Minimum Height and Size Standards for Rooms in Buildings

Minimum heights and size standards for rooms ensures that there is good ventilation, lights and comfortable living inside the room. Height and size standards for rooms varies from one country to another and is mostly based on the preference of clients to meet their demand.

However, in the absence of controls, developers (both public and private sector) tend to reduce the size of dwellings being developed whilst trying to avoid any reduction in value. Added to that, established minimum height and size standards allows disciplined and systematic growth of buildings and towns, and provide proper utilization of space.

Table of Contents

• Height Regulation for Rooms
  • 1. Habitable Rooms
  • 2. Bedroom Height Restrictions
  • 3. Bathrooms, water closets and stores
  • 4. Kitchen
  • 5. Ledge
  • 6. Hallways
• Minimum Standard Sizes of Rooms
  • 1. Habitable Rooms
  • 2. Dining room
  • 3. Primary Bedrooms
  • 4. Secondary Bedrooms
  • 5. Kitchen
  • 6. Bathrooms and water closets
  • 7. Ledge
  • 8. Hallways
  • 9. Mezzanine floor

Height Regulation for Rooms

1. Habitable Rooms

• The minimum height from the surface of the floor to the ceiling or bottom of slab should be not less than 2.75m.
• For air-conditioned rooms, a height of not less than 2.4 m measured from the top of the floor to the lowest point of the air-conditioning duct or the false ceiling should be provided.
• According to Ontario Building Code (OBC), 2.3 m over at least 75% of the required floor area with a clear height of at least 2.1 m at any point over the required area

2. Bedroom Height Restrictions

• As per OBC, the bedroom height should be 2.3 m over at least 50% of the required floor area.
• Alternatively, 2.1 m over 100% of the required floor area
• Any part of the floor area having a height of less than 1.4 m shall not count when calculating required floor area

3. Bathrooms, water closets and stores

• The height of all such rooms measured from the floor in the ceiling should not be less than 2.4m.
• In the case of a passage under the landing, the minimum headway may be kept as 2.2m.
• According to OBC, bathroom minimum height of 2.1 m in any area where a person would be in a standing position

4. Kitchen

• The height of the kitchen measured from the floor to the lowest point in the ceiling should not be less than 2.75m except for the portion to accommodate floor trap of the floor.
• However, according to OBC, kitchen height should be 2.3 m over at least 75% of the required floor area with a clear height of at least 2.1 m at any point over the required area.

5. Ledge

It shall have a minimum head room of 2.2m.

6. Hallways

Minimum height should be 2.1 m

Fig.1: Height of Rooms

Minimum Standard Sizes of Rooms

1. Habitable Rooms

• The area of habitable rooms should not be less than 9.5m2 where there is only one room. However, such rooms shall have at least 13.5m2 of floor area and no dimension less than 3.0 m as per Ontario Building Code (OBC).
• Where there are two rooms, one of these should not be less than 9.5 m2 and other be not less than 7.5 m2 with a minimum width of 2.4m.
• Natural ventilation shall be provided.

2. Dining room

• It should have a floor area not less than 9.5m2 with a minimum width of 2.4m.
• According to OBC, dining room shall have at least 3.25 m2 of floor space when combined with other rooms, and at least 7.0m2 of area when not combined.
• minimum dimension of 2.3 m.
• Dining rooms vary greatly in size. It should be ensured that furniture is accommodated.
• Natural ventilation shall be provided.
  
  Fig. 2: Dining Room

3. Primary Bedrooms

• One bedroom shall have at least 9.8m2of floor area
• Minimum dimension should be 2.7 m
• Natural ventilation must be provided

4. Secondary Bedrooms

• It shall have at least 7m2 of floor area
• Minimum dimension is 2.0 m

5. Kitchen

• Minimum floor area required is not less than 5.5 m2. But OBC specify that kitchen room shall have at least 4.2m2 of floor area
• It should not be less than 1.8min width at any part. With a separate storeroom, the area may be reduced to 4.5m2.
• Mechanical ventilation must be provided (exhaust fan).
• Ensure that appliances can all open without interfering with one another, and that standing space is provided.
  
  Fig. 3: Mechanical appliances in kitchen room

6. Bathrooms and water closets

1. The size of bathroom should not be less than 1.5m x 1.2m or 1.8 m2.
2. If it is combined with water closet, its floor area should not be less than 2.8 m2.
3. the minimum floor area of a water closet should be 1.1 m2.

7. Ledge

1. A ledge in a habitable room shall not cover more than 25% of the floor area of the floor on which it is constructed
2. It should not interfere with the ventilation of the room under any circumstances.

8. Hallways

Hallways shall have a width of at least 860 mm except where the overall width of the building is less than 4.3 m, and this may be reduced to 710 mm

9. Mezzanine floor

The minimum size of a mezzanine floor, if it is used as a living room, should not be less than 9.5m2.