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Ontario Building Code Ceiling Heights and Minimum Room Sizes

Ontario ceiling heights (2024 Code): 2,300 mm living areas, 2,100 mm basements, 1,950 mm under beams. Bedroom 7 m2, main bedroom 9.8 m2.
living, dining, kitchen over 75% of area
2,300 mm
living, dining, kitchen over 75% of area
basement, over 75% of the basement area
2,100 mm
basement, over 75% of the basement area
min bedroom area, no built-in cabinets
7 m²
min bedroom area, no built-in cabinets
one bedroom per unit, no built-in cabinets
9.8 m²
one bedroom per unit, no built-in cabinets

Last updated

In the 2024 Ontario Building Code, living rooms, dining rooms and kitchens need a ceiling height of 2,300 mm over at least 75% of the required floor area, and basements need 2,100 mm over at least 75% of the basement area, dropping to 1,950 mm under beams and ducts (OBC Div. B Table 9.5.3.1.OBC Div. B Table 9.5.3.1. Room Ceiling Heights — Forming Part of Sentences 9.5.3.1.(1) and (4)Table 9.5.3.1 — Room Ceiling Heights — Forming Part of Sentences 9.5.3.1.(1) and (4) Room or Space | Minimum Heights[1] Living room or space, dining room or space, kitchen or kitchen space | 2,300 mm over at least 75% of the required floor area with a clear height of 2,100 mm at any point over the required area…). Bedrooms must be at least 7 m², and one bedroom per dwelling unit at least 9.8 m², both slightly less with built-in cabinets (9.5.3D.1.OBC Div. B 9.5.3D.1. Areas of Bedrooms(1) Except as provided in Articles 9.5.3D.2. and 9.5.3D.3., bedrooms in dwelling units shall have an area not less than 7m² where built-in cabinets are not provided and not less than 6m^2 where built-in cabinets are provided., 9.5.3D.2.OBC Div. B 9.5.3D.2. Areas of Master Bedrooms(1) Except as provided in Article 9.5.3D.3., at least one bedroom in every dwelling unit shall have an area of not less than 9.8 m² where built-in cabinets are not provided and not less than 8.8 m² where built-in cabinets are provided.).

These rules, in Section 9.5 of Division B, decide whether a basement can be finished as living space and whether a small room can legally be called a bedroom. Your building department confirms what applies, and existing houses may qualify for Part 11 alternatives.

Key heights and sizes at a glance

Room or space Minimum height Minimum area
Living room or space 2,300 mm over 75% of required area; 2,100 mm clear everywhere in it 13.5 m² (11 m² in some small units)
Dining room same as living 7 m² separate; 3.25 m² combined
Kitchen same as living 4.2 m² (3.7 m² in some small units)
Bedroom 2,300 mm over 50%, or 2,100 mm over all 7 m² (6 m² with built-ins)
Main bedroom (one per unit) as bedroom 9.8 m² (8.8 m² with built-ins)
Basement space 2,100 mm over 75%; 1,950 mm under beams and ducts n/a
Secondary suite 1.95 m; 1.85 m under beams and ducting per room type
Hallway width n/a 860 mm (710 mm in limited cases)

Our own summary of Section 9.5. "Some small units" means dwelling units with sleeping accommodation for not more than two people.

Who these rules apply to

Section 9.5 applies to dwelling units intended as someone's year-round principal residence, unless Part 9 says otherwise (9.5.1.0A.OBC Div. B 9.5.1.0A. Application(1) Except as otherwise specified in this Part, this Section applies only to dwelling units that are intended for use on a continuing or year-round basis as the principal residence of the occupant.). Areas and heights are measured between finished surfaces (9.5.1.1.OBC Div. B 9.5.1.1. Method of Measurement(1) Except as otherwise specified in this Part, the areas, dimensions and heights of rooms or spaces shall be measured between finished wall surfaces and between finished floor and ceiling surfaces.), and minimum floor areas do not include closets or built-in bedroom cabinets unless the code says so (9.5.1.1A.OBC Div. B 9.5.1.1A. Floor Areas(1) Minimum floor areas specified in this Section do not include closets or built-in bedroom cabinets unless otherwise indicated.). Smaller areas can be accepted if they are shown to be adequate for the intended use, for example with built-in furniture (9.5.1.3.OBC Div. B 9.5.1.3. Lesser Areas and Dimensions(1) Areas of rooms and spaces are permitted to be less than required in this Section provided it can be shown that the rooms and spaces are adequate for their intended use, such as by the provision of built-in furniture to compensate for reduced sizes.).

