ADUs & Additions in La Crescenta-Montrose

Los Angeles County Department of Public Works, Building and Safety Division. La Crescenta-Montrose is unincorporated, so building permits come from Los Angeles County Public Works Building and Safety, with applications filed through the EPIC-LA portal. The community's zoning also carries the La Crescenta-Montrose Community Standards District, which the Board of Supervisors folded into the West San Gabriel Valley Planning Area Standards District in March 2025 as County Code Section 22.320.120. On R-1 lots of 7,500 square feet or more it caps Gross Structural Area at a quarter of net lot area plus 1,000 square feet, counting the floor area of all enclosed buildings and structures except cellars and the first 400 square feet of garage, and on R-1 lots it requires fully shielded fixtures for permanent exterior lighting. Addresses reading La Crescenta or Montrose can also fall inside the City of Glendale, which handles its own permits, so jurisdiction is confirmed parcel by parcel. We prepare the drawings, make the submittal and handle plan-check corrections ourselves, so you are not the one chasing plan check.

Predominantly single-family streets, with commercial uses concentrated along Foothill Boulevard. The homes run mostly to Spanish Colonial Revival, Craftsman, Minimal Traditional, Tudor, Ranch and Colonial Revival styles, and in County Assessor parcel data about half of the single-family lots are 7,500 square feet or larger, the size at which the Gross Structural Area cap applies on R-1 lots. One local condition that shapes the work: Large parts of the community, from the Angeles National Forest edge down across much of the valley floor, are mapped Very High Fire Hazard Severity Zone. The County's 2026 fire-zone construction notes require any attached or detached patio cover, trellis, arbor or gazebo within 50 feet of the house to be noncombustible, ignition-resistant or heavy timber, and the property must meet vegetation management requirements before permit final.

All of it, including La Crescenta, Montrose and Foothill Boulevard corridor. Our crews run every job out of our Cahuenga Pass base in Los Angeles, with our own people on site.

Detached ADU: generally $150,000 to $400,000+ across Southern California. What moves it is square footage, finish level, utility runs, and site access; garage conversions typically run well below a ground-up detached build. We give line-item pricing after seeing the site rather than quoting a number over the phone.

Plan a realistic year. Design and engineering typically take one to three months, city plan check and corrections add several more, and construction usually runs four to eight months depending on size and site access.

Usually yes, and often substantially, because the foundation, walls and roof already exist. The trade-offs are that you lose the garage, and older slabs and framing sometimes need upgrading to meet current code.

California ADU law is designed to allow long-term rental, and an ADU is one of the few ways to add rentable square footage to a single-family lot. Short-term rental rules vary by city, so confirm your local ordinance before counting on that income.

Yes. Plans, engineering, Title 24 and the city submittal are all handled in-house, including responding to plan-check corrections. That is a service we sell on its own, so it is not something we hand off.