How Big Can a Detached Garage Be?

When planning to build or purchase a home with a detached garage, one of the most pressing questions is how big can it be. The answer, however, is not straightforward and involves multiple factors, primarily your local building codes.

Factors Influencing Garage Size

The size of a detached garage is not only determined by the available square footage of your property but also by local building regulations. In most cases, there are detailed guidelines that specify how much of the property can be covered by building structures, including detached garages.

Percentage of Property Area

Many counties limit the total square footage that can be constructed to a percentage of the total property area. For instance, a common restriction is that the sum of the living area and detached structures cannot exceed a certain percentage of the total land area. This percentage can range from 25% to 50%, depending on local zoning laws. If your property is relatively small, this restriction can significantly limit the size of any detached structures, including garages.

Rural Areas with Septic Systems

In rural settings without access to municipal sewer lines, construction regulations often require that the size of detached structures, especially those involving parking spaces, are kept to a minimum. This is to ensure that the underground septic system remains undisturbed. You must maintain sufficient distance from the septic tank and avoid driving on leech lines, which are crucial components of the septic system responsible for distributing waste properly.

Real-World Example

Let’s illustrate this with a concrete example. A few years ago, I was considering purchasing a 1300 sq ft ranch home on a full acre of land. The property came with an attached structure described as a "6-car detached garage". This garage was exceptionally large, consisting of one massive interior with three double-wide 2-car bays plus a spacious storage area at one end. It was clearly designed for workshop use, with many professionally installed electrical outlets and a high-quality electrical panel. Despite the vast size, it was about the same size as the house itself, highlighting that local codes play a crucial role in limiting the size of such detached structures.

RV Storage

It's worth noting that detached garages can vary in size depending on their intended use. For example, some garages can accommodate two RVs, demonstrating the flexibility and potential for larger structures under certain conditions.

Legal Considerations

While local building codes provide a framework, specific laws can vary significantly from one region to another. Therefore, it is essential to consult with your local building code department or hire an architect or a contractor who is well-versed in local regulations. Ignoring these guidelines can result in major legal and financial repercussions.

Importance of Reading Local Laws

It's crucial to read and understand the applicable laws in your area. As highlighted in the comments from other users, failing to do so can lead to significant issues. This includes ensuring that your detached garage does not interfere with underground septic systems or exceed the allowable square footage for permanent structures on your property.

The size of a detached garage is a critical aspect of property planning. By adhering to local building codes and understanding the limitations imposed by your local area, you can ensure that any future construction or renovation project is compliant and successful.