medium density housing
overwhelmingly triplex, two to three storeys

The History of the Montreal Triplex.

directly accessed from the exterior, exterior staircases, maximize rentable floor area

spiral stairs

Lloyd Alter Treehugger:

“But it is an odd choice of design for a city with so much snow; how did it happen? According to one article in Urbanphoto, it was the building codes and zoning bylaws of the time.

“Architect Susan Bronson, who teaches at the Université de Montréal, notes that turn-of-the-century building codes, designed to improve living conditions, played a big role in reinforcing the dominance of the plex. In Montreal and the suburb of St. Louis (now Mile End), lot sizes were increased from 20 by 60 feet to 25 by 100 feet and laneways were built in between blocks to service new apartments. Setbacks were mandated on newly-built residential streets, indirectly encouraging the use of outdoor staircases as a space-saving measure.

The problem is that the mandated setback was just a bit short of what was required to run a straight stair, so many of them go through extraordinary contortions to get the stairs in the limited distance. Others feel as steep as ships ladders.”

In effect, these regulations created an official template for the plex. Contractors were able to quickly and cheaply build high-quality housing. At the same time, the city’s population swelled with new migrants. “There was a really, really urgent demand for housing,” said Bronson. “A typology developed out of what was essentially a building code.”

There are other theories about why the housing got built this way; some note that it saved the landlords the cost of heating the interior common areas, and that it was probably better in case of fire. There is even a theory that it was an “anti-adultery precaution imposed by the Roman Catholic Church”- no sneaking around inside. But whatever the reason, it results in lovely apartments, usually L shaped to allow light into every room.

“By the turn of the century, Montreal’s working-class neighbourhoods had developed a distinctive housing form known as the ‘superposed’ flat. These were two- or more commonly three-storey structures, with an apartment on each floor, exterior staircases, and balconies both at the front and the back. In areas like the Plateau, the superposed flats not only created an unusually dense urban form but provided owners with an opportunity to live on one floor and generate welcome additional income by renting out the others. ‘In the nineteenth century’, according to a CMHC study on Montreal’s housing, ‘the appeal of real estate ownership resided in the potential rental income, rather than the propriety of one household to own its own dwelling.’ This model, which acknowledges the high carrying costs of urban houses, was also common in cities like Philadelphia and Glasgow, and continues to find currency in the guise of basement apartments and secondary suites.”

   
Subsection IV
Means of Egress

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11-018-3, a. 26.

29. The requirements of Sections 9.9.4.2., 9.9.4.4. and 9.10.8.8. of Division B of the Code do not apply to an exterior passageway that does not serve as the only means of egress for a suite where the other means of egress is independent of the first.

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11-018, a. 29.
 
29.1. Notwithstanding Section 9.8.3.1. of Division B of the Code, an exterior stairway that serves only dwelling units and is not their only means of egress may turnin its entirety or turn in one or more parts if:

1° it serves a level not more than one story above the second floor;

2° it serves not more than 2 dwelling units per floor;

3° it has equal treads of not less than 225 mm when measured at 500 mm from the narrowest end;

4° the rotation between 2 levels is in the same             direction. 

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11-018-3, a. 27.

29.2. Notwithstanding Section 9.8.3.1. of Division B of the Code, a spiral staircase authorized under paragraph 3 or 4 of Section 9.8.4.5. of Division B of the Code may be rotatable in its entirety or be rotatable in one or more parts where each rotating part permits rotation of at least 180 degrees.    

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11-018-3, a. 27.

29.3. Notwithstanding subsection 1 of section 9.8.2.1. of Division B of the Code, where a dwelling unit has 2 or more means of egress, one of the means of egress may be an exterior stairway with a minimum clear width of 760 mm, provided that:

1° the stairway serves only dwelling units;

2° the stairway serves not more than 2 dwelling units per floor area.

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11-018-3, a. 27.

29.4. Notwithstanding subsection 1 of Section 9.8.4.3. of Division B of the Code, curved steps on an exterior exit stairwayserving not more than two dwelling units per floor area does not need to comply with Section 3.4.6.9. of Division B of the Code if they meet the following conditions:

1° they have a tread of not less than 150 mm measured at the narrowest point;

2° they have a tread of at least 230 mm measured at 300 mm from the narrowest point;

3° they turn in the same direction.