Ceiling heights

9.5.3.1.OBC Div. B 9.5.3.1. Ceiling Heights of Rooms or Spaces(1) Except as provided in Sentences (2) and (3), the ceiling heights and clear heights in rooms or spaces in residential occupancies and live/work units shall conform to Table 9.5.3.1. (2) Ceiling heights in secondary suites shall be not less than 1.95 m. (3) Clear heights under beams and ducting in secondary suites… sends you to Table 9.5.3.1.OBC Div. B Table 9.5.3.1. Room Ceiling Heights — Forming Part of Sentences 9.5.3.1.(1) and (4)Table 9.5.3.1 — Room Ceiling Heights — Forming Part of Sentences 9.5.3.1.(1) and (4) Room or Space | Minimum Heights[1] Living room or space, dining room or space, kitchen or kitchen space | 2,300 mm over at least 75% of the required floor area with a clear height of 2,100 mm at any point over the required area…. In plain words:

  • Living, dining and kitchen spaces: 2,300 mm over at least 75% of the required floor area, and nowhere in the required area lower than 2,100 mm.
  • Bedrooms: either 2,300 mm over at least half of the required area, or 2,100 mm over all of it. Any part of the floor with less than 1,400 mm of clear height does not count toward the area, which matters under sloped ceilings.
  • Basement spaces: 2,100 mm over at least 75% of the basement area, with 1,950 mm permitted under beams and ducts.
  • Bathrooms and laundry areas above grade: 2,100 mm wherever a person would normally stand.
  • Halls, vestibules and other finished rooms: 2,100 mm.

Two extra rules: in a secondary suite, ceilings must be at least 1.95 m, with at least 1.85 m clear under beams and ducting (9.5.3.1.(2) and (3)OBC Div. B 9.5.3.1. Ceiling Heights of Rooms or Spaces(1) Except as provided in Sentences (2) and (3), the ceiling heights and clear heights in rooms or spaces in residential occupancies and live/work units shall conform to Table 9.5.3.1. (2) Ceiling heights in secondary suites shall be not less than 1.95 m. (3) Clear heights under beams and ducting in secondary suites…). And the area that meets the height must be contiguous with the room's entry, so a tall pocket you can only reach by ducking under a low section does not count (9.5.3.1.(4)OBC Div. B 9.5.3.1. Ceiling Heights of Rooms or Spaces(1) Except as provided in Sentences (2) and (3), the ceiling heights and clear heights in rooms or spaces in residential occupancies and live/work units shall conform to Table 9.5.3.1. (2) Ceiling heights in secondary suites shall be not less than 1.95 m. (3) Clear heights under beams and ducting in secondary suites…). A storage garage needs at least 2 m clear (9.5.3.3.OBC Div. B 9.5.3.3. Storage Garages(1) The clear height in a storage garage shall be not less than 2 m.).

