Definition of "Open space ratio"

Gena Taylor real estate agent

Written by

Gena Taylorelite badge icon

Coldwell Banker FI Grey & Son Residential Inc.

When talking about the open space ratio we are referring to a term that is used in zoning laws and regulations. The open space ratio is a term used to measure open space on a developed land or zoning lot. The open space ratio is calculated in the percentage of open space in the building's square footage. For example, a housing subdivision containing 100 acres has devoted 10 acres to open space. Therefore, the open space ratio is 1/10 or 10 percent (10/100). Or an office building of 10,000 square feet with an open space ratio of 20% will have 2,000 square feet designated to remain open space.

Open Space Ratio in Residential Real Estate

The term open space ratio is a concept that applies to residential developments, and it usually refers to commonly used open space. While not necessarily a way to determine the ratio of “green” open space on lots of land proposed for residential development. The term open space ratio can refer to two types of open space:

  • Allowable Areas

Allowable open space are the areas that are required common areas to be maintained and remain undeveloped for the benefit of those living or working on the lot parcel: parking lots, yard requirements, floodplains, recreational areas, stormwater management systems, etc.

  • Prohibited Areas

Prohibited open space areas are privately owned sites that are not accessible for those living or working on the lot parcel and that are also available for further structural developments.

How is Open Space Ratio Calculated?

The open space ratio is a zoning law used by municipalities to be able to control the types of buildings built, their height, and their ratio of open space. It is a means for municipalities to ensure that the open space available on a developed land makes up a certain percentage of the lot developed. In most cases, that requirement is of a 20% open space ratio.

Open Space Ratio Formula:

Open Space Ratio (OSR) = Commonly-owned Open Space / Total Area Proposed for Development


So if you have 12 acres available for residential development and you have 6 acres of commonly-owned open space (ponds, recreation area, parking area, buffers, etc) you will have an open space ratio of 50%.

image of a real estate dictionary page

Have a question or comment?

We're here to help.

*** Your email address will remain confidential.
 

 

Popular Real Estate Terms

In real estate, the term "preamble" refers to an introductory statement that outlines the fundamental principles and goals guiding the industry's practices. Specifically, in the National ...

Transfer of both real and personal property. An example is the sale of a home with personal belongings. Putting together a group of property to be sold together, perhaps at a discount ...

Absence of a personal liability such as when a creditor may seize an office building used as security for the obligation but cannot attach any other assets of the debtor. ...

Same as term nonconforming use: Property use which is in violation of the current zoning ordinance, but had been in use prior to the zoning ordinance's enactment. A nonconforming use is ...

Provision in a lease agreement allowing the landlord to raise the rental to take into account inflation, higher upkeep costs, and higher interest rates. An index may be used such as the ...

To understand what a principal broker is, we have to go back up the family tree of real estate.You do understand all brokers can be real estate agents, but not every real estate agent can ...

An agreement specified in the lease providing the tenant the option to renew the lease for a given time period upon the expiration of the initial lease. Most lease options include the ...

Siding made out of aluminum, plastic derivates, or cement asbestos having ridges and valleys which is attached to the sides of buildings. ...

Corporation whose stockholders are taxed as partners. That is, income is taxed as direct income to the shareholders. The key advantage of this tax treatment is that shareholders escape ...

Popular Real Estate Questions