Home Additions & ADU in Los Angeles - One Fixed Price, Permits Handled

Fast, Reliable Home Additions & ADU Across Los Angeles

Home additions and ADU construction in Los Angeles typically run $53,100 to $153,400 for room additions and $106,200 to $259,600 for detached ADUs, with permits adding 3 to 6 months to most schedules. Rowan Construction Group serves Los Angeles from our local metro office, with crews experienced in the specific conditions that define construction here: pre-1978 wood-frame housing stock, mandatory seismic retrofit ordinances, and LADBS plan-check backlogs that shape every timeline. Call (213) 221-0788 to schedule your free estimate.

Call (213) 221-0788

Why Rowan Construction Group Sherman Oaks Is Los Angeles’s Preferred Home Additions & ADU Company

We’ve delivered more than 4,000 projects since 2007, every one with a written price before work started and a documented photo record when the crew left. In Los Angeles specifically, our reputation rests on how we handle what opens up behind old walls - the knob-and-tube wiring, the undersized framing, the failed waterproofing - without surprising the homeowner with an open-ended invoice.

Our Los Angeles customers mention the same things in reviews: the quote was flat, the change order was signed before any extra work happened, and the final number stayed within a few percent of the original. That’s Clause 1 of The Haven Standard, and it’s how we’ve operated since Grant Rowan founded the company.

Dispatch and scheduling run from our Los Angeles office, so crews respond to Highland Park, Koreatown, the Valley, and the hillside neighborhoods without the delays of routing from outside the metro. Calls are answered by a live person 24/7, and every technician is background-checked and uniformed.

We know the local building stock because we’ve opened it: 1920s Craftsman bungalows with original mudsills, post-WWII tract homes in the San Fernando Valley with shallow foundations, soft-story apartment buildings in Hollywood and West LA that trigger mandatory retrofit work before any addition can proceed. This isn’t generic experience. It’s Los Angeles-specific.

Our Home Additions & ADU Services in Los Angeles

ADU Design & Permitting

Los Angeles ADU permits move through LADBS on a timeline that experienced contractors plan for, not hope around. We build 3-to-6-month permit lead times into every schedule, and we file complete plan sets that include structural calculations, Title 24 energy compliance, and - for pre-1978 structures - seismic retrofit documentation that satisfies the Soft-Story or Non-Ductile Concrete ordinances if triggered. Our design team produces construction-ready drawings, not concept sketches, so the plan checker has fewer reasons to kick the set back.

Garage Conversion ADU

Garage conversions in Los Angeles run $35,400 to $94,400 and represent one of the faster paths to rental income, but they carry specific local complications. Many Los Angeles garages sit on slabs without footings adequate for habitable space, or they share a foundation with the main house in ways that complicate seismic separation. We inspect the slab, the framing, and the utility path before quoting, then write any needed foundation or seismic upgrade into the flat price - not as a surprise later.

New Detached ADU

Detached ADUs are where Los Angeles’s zoning and geography get interesting. On flat Valley lots, a 750-square-foot unit is relatively straightforward. On hillside properties in Laurel Canyon, Beachwood Canyon, or Mount Washington, fire-hardened construction requirements kick in: ember-resistant vents, Class A roofing, tempered glazing, and often engineered caisson or grade-beam foundations that wouldn’t be necessary on level ground. Those hillside conditions add cost and complexity, and we price them explicitly in the written quote.

Junior ADU & Interior Conversion

Junior ADUs - converted from existing interior space within the main house - avoid some permit delays but expose more of the original structure to inspection. In Los Angeles’s older housing stock, that often means opening walls to find conditions that haven’t been visible in decades. We handle JADU conversions in neighborhoods from Highland Park to West Adams, and we build inspection-first allowances into every contract for the wiring, plumbing, and structural conditions we’re likely to find.

Room Additions

Room additions in Los Angeles attach to existing structures that may not have been built to carry the new load. We see this constantly in 1920s and 1930s bungalows where the original 2×4 ceiling joists can’t span the new opening, or in post-WWII Valley tract homes where the foundation was never designed for a second story. Our process starts with a structural assessment, not a sales pitch, and the written quote includes engineered solutions where needed.

Second Story Additions

Second story additions trigger the most intensive inspection of any project type. In Los Angeles, they almost always require seismic evaluation: shear walls, anchor bolts, hold-downs, and often a full Soft-Story Retrofit if the existing structure falls under the city ordinance. We price the structural and seismic work as line items in the original quote, not as a post-demolition surprise. The alternative is an open-ended project that bleeds into the LADBS backlog for months.

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Trusted Brands We Service in Los Angeles

Rowan Construction Group sources across fifty-plus vetted brands, and for ADU and addition projects in Los Angeles we regularly specify Dvele and Plant Prefab for panelized and modular components that reduce on-site construction time - a significant advantage on hillside lots with narrow access or in neighborhoods where street parking for construction vehicles is restricted. We also evaluate Mighty Buildings and Boxabl where their systems match the project scale and zoning. Every brand is priced into the written quote at wholesale rates, not inflated retail, and we stock or locally source so material lead times don’t extend the already-lengthy permit schedule.

Common Home Additions & ADU Problems We See in Los Angeles Homes

• Knob-and-tube or aluminum wiring behind opened walls. We find this regularly in pre-1950s Los Angeles homes, especially in Highland Park and Echo Park. Once exposed, it must be replaced to pass electrical inspection, and we build a wiring allowance into every contract for homes of this vintage.
• Undersized or damaged framing that can’t carry new loads. Original 2×4 ceiling joists in 1920s Craftsman bungalows and shallow-pitch roofs in post-WWII Valley tract homes often need engineered upgrades for second stories or large room additions. We assess this before demolition and price the structural work upfront.
• Failed waterproofing at old stucco-to-foundation transitions. Common in hillside homes from Beachwood Canyon to Mount Washington, this turns a simple addition into a caisson or grade-beam foundation job with new engineering and extended LADBS review.
• Soft-story conditions triggering mandatory retrofit. In Koreatown, Hollywood, and West LA, two-story apartment buildings with tuck-under parking fall under the city’s Soft-Story Retrofit Ordinance. Any addition or ADU work on these structures requires retrofit compliance integrated into the permit set.

Pricing for Home Additions & ADU in Los Angeles, CA

We Also Serve Cities Near Los Angeles

Our Home Additions & ADU in Los Angeles crews work throughout the metro, including Culver City, West Hollywood, Beverly Hills, and Glendale. Each city carries its own permit authority and zoning specifics, and we file and track permits locally rather than applying a one-size template.

FAQs - Home Additions & ADU in Los Angeles

Contact Rowan Construction Group for Your Los Angeles Home Addition or ADU

We’re the construction contractor that puts the number in writing before anyone picks up a tool. For home additions and ADU projects in Los Angeles, that means a flat written price, a written scope, and a documented record of every visit - including the conditions we find behind your walls and how we handled them. The 365-Day Done Right Promise backs every project, and our Free Second Opinion offer stands for any written estimate you want reviewed.

Call (213) 221-0788 to schedule your free estimate. A live person answers 24/7.

Written by Grant Rowan, Owner at Rowan Construction Group, operating under The Haven Standard since 2007.