Room sizes

  • Living area: at least 13.5 m², or 11 m² where it is combined with the kitchen and dining area in a unit sleeping not more than two people (9.5.3A.1.OBC Div. B 9.5.3A.1. Areas of Living Rooms and Spaces(1) Living areas within dwelling units, either as separate rooms or in combination with other spaces, shall have an area not less than 13.5 m². (2) Where the area of a living space is combined with a kitchen and dining area, the living area alone in a dwelling unit that contains sleeping accommodation for not more…).
  • Dining: at least 3.25 m² when combined with other space, or 7 m² as a separate room (9.5.3B.1.OBC Div. B 9.5.3B.1. Area of Dining Rooms or Spaces(1) A dining space in combination with other space shall have an area of not less than 3.25 m². (2) Dining rooms not combined with other space shall have a minimum area of 7 m².).
  • Kitchen: at least 4.2 m² including base cabinets, or 3.7 m² in a unit sleeping not more than two people (9.5.3C.1.OBC Div. B 9.5.3C.1. Kitchen Areas(1) Kitchen areas within dwelling units either separate from or in combination with other spaces, shall have an area of not less than 4.2 m² including the area occupied by the base cabinets, except that in dwelling units containing sleeping accommodation for not more than two persons, the minimum area shall be 3.7 m².).
  • Bedrooms: at least 7 m² without built-in cabinets or 6 m² with them (9.5.3D.1.OBC Div. B 9.5.3D.1. Areas of Bedrooms(1) Except as provided in Articles 9.5.3D.2. and 9.5.3D.3., bedrooms in dwelling units shall have an area not less than 7m² where built-in cabinets are not provided and not less than 6m^2 where built-in cabinets are provided.). At least one bedroom in each dwelling unit must be 9.8 m², or 8.8 m² with built-ins (9.5.3D.2.OBC Div. B 9.5.3D.2. Areas of Master Bedrooms(1) Except as provided in Article 9.5.3D.3., at least one bedroom in every dwelling unit shall have an area of not less than 9.8 m² where built-in cabinets are not provided and not less than 8.8 m² where built-in cabinets are provided.). A bedroom space combined with other space needs 4.2 m² (9.5.3D.3.OBC Div. B 9.5.3D.3. Areas of Combination Bedrooms(1) Bedroom spaces in combination with other spaces in dwelling units shall have an area not less than 4.2 m².).
  • Bachelor units: where living, dining, bedroom and kitchen are combined in a unit for not more than two people, the combined area must be at least 13.5 m² (9.5.3E.1.OBC Div. B 9.5.3E.1. Combined Living, Dining, Bedroom and Kitchen Spaces(1) Despite Subsections 9.5.3A. to 9.5.3D.., where living, dining, bedroom and kitchen spaces are combined in a dwelling unit that contains sleeping accommodation for not more than two persons, the area of the combined spaces shall be not less than 13.5 m² .).

Combination rooms. Two areas count as one room if the opening between them is at least 3 m² or 40% of the wall on the dependent side, whichever is larger, with no doors or windows in the opening. If the dependent area is a bedroom, there must be direct passage (9.5.1.2.OBC Div. B 9.5.1.2. Combination Rooms(1) Two or more areas may be considered as a combination room if the opening between the areas occupies the larger of 3 m² or 40% or more of the wall measured on the side of the dependent area. (2) Where the dependent area is a bedroom, direct passage shall be provided between the two areas. (3) The opening required…).

Hallways and doors

Hallways within a dwelling unit must be at least 860 mm wide. They may be 710 mm where only bedrooms and bathrooms are at the far end and a second exit is provided in the hallway or in each bedroom (9.5.4.1.OBC Div. B 9.5.4.1. Hallway Width(1) The unobstructed width of a hallway within a dwelling unit shall be not less than 860 mm, except that the hallway width is permitted to be 710 mm where (a) there are only bedrooms and bathrooms at the end of the hallway furthest from the living area, and (b) a second exit is provided (i) in the hallway near the…). Minimum door sizes are in Table 9.5.5.1; for example, the required entrance door to a dwelling unit is at least 810 mm wide and 1,980 mm high (Table 9.5.5.1.OBC Div. B Table 9.5.5.1. Minimum Door Sizes — Forming Part of Sentence 9.5.5.1.(1)Table 9.5.5.1 — Minimum Door Sizes — Forming Part of Sentence 9.5.5.1.(1) At Entrance to: | Minimum Width, mm | Minimum Height, mm Dwelling unit or house with a secondary suite including common spaces (required entrance) Vestibule or entrance hall | 810 | 1,980 Stairs to a floor level that contains a finished space…).