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11-018-3, a. 27.

Last update: January 23th, 2020

Translated by author

Sous-Section IV
Moyens d’Évacuation

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11-018-3, a. 26.

29. Les exigences des articles 9.9.4.2., 9.9.4.4. et 9.10.8.8. de la division B du Code ne s’appliquent pas à un passage extérieur qui ne sert pas d’unique moyen d’évacuation pour une suite dont l’autre moyen d’évacuation est indépendant du premier.

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11-018, a. 29.

29.1. Malgré l’article 9.8.3.1. de la division B du Code, un escalier extérieur qui ne dessert que des logements et qui ne constitue pas leur seule issue peut être tournant en totalité ou être tournant en une ou plusieurs parties aux conditions suivantes:

1° il dessert un niveau situé à au plus un étage au-dessus du premier étage;

2° il dessert au plus 2 logements par étage;

3° il comporte des girons égaux d’au moins 225 mm, lorsque mesurés à 500 mm de l’extrémité la plus étroite;

4° la rotation entre 2 niveaux s’effectue dans le même sens.

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11-018-3, a. 27.

29.2. Malgré l’article 9.8.3.1. de la division B du Code, un escalier hélicoïdal autorisé en vertu des paragraphes 3 ou 4 de l’article 9.8.4.5. de la division B du Code, peut être tournant en totalité ou être tournant en une ou plusieurs parties lorsque chaque partie tournante permet de tourner d’au moins 180 degrés.      

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11-018-3, a. 27.

29.3. Malgré le paragraphe 1 de l’article 9.8.2.1. de la division B du Code, lorsqu’un logement comporte au moins 2 moyens d’évacuation, l’un d’eux peut être un escalier extérieur d’une largeur libre minimale de 760 mm, aux conditions suivantes:

1° l’escalier ne dessert que des logements;

2° l’escalier dessert au plus 2 logements par aire de plancher.

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11-018-3, a. 27.

29.4. Malgré le paragraphe 1 de l’article 9.8.4.3. de la division B du Code, il n’est pas obligatoire que les marches dansantes d’un escalier d’issue extérieur desservant au plus deux logements par étage soient conformes à l’article 3.4.6.9. de la division B du Code, si elles répondent aux conditions suivantes:

1° elles ont un giron d’au moins 150 mm mesuré au point le plus étroit;

2° elles ont un giron d’au moins 230 mm mesuré à 300 mm du point le plus étroit;

3° elles tournent dans la même direction.

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11-018-3, a. 27.

Dernière mise à jour : 23 janvier 2020

3.4.6.9. Curved Flights in Exits

1) Exit stair flights shall consist solely of

a) straight flights, or

b) curved flights complying with Sentence (2).

2) A curved flight used as an exit shall have

a) a handrail on each side,

b) a minimum run of 240 mm,

c) a run that conforms to Article 3.4.6.8. when measured at a point 300 mm from the centre line of the handrail at the narrow end of the tread, and

d) an inside radius that is not less than twice the stair width.

3) Tapered treads shall have a consistent angle and uniform run and rise dimensions in accordance with the construction tolerances stipulated in Article 3.4.6.8. when measured at a point 300 mm from the centre line of the handrail at the narrow end of the tread.

4) All tapered treads within a flight shall turn in the same direction.

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9.8.2.1. Stair Width

1) Except as provided in Sentence (2) and Article 9.8.4.7., required exit stairs and public stairs serving buildings of residential occupancy shall have a width of not less than 900 mm.

2) Exit stairs serving a single dwelling unit or a house with a secondary suite including their common spaces shall have a width of not less than 860 mm.

3) Except as provided in Article 9.8.4.7., required exit stairs and public stairs serving buildings of other than residential occupancy shall have a width of not less than the greater of

a) 900 mm, or

b) 8 mm per person based on the occupant load limits specified in Table 3.1.17.1.

