The Van Nuys HPOZ Actually Reviews Roofs
Unlike most of the Valley, part of Van Nuys carries a genuine, regulatory Historic Preservation Overlay Zone, adopted by city ordinance on November 16, 2005 and effective January 8, 2006. The boundary runs roughly along Kittridge, Vanowen, Haynes, Hamlin, Lemay, Archwood, Cedros, Vesper, Van Nuys, Sylmar, Tyrone, Lennox, Hazeltine and Katherine, per the city's own survey documentation.
Inside that line, changing a contributing house's roof material or visible profile isn't just a building-permit question, it goes through HPOZ Board or staff review first, which looks at whether the work keeps the house's original character. Outside the boundary, a standard LADBS permit applies as it would anywhere else in the Valley.