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
Property owned and held jointly and equally shared by each spouse. It is purchased during their marriage, regardless of the wage-earning situation of either spouse. A spouse may not make a ...
The term comparables is used to better determine the value an asset has when compared to others, similar to it. Real estate comparables are used in assessments to determine a house’s ...
The cost of property, such as a home owned for tax purposes. For example, a home was purchased for $150,000. capital improvements to it cost $15,000. The house was later sold for $230,000. ...
Tenancy that may be terminated by one party- the tenant or the landlord- at any time. The agreement may be in writing or oral. For example, Jack has an oral agreement to use Christine's ...
Highest amount a property is worth equal to the amount that would have to be paid to buy equivalent property in the market place. ...
Loan with a significant down payment with the balance being paid in equal periodic payments over a short time period. There is no interest charge. An example is when a seller of real ...
Descriptive of a property boundary that follows the course of a river or estuary. For example, a land description may say its boundary follows "the meander of the river" meaning the ...
Certificate issued by the government showing evidence that the veteran is qualified and the amount of guarantee available to maintain a VA loan. It is one of the documents necessary to ...
Buyer agrees to accept the responsibility for the existing mortgage. The seller is not relieved of the obligation unless the lender agrees to release it. Many lenders charge points and ...

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