Honolulu Mayor Kirk Caldwell today allowed to become law a comprehensive bill aimed at stemming the number of monster houses and other large-scale residential structures that have been sprouting in Oahu’s older neighborhoods in recent years.

Caldwell said that while he supports regulation of out-sized houses being used for unscrupulous reasons, he is not signing the measure as approved by the City Council because he believes it will lead to unintended consequences on legitimate builders.

The Council voted on April 17 to pass Bill 79 (2018) by a 9-0 vote so an override vote likely would have nullified a veto anyway.

The mayor said the bill has provision that will force unnecessary mandates on those who may wish to renovate existing older homes.

Under Bill 79 (2018), the maximum density of a detached dwelling would not be allowed to have a floor area greater than 70% of a lot’s size, or what’s known as a floor area ratio (FAR) of 0.7.

Any house with an FAR greater than 0.6, however, would need to be owner- occupied and be subject to additional rules. Specifically, they would have to have 8-foot side and rear yards and be able to obtain a temporary certificate of occupancy for only up to a year, during which time the Department of Planning and Permitting (DPP) could inspect the house.

The Council has been wrestling for several years with how to curb the proliferation of monster houses that go up quickly, often defy city building rules and dwarf other homes in older residential neighborhoods. Critics say the structures overburden street parking and infrastructure and are often used as illegal rentals, vacation homes or other nonconforming businesses.

The uproar over monster houses also has triggered a backlash from legitimate homebuilders and the Building Industry Association of Hawaii, who worry that new regulations might go too far and create delays in obtaining building permits from DPP — a process they say already takes too long at a time when there’s a huge demand for housing on the island.

Other provisions of the new law:

>> A minimum of two on-site parking stalls are required, plus one stall for each additional 750 square feet over 2,500 square feet (excluding carports and garages).

>> The definition of bathrooms require either a sink, a toilet or both. Additionally, houses up to 5,999 square feet would be allowed up to 4-1/2 bathrooms under a sliding scale, although Pine said she wants to work further on lowering the number allowed for larger homes.

>> Converting or altering a wet bar, laundry room or bathroom are prohibited unless specifically allowed under a valid building permit.

>> A limit of 75% of a property can be covered with an impervious surface, such as concrete or asphalt.