed   2.4
   electrical room        4.0 m inactive glazed   0.0
   garbage room door      2.0 m inactive glazed   0.0

Wren's first ground floor plan puts the electrical room and a garbage room on the avenue, because the utility company's transformer connection is on that side. The check shows that the frontage still passes the code, with about 0.85 of it active and about 0.70 transparent, but the numbers hide a problem: the inactive segments sit together at the west end, next to the Harland Building, creating a blank stretch 6 m long where the street most needs a link between the old building and the new. And three doors on 40 m is few by Gehl's standard. Adeyemi asks her to move the electrical room and garbage to the lane, where they belong, negotiate with the utility, and add a second door to the grocery and a door to a small shop or a flower stand at the west end.

Ground floor height and level

Ground floors need height. The studio code requires at least 4.5 m floor to floor, and the students choose 4.8 m to match the Harland Building and leave room for the grocery's ducts and refrigeration lines. Height gives shopfronts presence, lets light deep into the plan, accommodates mezzanines and makes the space adaptable to future uses.

The ground floor should also meet the sidewalk at the same level. A floor raised a few steps above the sidewalk, common in older buildings, creates a barrier for wheelchair users, people with strollers and delivery carts, and needs ramps that eat into the sidewalk or the interior. On the studio site, the sidewalk falls about 300 mm from the corner to the west end. Callum proposes stepping the ground floor slab by 150 mm between the café and the grocery and grading the entrances so that every door has a level threshold, with an accessible slope of no more than 1 in 20 along the shopfront where needed. Residential lobbies are an exception where a few steps can give privacy, but the main entrance must still be accessible.

Shopfronts and windows

A good shopfront lets people see the goods and activity inside, frames them with a sturdy base and a sign band, and has a door that is easy to find. In the warehouse district, the historic shopfronts have a pattern: a low base of stone or wood, large glass panes divided by slender mullions, a transom above the door, a sign band and a cornice or canopy marking the top of the ground floor. New shopfronts need not copy it, but the elements serve real purposes. The base protects the glass from snow and salt and gives a place to lean; the transom lets daylight deep into the shop; the sign band gives tenants a consistent place for their names.

Glass must be clear to be transparent. Tinted, reflective or frosted glass, and windows covered with posters or shelving, defeat the purpose. The studio code measures transparency between 0.6 and 3 m above the sidewalk, the zone a passerby's eyes actually see. The grocery's layout matters here: if the shelving faces the windows, the street sees the backs of cereal boxes. Riverlot's grocer agrees to put the produce displays and checkout along the avenue windows and the storage at the back.

Entrances

Entrances are where the public realm and the building meet. Each use in the studio building needs its own: the café at the corner, the grocery on the avenue, the residential lobby on Tessier Street and the Foundry Collective's showroom farther along Tessier. Entrances should be easy to find, sheltered from the weather, lit at night and wide enough for the flows they serve. A recessed entrance, set back from the facade, gives shelter and a place to shake off snow, but a recess deeper than about 1.5 m can become a hiding place or a shelter for people sleeping rough, which raises questions of design and of compassion that Joon-ho's interview with the shelter worker brought into the studio.

The residential lobby deserves particular care. It is the front door of sixty-five households, and residents will pass through it several times a day. A lobby that is visible from the street, with clear glass, good lighting, a bench and mailboxes or a parcel room in view, is welcoming and safe. It should be close enough to the elevators that residents carrying groceries do not walk far, and it needs a vestibule with two sets of doors to keep winter air out.

Shelter, climate and winter

In a northern city, the ground floor must make the sidewalk usable in every season. Canopies and awnings over entrances and shopfronts protect people from rain and snow and give shade in summer. They should project at least 1.5 to 2 m, be high enough to clear signs and people, about 3 m above the sidewalk, and drain away from the walking zone. The studio building's south face on the avenue gets the sun all day, so a café terrace there can be used from April to October, and on sunny winter days, with the building behind it blocking the northwest wind.

Wind is a real concern for buildings taller than their neighbours. When wind strikes a tall face, part of it is deflected down to the street, accelerating around the base and corners. The studio building is about as tall as the Harland Building, so the effect should be modest, but the stepped upper floors, the canopy along the avenue and the trees in the furnishing zone all help. Snow must have somewhere to go: plows push it to the curb, and the building's canopies and roof drains should not drop snow and ice onto the sidewalk. Heated sidewalks, used in some downtown areas, are a costly but effective option at entrances.

The corner

The corner of the avenue and Tessier Street is the building's most important point of contact with the city. The students test several treatments: a sharp corner with the café's glass wrapping around it; a chamfered corner with the café door on the diagonal; and a recessed corner where the ground floor is set back under the floors above to widen the sidewalk. Wren's chamfer, 3 m across, gives the café a door on the diagonal facing the intersection, widens the space where people wait to cross, and echoes the chamfered corners of two historic buildings nearby. Above it, the residential floors hold the corner, so the street edge stays continuous.

Lanes and the back of house

The ground floor's lane side holds the building's services: the shared loading bay, garbage and recycling rooms, the bike room entrance, the Foundry Collective's freight door and electrical and water service rooms. A good lane side is organized, durable and safe: doors are recessed or protected by bollards from turning trucks, lighting is generous, and garbage is inside the building, not in dumpsters on the lane. The Foundry Collective's large freight door can open in summer, letting the lane see the work inside and turning the service side into a modest public face of its own.

Designing for everyone

The public realm belongs to everyone, and the ground floor should welcome everyone. That means level entrances, doors that open automatically or easily, tactile and visual cues for people with low vision, benches for people who need to rest, lighting that avoids glare and dark corners, and signs that are easy to read. It also means thinking about people who are not customers. Hostile architecture, such as spikes on ledges, slanted benches and bars that prevent lying down, pushes people experiencing homelessness elsewhere without solving anything. Joon-ho proposes instead that Riverlot partner with the shelter nearby to fund outreach and a public washroom accessible from the lane, a modest gesture that the developer agrees to price.

Exercise 5: the ground floor

This exercise takes one and a half weeks.

• Draw the ground floor plan at 1:100, including the sidewalks to the curb, the lane and the edges of the neighbouring buildings.
• Draw elevations of both street frontages at 1:50 with people, signs, canopies and trees.
• Calculate active and transparent frontage and doors per unit of length on each street.
• Draw a detailed section through the avenue shopfront and sidewalk, showing the floor level, canopy, sign band and snow.
• Draw the lane elevation, showing loading, garbage, bike and freight doors and lighting.

Self-critique checklist

• Would I enjoy walking past this building every day?
• Is every entrance level, visible, sheltered and lit?
• Have I moved service rooms off the streets?
• Does the corner do something special?