4) Except as provided in Article 9.8.4.7., at least one stair between each floor level within a dwelling unit, and exterior stairs serving a singledwelling unit except required exit stairs, shall have a width of not less than 860 mm.

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9.8.3.1. Permitted Configurations

(See Notes A-9.8.3.1. and A-9.8.4.)

1) Stairs in buildings other than dwelling units and houses with a secondary suite, including their common spaces, shall consist of

a) straight flights,

b) except as provided in Sentence (4), curved flights, or

c) except as provided in Sentence 9.8.4.7.(2), spiral stairs.

2) Stairs within dwelling units and houses with a secondary suite, including their common spaces, shall consist of

a) straight flights,

b) except as provided in Sentence (4), curved flights,

c) except as provided in Sentence 9.8.4.7.(2), spiral stairs,

d) except as provided in Sentence (3), flights with rectangular treads and winders, or

e) flights with a mix of rectangular and tapered treads.

3) Only one set of winders described in Article 9.8.4.6. shall be permitted between floor levels.

4) Curved flights in exits shall comply with Sentence 3.4.6.9.(2).

5) All tapered treads within a flight shall turn in the same direction.

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9.8.4.3. Dimensions of Tapered Treads

(See Note A-9.8.4.)

1) Except as provided in Sentence (2) and Articles 9.8.4.6. and 9.8.4.7., tapered treadsshall have a run that

a) is not less than 150 mm at the narrow end of the tread, and

b) complies with the dimensions stated in Table 9.8.4.2. when measured at a point 300 mm from the centre line of the handrail at the narrow end of the tread.

2) Tapered treads in required exit stairs shall conform to the requirements in Article 3.4.6.9.

3) The depth of a tapered tread shall be not less than its run at any point and not more than its run at any point plus 25 mm.

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9.8.4.5. Uniformity of Runs in Flights with Mixed Treads within Dwelling Units

1) Except as provided in Sentence (2) and Article 9.8.4.6., where a flight of stairs consists of both tapered treads and rectangular treads, all the treads shall have a uniform run when measured at a point 300 mm from the centre line of the inside handrail.

2) Where tapered treads are located at the bottom of a mixed-tread flight, the run of the tapered treads when measured at a point 300 mm from the centre line of the inside handrail is permitted to exceed the run of the rectangular treads.

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9.9.4.2. Fire Separations for Exits

1) Except as provided in Sentences (2) and (5) and Article 9.9.8.5., every exitother than an exterior doorway shall be separated from each adjacent floor area or from another exit

a) where there is a floor assembly above the floor area, by a fire separation having a fire-resistance rating not less than that required for the floor assembly above the floor area (see Article 9.10.9.10.), and

b) where there is no floor assembly above the floor area, by a fire separation having a fire-resistance rating not less than the greater of

i) that required by Subsection 9.10.8. for the floor assembly below, or

ii) 45 min.

2) Where an exit is located in a house with a secondary suite including their common spaces, the exit shall be protected by a continuous smoke-tight barrier of not less than 12.7 mm thick gypsum board installed on

a) both sides of walls separating the exit from the remainder of the building, and

b) the underside of floor-ceiling framing separating the exit from the remainder of the building. (See Sentence 9.10.9.3.(2) for closures.)

3) A fire separation common to 2 exits shall be smoke-tight and not be pierced by doorways, duct work, piping or any other opening that may affect the continuity of the separation.

4) A fire separation that separates an exit from the remainder of the building shall have no openings except those for electrical wiring, noncombustibleconduit and noncombustible piping that serve only the exit, and for standpipes, sprinkler piping, exit doorways and wired glass and glass block permitted in Article 9.9.4.3.

5) The requirements in Sentences (1) and (2) do not apply to an exterior exit passageway provided the passageway has not less than 50% of its exterior sides open to the outdoors and is served by an exit stair at each end of the passageway.