Existing houses and basements

Part 11 applies to buildings that have existed for at least five years (Div. A 1.3.3.3B.OBC Div. A 1.3.3.3B. Application of Part 11(1) Except as provided in Sentence (2), Part 11 of Division B applies to the design and construction of existing buildings, or parts of existing buildings, that have been in existence for at least five years. (2) If a building has been in existence for at least five years but includes an addition that has been in…). Table 11.5.1.1.-C offers a compliance alternative for room heights in existing dwelling units other than secondary suites: lower minimums over the required area and the path of egress (Table 11.5.1.1.-COBC Div. B Table 11.5.1.1-C. Compliance Alternatives for Residential Occupancies — Forming Part of Article 11.5.1.1.Table 11.5.1.1.-C Compliance Alternatives for Residential Occupancies — Forming Part of Article 11.5.1.1. C.A. Number | Division B Requirements | Compliance Alternative C1 | 3.1.4.7. | Existing heavy timber construction acceptable where construction is within 90% of member sizes listed in Part 3. C2 | 3.1.5.2. to…, 11.5.1.1.OBC Div. B 11.5.1.1. Compliance Alternatives(1) A compliance alternative shown in Table 11.5.1.1.-A, 11.5.1.1.-B, 11.5.1.1.-C, 11.5.1.1.-D/E or 11.5.1.1.-F may be substituted for a requirement contained in Part 3, 4, 6 or 8 where the chief building official is satisfied that compliance with the requirement is impracticable because, (a) of structural or…). If you are finishing an older basement with low beams, ask your building department whether it applies.

Common mistakes

  1. Measuring to the joists instead of to the finished ceiling and floor.
  2. Counting closet area toward the 7 m² or 9.8 m² bedroom minimum.
  3. Forgetting the 1,400 mm rule under sloped attic ceilings.
  4. Bulkheads that drop the clear height below 1,950 mm (or 1.85 m in a suite).
  5. Calling a room a bedroom without also meeting the egress window and smoke alarm rules.

How to look it up yourself

In Division B, Part 9 of the 2024 Compendium, Section 9.5 is "Design of Areas, Spaces and Doorways". Search for "Room Ceiling Heights", "Areas of Bedrooms", "Areas of Master Bedrooms" (the code's own heading), "Kitchen Areas" and "Hallway Width". Ontario's room area articles carry letters, such as 9.5.3A. to 9.5.3F., so type the number exactly.

Rooms and spaces (Section 9.5) are on the House exam syllabus. Read the free House exam study guide and take the free practice quiz on that page.

Based on the official 2024 Building Code Compendium on ontario.ca.

© King's Printer for Ontario, 2024. Reproduced with permission.

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Frequently asked questions

What is the minimum ceiling height in Ontario?
For living rooms, dining rooms and kitchens, 2,300 mm over at least 75% of the required floor area, with at least 2,100 mm clear at any point over the required area. Halls and other finished rooms need 2,100 mm (Division B, Table 9.5.3.1.).
What is the minimum basement ceiling height in Ontario?
2,100 mm over at least 75% of the basement area, reduced to 1,950 mm under beams and ducts. In a secondary suite, the ceiling must be at least 1.95 m and at least 1.85 m under beams and ducting (Division B, Article 9.5.3.1. and Table 9.5.3.1.).
What is the minimum bedroom size in Ontario?
7 m2 without built-in cabinets or 6 m2 with them. At least one bedroom in each dwelling unit must be 9.8 m2, or 8.8 m2 with built-in cabinets (Division B, Articles 9.5.3D.1. and 9.5.3D.2.). Closets are not counted unless stated.
What ceiling height does a bedroom need?
2,300 mm over at least 50% of the required area, or 2,100 mm over all of it. Floor areas with less than 1,400 mm of clear height do not count toward the required area (Division B, Table 9.5.3.1.).
How wide must a hallway be in a house?
At least 860 mm, or 710 mm in some cases where only bedrooms and bathrooms are at the far end and a second exit is provided (Division B, Article 9.5.4.1.).