'Granny flats' proposal moves forward as Chicago council reaches compromiseThe proposal to allow all Chicago neighborhoods the ability to build coach housesbasement, attic and garage units. The proposal to allow all Chicago neighborhoods the ability to build coach housesbasement, attic and garage units. The proposal to allow all Chicago neighborhoods the ability to build coach housesbasement, attic and garage units. CHICAGO (WLS) -- A proposal to allow all Chicago neighborhoods the ability to build coach houses, basement, attic and garage units is moving forward in city council. Bennett Lawson that allows additional dwelling units, known as ADU's "granny flats" in all Chicago neighborhoods.