One-story detached structures that are used as tool and storage sheds, playhouses or similar uses that do not exceed 256 square feet and are not classified for occupancy do not require a permit.

The exemption does not apply to any other relevant permitting, such as electrical, plumbing, or mechanical work. The exemption also does not apply for other required permits, such as zoning, land disturbance, flood hazard area, etc.

Construction documents are required to be submitted to and reviewed by the Building Official except when no permit is required or when the Building Official determines the work is of a minor nature. Basic drawings showing a dimensioned floor plan, elevations, framing plans indicating structural member sizes and on center spacing and a foundation plan with anchorage details will generally suffice. Plans for prefabricated metal carports, metal garages and similar structures that are not designed prescriptively in accordance with the USBC, may be required to
be sealed by a registered design professional and may require additional engineered details

In general, footings for carports, garages and sheds are to be constructed with the the same requirements as any other structure. The code does not require footings for structures that are exempt from the permit requirement and meet the below criteria: 

• The building eave height is 10 feet or less
• The maximum height from the finished floor level to grade does not exceed 18 inches
• The supporting structural elements in direct contact with the ground are placed level on firm soil and when such elements are wood they are approved pressure preservative treated suitable for ground contact use
• The structure is anchored to withstand wind loads in accordance with the code, and the structure is of light-frame construction with vertical and horizontal structural elements primarily formed by a system of repetitive wood or light gauge steel framing members, with walls and roof of light weight material, not slate, tile, brick or masonry.

In general, the bottom of footings for structures are required to be below the local frost depth.

Regardless of the size, type of structure, or exemption from application for permit, anchoring of accessory structures is required by Code and extremely important. For sheds that meet the exception criteria described above and are anchored directly to the ground, auger type or strap type anchors installed in accordance with the manufacturer’s installation instructions are generally acceptable.