The ninth annual Alternative Building Materials & Design Expo (AltBuild Expo), featuring over 150 exhibitors in sustainable building and design, will be held from 10 a.m. to 5 p.m. Friday and Saturday, May 11 and 12 at the Santa Monica Civic Auditorium, 1855 Main St.

Presented by the city of Santa Monica and the U.S. Green Building Council-Los Angeles, AltBuild Expo is considered the largest and most-respected green design and building expo in Southern California, expo organizers said. The event serves top industry professionals —architects, builders, contractors, engineers and landscapers — and exhibitors, as well as a large consumer audience.

The expo highlights programming that serves both those already committed to, and those who are poised to enter, sustainable design, organizers note.

Participating in the event are more than 150 exhibitors covering green building and design materials; energy efficiency techniques and technologies; alternative energy; water conservation and management; environmental plumbing; municipal and state agencies; and nonprofit organizations.

This year, the expo also features a curated section of artisan materials and manufacturers.

Although anyone may attend either day, the programming for May 11 is geared to professionals, and on May 12, to the public. More than 40 speakers will address sustainable and alternative building practices.

Admission is free. Parking is $9 for vehicles, and there is free bike valet parking.

Information, (310) 390-2930, or