What is the Size of a 1 Bedroom Apartment, Duplex or House
A one-bedroom apartment or house is suitable for single occupants but it can also accommodate two people especially couples sharing the same bed. One-bedroom dwellings come in all types of architectural designs – duplex, detached house and apartments. Apartments are the most common design for single occupancy in highly populated countries with a shortage of land due to the need for saving space. As an example, it’s more economical and efficient to have an apartment block with 100 units rather than 100 individual detached homes.
What is the difference between a 1-bedroom apartment and self-contained apartment?
Apartments are known as Flats in the United Kingdom and other British Commonwealth countries. A 1-bedroom apartment has a private bedroom separated from other rooms by an internal wall, whereas a self-contained flat (also known as a studio apartment) has an open-plan bedroom, kitchen and living room [See Drawings D1 and D2 Below for Illustration] An open plan layout has one huge living area with no internal wall divisions between the sleeping, dining and kitchen areas. The only room that is enclosed for privacy purposes is the bathroom/toilet.
The smallest dwelling that you can have in a decent housing development is a self-contained apartment, which is basically a single room. A one-bedroom apartment is often larger than a self-contained flat.
To save space, single occupancy dwellings in MDU blocks cannot accommodate an ensuite bathroom or toilet. Instead, a common bathroom/toilet with direct access from the living room is built, so that visitors can use the toilet as well.
Minimum Room Requirements (IRC Specifications)
The size of an apartment should comply with building codes. According to the International Residential Code (IRC) 2015, the minimum area of a habitable room should be at least 70ft2 or 6.5m2 with the exception of kitchens. The floor perimeter is regulated as well, the minimum horizontal length and width of a habitable room is 7 feet (2134mm), and once again kitchens are exempt from this rule. The minimum floor to ceiling height of a room is 7ft (2134mm) with cellars and basements being exempt from this rule. The minimum height of bathrooms, toilet and laundry rooms is 6.67 feet (2032mm).
Before 2015, the IRC allowed a minimum floor area of 120 ft2 (11.15m2) for one habitable room in the house, and a minimum area of 70 ft2 in other rooms. The 120 ft2 requirement was removed, and replaced with 70 ft2.
IRC vs USA Local Authority Codes
IRC codes are not necessarily applied in all countries including the United States. They are an international architectural guideline and standard. It’s up to the national housing authorities to adopt them. In the USA, the IRC standards are used in 49 states but the codes are often modified and altered by local authorities. The United States has building codes which vary by state, city and county. Consistency is lacking across the country as a result. Below is an example of how Building Codes have evolved in the USA over the years since 1929 and these are some of the minimum room dimensions specified in Section 27-2074 (Article 4 Minimum Room Sizes and Occupancy Regulations Page 66) Housing Maintenance Code of New York City.
Living room in apartments – minimum floor area 132 ft2/12.26m2 (MDU built 18 April 1929 to 9 December 1955)
Living room in apartments – minimum floor area 150 ft2/13.94m2 (MDU built after 9 December 1955)
Every other living room – minimum floor area 80 ft2/7.4m2 (MDU built after 18 April 1929)
Every other living room – minimum length of each side 8 feet/2438mm (MDU built after 18 April 1929)
Minimum height of living room – 8 feet/2438mm (MDU built after 18 April 1929) Basements and cellars are exempted.
Exemptions apply to kitchens, rooms in Class-B MDUs, rooms in lodgings and other special cases stated in Section 27-2074.
The minimum floor area of a Class-B MDU room is 60 ft2 (5.57m2) and room length of at least 6 feet (1829mm).
The above requirements are prescribed by the City of New York. Other states may have their own codes and regulations which are more or less different from the above. As you can see, the minimum requirements for the City of New York are quite different from the IRC specifications.
What is the Minimum Size of a 1-Bedroom Apartment?
To find out the size of a one-bedroom apartment you have to add up the minimum sizes of all rooms or floors in your design plan. Room sizes can be increased based on minimum requirements required by Building Codes. The calculations are shown below:
The total gross floor area (GFA) of a single occupancy dwelling can determined as follows:
Our design should be guided by building codes in our area (city or county). IRC standards will be assumed in this case. According to IRC, the smallest habitable room we can build is 70 ft2. Kitchens, bathrooms and passageways are an exception. IRC specifies a minimum size of 30 x 60 inches for an enclosed toilet room.
The minimum size of a bathroom is based on minimum clearances (distance) from other sanitary installations such as the bathtub, water closet and wash-hand/lavatory basin:
Minimum clearance between the centreline of a water closet and edge of bathtub – 15 inches.
