Open Space Ratio
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%.
Popular Real Estate Terms
Are you planning on buying a house? If you are, you’re going to love the Buyer's Market definition. But if you are a home seller, you will wish that term never comes up again in your ...
Process of the borrower giving the lender security to obtain the loan. ...
Statutes stipulating that the property of deceased individuals is distributed in a way that assumes that property during marriage is jointly owned and equally shared by the spouses ...
An interim or provisional court decree, which is not final and can be reversed or amended, normally issued to direct additional proceedings prior to issuing a final decree. For example, an ...
Classification of one's ownership rights in land. One way either buy the land and own all rights to it or lease it where one's rights are described in and limited by the lease agreement. ...
Time interval between buying a real estate investment and selling it. A sound way to determine the return from a real estate investment is over its life. For example, if land was bought on ...
Expenditures incurred to initially purchase property, including incidental costs necessary to put the property into existing use and location. This cost is then depreciated over the assets ...
Also called the Rule of the Sum of the Digits. An approach that bank use to formulate a loan amortization schedule. It results in a borrower paying more interest in the beginning of a ...
Document evidencing the passage of title to a purchaser of property sold for taxes. The tax deed is issued upon foreclosure of the property lien. Typically, there is a grace time period ...

Have a question or comment?
We're here to help.