A CAL FIRE designation for areas at very high risk of wildfire. ADUs in VHFHSZ must meet additional fire-resistance and defensible-space requirements.
Common in hillside neighbourhoods of LA, Berkeley, and other wildland-interface areas. Requirements include Class A roof covering, ignition-resistant siding, ember-resistant vents, and 100 ft of defensible-space brush clearance. Adds $10k-$30k to construction cost vs a non-VHFHSZ project.
Part of the BackyardADU California ADU Glossary — plain-English definitions of the regulatory, construction, and financing terms you'll encounter during a California ADU project.