Minimum clearance between the front face of toilet bowl and edge of bathtub – 21 inches.
Minimum clearance between the centreline of a water closet and face of wall – 15 inches.
Minimum clearance in front of the water closet measured from the front edge of the toilet bowl – 21 inches.
Minimum clearance in front of the lavatory basin measured from the front edge of the toilet bowl – 21 inches.
Minimum size of shower cubicle – 30 x 30 inches.
Minimum clearance between the outer face of shower cubicle and door opening – 24 inches.
Decide what kind of bathroom you are going to have. Are you going to have an open-plan bathroom whereby the water closet, shower and bathtub are combined or do you prefer a separate toilet and bath? If you have limited space, a combined bath and toilet is the best option, and in this case a shower cubicle will take less space than a bathtub.
The minimum size of a combined bath (shower) and toilet is calculated as follows:
L1 = C1 + C2 + S, where L1 is the room length (side 1), C1 = minimum clearance of water closet centreline from wall, C2 = minimum clearance of water closet centreline from shower cubicle, S = minimum shower width.
L1 = 15 + 15 + 30 = 60 inches.
L2 = T + C3 + B, where L2 is the room length (side 2), T = length of water closet, C3 = minimum clearance measured from front edge of toilet bowl, and B = width of lavatory basin.
L2 = 29 + 21 + 18 = 68 inches.
The minimum size of this combined bath and toilet is 68 x 60 inches (5.67 x 5 feet) = 4080 square inches (28.35 ft2).
Bedroom – 7 x 10 feet
Living room – 7 x 10 feet
Combined bath and toilet – 5.67 x 5 feet
Kitchen – This is part of the open plan area. Let’s make it half the length of the living room. The overall width of the apartment is 14 inches, subtracting the bath (14 – 5.67 = 8.33 ft). So the size of the kitchen is – 5 x 8.33 feet.
Total area = 70+70+28.35+41.65 = 210 ft2
Based on minimum requirements, the minimum internal size of a 1-bedroom apartment is 210 ft2 (19.5m2).
What is the Minimum Size of a Self-Contained Apartment?
The minimum size of a self-contained apartment should be proportionally smaller than a 1-bedroom apartment. Using minimum requirements, the net floor area can be calculated as follows:
Living room – 7 x 10 feet
Combined bath and toilet – 5.67 x 5 feet
Kitchen area – This is part of the open plan area. The overall internal length of the apartment is (7+5.67=12.67 ft), and its overall internal width is 10 feet + Allowance for kitchen area (10%) = 11 feet.
Sleeping area – This is part of the open plan area. We can further increase the apartment width by adding a 10% allowance for sleeping area, and the length can be increased as well by the same percentage, but we shall keep to the minimums.
Total area = 12.67 x 11 = 139.37 ft2
Based on minimum requirements, the minimum internal size of a self-contained apartment is 139.4 ft2 (12.95m2).
Size of 1-Bedroom Apartments in the Property Market
Obviously, one-bedroom apartments in the property market are much larger than the minimum size based on IRC minimum requirements for habitable rooms.
Size of One Bedroom Apartments in the USA (Chicago, New York and Los Angeles)
In the USA, the size of one-bedroom apartments ranges from 525 ft2 to 1053 ft2 (49m2 to 98m2). The common size of studio apartments is 375 ft2 to 593 ft2 (35m2 to 55m2). The lower outlier can be as small as 170 to 226 ft2 (16m2 to 21m2) and the upper outlier is 700 to 764 ft2 (65m2 to 71m2).
Size of One Bedroom Apartments in the United Kingdom (England)
In England, the size of one-bedroom apartments ranges from 333 ft2 to 745 ft2 (31m2 to 69 ft2). Studio apartments are smaller, ranging in size from 125 ft2 to 448 ft2 (12m2 to 42 m2).
Size of One Bedroom Apartments in China
The common size of one-bedroom apartments in China is 334 ft2 to 1076 ft2 (31m2 to 100m2).
Apartments in the USA are way bigger than those in England and China. Apartments in England and China are more or less the same size, but China has more land than England. This scenario can be explained by the population density in each of these countries. The United States has a smaller population density at 36 people per square kilometre, so it follows that they have more space (land) to build much bigger homes than England and China. England has a higher population density at 281 people per square kilometre, followed by China at 153 people per square kilometre. People in China have more space to build much bigger homes than England.
USA – 36 per km2 (94 per m2)
China – 153 per km2 (397 per m2)
England – 281 per km2 (727 per m2)