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9.9.4.4. Openings Near Unenclosed Exterior Exit Stairs and Ramps

1) Unprotected openings in exterior walls of the building shall be protected with wired glass in fixed steel frames or glass block conforming to Articles 9.10.13.5. and 9.10.13.7., where

a) an unenclosed exterior exit stair or ramp provides the only means of egress from a suite and is exposed to fire from unprotected openings in the exterior walls of

i) another fire compartment, or

ii) another dwelling unit, ancillary space or common space in a house with a secondary suite, and

b) unprotected openings in the exterior walls of the building are within 3 m horizontally and less than 10 m below or less than 5 m above the exitstair or ramp.

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9.9.10.1. Egress Windows or Doors for Bedrooms

1) Except where the suite is sprinklered, each bedroom or combination bedroom shall have at least one outside window or exterior door openable from the inside without the use of keys, tools or special knowledge and without the removal of sashes or hardware. (See Article 9.5.1.2. and Note A-9.9.10.1.(1).)

2) The window referred to in Sentence (1) shall

a) provide an unobstructed opening of not less than 0.35 m2 in area with no dimension less than 380 mm, and

b) maintain the required opening during an emergency without the need for additional support. (See Note A-9.9.10.1.(2).)

3) Where a window required in Sentence (1) opens into a window well, a clearance of not less than 760 mm shall be provided in front of the window. (See Note A-9.9.10.1.(3).)

4) Where the sash of a window referred to in Sentence (3) swings towards the window well, the operation of the sash shall not reduce the clearance in a manner that would restrict escape in an emergency.

5) Where a protective enclosure is installed over the window well referred to in Sentence (3), the enclosure shall be openable from the inside without the use of keys, tools or special knowledge of the opening mechanism.

Les 4 Arbres

Atelier Raouf Boutros Architect (2009)
4878 Rue Henri-Julien, Montreal, QC

Height: 
Use: 
Floor Area: 
Construction:
Stair: 
Sprinklered:

“This project located on the P l a t e a u - M o n t - Royal, Henri-Julien Street, was to redevelop a backyard a backyard warehouse and sheds into an affordable housing an affordable housing project for young households and young households and individuals. And what's special is that is that the project is not visible from the street. from the street. Access to the premises is possible from a from a porte cochere."

Le Jardinier

Adhoc Architectes (2018)
3160 Rue de Rouville, Montreal, QC

Height: 4 storeys (+ half-sunken basement)
Use: 16 dwelling units
Floor Area: ?? m²
Construction: Protected Wood Frame
Stair: Wood Frame (interior), Galvanized Steel (exterior stair)
Sprinklered: ?

The “Gardener” is a modern reinterpretation of the historic Montreal triplex. The building is four storeys with a half-sunken basement and an efficient egress strategy. This project internalizes the front stair to serve two units per floor whereas traditional triplexes have slight setbacks from the property line to accomodate their exterior stairs. The design also evolves the traditional strategy of a spiral fire escape at the rear with a code-compliant metal stair accessed from generous shared patios.

NMBHD

Jean-Verville architecte (2020)
Private address - Rosemont, Montreal, QC

Height: 3 storeys (+ half-sunken basement)
Use: 3 dwelling units
Floor Area: ?? m²
Construction: Wood Frame (Part 9)
Stair: within dwelling units
Sprinklered: No (Part 9)

Another project reinterpreting the triplex, this building wraps and stacks three dwelling units around each other. Each unit is independently accessed directly from grade and circulation is internalized within each fire-separated unit. The project falls within Part 9 (Small Buildings and Housing) of the code such that code provision 9.9.9.1, sentence (2) is used to permit single egress construction at three storeys height, in which balconies or operable windows with a sill height no more than 7m above adjacent ground level function as second egress.

Habitations Saint-Michel Nord

Saia Barbarese Toupouzanov Architectes (2020)
8550 Allée Léo-Bricault, Montreal, QC

Height:
Use:
Floor Area:
Construction:
Stair:
Sprinklered:

“Over the last three years, the architectural firm of Saia Barbarese Topouzanov has revitalized Les Habitations Saint-Michel Nord, a 185-unit social housing complex in Montreal’s Saint-Michel neighbourhood. Designed by Montreal architect Philip Bobrow in the early 1970s, when brutalism was in vogue, the complex now features plenty of light and colour. It has become a joyful part of the landscape, a dignified and respectful environment for all residents.”