When constructing an apartment building, it is important to understand the Building Standards Act in advance. Knowing whether a condominium can be built on your land and the maximum scale permissible will allow you to proceed with your plans smoothly.
This article provides a detailed explanation of the conditions for building a condominium, as well as non-compliant buildings and existing non-conforming properties, based on the characteristics of the Building Standards Act.
What Kind of Law Is the Building Standards Act?
The Building Standards Act is a law that consolidates the rules to be observed during the construction and use of buildings, so that people can live safely and securely. Standards are established for a building's purpose, site, facilities, and structure.
Characteristics of the Building Standards Act
The Building Standards Act stipulates the types of structures that may be built, as well as upper limits on floor area and building area. Prior to construction, legal compliance is reviewed through a "building confirmation," and work cannot begin without receiving a confirmation certificate. Intermediate inspections during construction and final inspections upon completion are also required.
Difference Between Individual Regulations and Collective Regulations
Individual regulations are safety standards for the building itself (structural durability, earthquake resistance, lighting, ventilation, etc.) and apply uniformly nationwide. Collective regulations are standards aimed at improving the environment of an area (site, roads, building coverage ratio, floor-area ratio, height restrictions, etc.) and apply primarily within city planning areas and quasi-city planning areas.
How Are Condominiums Classified Under the Building Standards Act?
Condominiums are classified as "collective housing" under the Building Standards Act and are further treated as "special buildings." They are subject to stricter conditions than ordinary residences.
What Is Collective Housing?
When a single structure contains two or more dwelling units along with shared staircases, hallways, or an entrance, it is classified as collective housing.
What Are Special Buildings?
Buildings frequented by an unspecified number of people and posing a fire risk qualify as special buildings. Condominiums are treated the same as schools, hospitals, and department stores, making the construction conditions more stringent.
What Are the Conditions for Building a Condominium?
The Building Standards Act sets out many rules regarding condominium construction. Let us look at the main conditions.
Building Coverage Ratio and Floor-Area Ratio
A higher building coverage ratio allows for a larger structure, while a higher floor-area ratio allows for taller construction. The upper limits vary depending on the land and zoning district.
Building Height Restrictions
There are four types of height restrictions—absolute height limits, road setback line limits, north setback line limits, and shadow regulations—and their application varies depending on the zoning district.
- Absolute height limit: Up to 10m or 12m in Category 1 and Category 2 low-rise exclusive residential zones
- Road setback line limit: Slope restrictions to secure sunlight and ventilation along fronting roads
- North setback line limit: Height restrictions to secure sunlight for the neighboring property to the north
- Shadow regulations: Time restrictions on shadows cast by mid- to high-rise structures
Road Frontage Requirements
The site must have at least 2m of frontage on a road with a width of 4m or more. If the width is insufficient, construction may become possible through a "setback."
Installation of Disaster Prevention Equipment
For condominiums of three stories or more, installation of evacuation facilities, fire hydrants, sprinklers (11 floors and above), smoke exhaust equipment, emergency lighting, evacuation routes, lightning rods (20m or higher), and emergency elevators (over 31m) is required.
Floor Plan and Interior Restrictions
Flame-retardant or quasi-non-combustible materials are required for wall and ceiling finishes, and rooms without windows must have fire-resistant construction.
Lighting, Ventilation, and Sound Insulation
Window area must be at least 1/7 of the habitable room's floor area, and ventilation openings must be at least 1/20. Sound-insulating walls that consider the noise of neighboring residents are also required.
Periodic Reporting Obligation
Condominiums are required to submit a periodic report once every three years. Failure to report may result in a fine of up to 1,000,000 yen.
How Are Areas Where Condominiums Can or Cannot Be Built Determined?
Condominiums are built within city planning areas and generally cannot be built outside them. Restrictions also apply depending on the zoning district.
Structure of City Planning Areas
City planning areas are divided into urbanization promotion areas, urbanization control areas, and undesignated areas, and condominiums are primarily built within urbanization promotion areas.
Relationship with Zoning Districts
Building coverage ratios, floor-area ratios, and height restrictions are specified for each of the 13 types of zoning districts. In exclusive industrial zones, condominiums generally cannot be built.
Checking Municipal Ordinances Is Also Necessary
Some municipalities have their own ordinances, so be sure to check in advance.
What Is the Difference Between Non-Compliant Buildings and Existing Non-Conforming Properties?
There are two types of problem properties related to the Building Standards Act: "non-compliant buildings" and "existing non-conforming properties." It is important to accurately understand the difference between the two.
Characteristics of Non-Compliant Buildings
A building qualifies as non-compliant if it was constructed without a building confirmation application or if it differs from the submitted application. Common cases include the following.
- Unauthorized construction or buildings that differ from the application content
- Exceeding the building coverage ratio or floor-area ratio due to partial sale of the site after construction
- Unauthorized extensions, renovations, or changes of use
Characteristics of Existing Non-Conforming Properties
These are properties that were legally compliant at the time of construction but no longer conform to current standards due to legislative amendments. Continuing to live in or use them as-is is not a problem, but conformance to current law is required at the time of any extension or renovation. Applicable cases include changes to zoning districts, revisions to building coverage ratios and floor-area ratios, and buildings constructed before the new earthquake resistance standards.
What Are the Key Points for Avoiding Investment in Non-Compliant Buildings?
To avoid non-compliant buildings in real estate investment, the following checks are essential.
Checking the Building Confirmation Application and Inspection Certificate
The building confirmation application allows you to verify legal compliance of the design, while the inspection certificate confirms that there are no issues after construction.
Checking the Status of Fire Inspections
If the legally mandated annual building equipment inspection and the special building periodic survey report every three years are being properly conducted, it is evidence that the property complies with the Building Standards Act.
What Should You Watch Out for When Purchasing an Existing Non-Conforming Condominium?
While existing non-conforming properties are often in prime locations, you need to understand the following risks.
- Restrictions on extensions, renovations, and rebuilding: Extensions or renovations at the current scale may not be possible
- Low asset value: The building is old and maintenance costs may increase
- Difficulty securing financing: Obtaining funding may be more difficult than for other condominiums
- Difficulty selling: The property may be deemed to have low asset value, making it hard to find a buyer
Frequently Asked Questions (FAQ)
Q. What is "building confirmation" under the Building Standards Act?
It is a system for reviewing whether a building complies with the law. Once compliance is recognized, a confirmation certificate is issued and construction can begin.
Q. What is the biggest difference between a non-compliant building and an existing non-conforming property?
A non-compliant building has violated laws and regulations from the time of construction, while an existing non-conforming property was legally compliant at the time of construction but no longer meets the standards due to legislative amendments.
Q. Can an existing non-conforming property be extended or renovated?
It is possible, but the extended or renovated portions must conform to the current Building Standards Act. Depending on the scale, rebuilding may be required in some cases.
Q. Are there zoning districts where condominiums cannot be built?
Condominiums generally cannot be built in exclusive industrial zones. Construction is also basically restricted in urbanization control areas.
