How big can a detached garage be in Troy?

Troy caps the combined ground floor area of all detached accessory buildings at 450 sq ft plus 2% of the lot area (Section 7.03.B.2.c). The result can never exceed the home's ground-floor footprint or 600 sq ft, whichever is greater.

Worked example for a 12,000 sq ft lot:

• Formula: 450 + (2% of 12,000) = 450 + 240 = 690 sq ft.
• Ceiling: the greater of the home's ground-floor footprint or 600 sq ft. With a 1,200 sq ft footprint, the ceiling is 1,200 sq ft.
• Result: up to 690 sq ft of detached accessory building area.

Two other caps apply. The buildings may not cover more than 25% of the required rear yard (Section 7.03.B.2.b), and height is limited to one story and 14 ft (Section 7.03.B.2.d). Confirm the numbers for your lot with the Planning Department at 248-524-3364.