Adding a garage attached or detached is one of the more involved residential permit projects. The site plan requirements are more detailed than a simple fence or shed permit, and the setback rules differ depending on whether the garage is attached to the house or a separate structure.
I’m Engineer Wasim. This guide walks through what a garage addition site plan must include and the key variables that affect permit approval.
Attached vs. Detached Garage Why It Matters for Site Plans
Attached garage
connected to the main house. Treated as part of the principal structure. Setbacks apply the same way as the house: typically 25 ft front, 20 ft rear, 7.5 ft side for most residential zones.
Detached garage
a separate structure. Treated as an accessory structure. Setback requirements are typically reduced: often 5 to 7.5 ft rear and side. Front yard placement is usually prohibited.
This distinction changes how setbacks are calculated and labeled on the site plan. Using the wrong setback standard is a common rejection cause.
What a Garage Site Plan Must Include
- Property boundaries with dimensions
- Existing house with dimensions and all setbacks
- Proposed garage with dimensions and all setbacks from property lines
- Whether attached or detached clearly labeled
- Driveway connection — show how the garage connects to the driveway and street access
- Impervious surface calculation — garage footprint + any new driveway area adds to coverage
- Distance between detached garage and house if detached (typically 10 ft minimum fire separation)
- North arrow, scale, title block
Common Garage Permit Site Plan Issues
Wrong setback category applied.
Detached garages use accessory setbacks, not principal structure setbacks. If you apply the 25 ft front setback to a detached garage that only needs 10 ft, you may conclude it’s non-compliant when it isn’t.
Impervious surface not calculated.
A new two-car garage slab plus expanded driveway can add significant hard surface. Calculate the total before submitting.
Driveway connection missing.
The reviewer wants to see how vehicles access the garage from the street.
PE stamp for structural work.
If the garage has a second-story living space, or if the foundation work is unusual, a PE stamp may be required.
For Florida Garage Permits
In HVHZ zones (Miami-Dade and Broward), garage structures require product approval (Miami-Dade NOA) for all components. The site plan and structural drawings must reflect HVHZ wind speed requirements.
For all Florida garage addition permits, visit Site Plans FL.
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