Cook County Code Chapter 102 zoning limits floor area, lot coverage, and setbacks in unincorporated residential districts, while many suburban Cook municipalities have adopted mansionization rules capping FAR and bulk for teardowns in established neighborhoods.
In unincorporated Cook, Chapter 102 sets maximum lot coverage (typically 25 to 30 percent), height limits of 35 feet, and front, side, and rear setbacks scaled by district. There is no explicit countywide FAR cap, but bulk plane and side-yard rules constrain massing. Suburbs including Wilmette, Winnetka, Glencoe, Evanston, Oak Park, and Park Ridge have adopted explicit FAR limits (often 0.4 to 0.5), tear-down review, and side-yard setbacks tied to lot width to slow mansionization. Variances require Zoning Board of Appeals review with neighbor notice and findings of hardship.
Building beyond approved FAR, lot coverage, or setbacks triggers stop-work orders, denial of certificate of occupancy, and required removal or reduction of nonconforming structures, plus daily fines under the local zoning code.
See how Arlington Heights's anti-mansionization rules stack up against other locations.
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