Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
After
Before
After
Before
AfterFast, Reliable Home Additions & ADU Across Hollywood
A home addition or ADU in Hollywood typically costs between $45,000 and $130,000 for a room addition, and $90,000 to $220,000 for a new detached ADU, depending on whether your property falls inside an HPOZ historic district or triggers the city’s soft-story seismic retrofit ordinance. We’re Barrett & Sons Construction, and we have been working in Hollywood’s older housing stock long enough to know that the price on paper changes the moment a permit review finds something the last contractor ignored. Call (877) 610-1318 for a free estimate, and we’ll walk the property with you before anyone quotes a number.
Why Barrett & Sons Construction Is Hollywood’s Preferred Home Additions & ADU Company
Tom Barrett started this company in 1998, and he still answers his own phone. That matters in a neighborhood like Hollywood, where homeowners get flyers from national outfits every week and calls from out-of-area contractors who do not know what the LA Office of Historic Resources is. Our crew members carry the Barrett & Sons name on their trucks and their uniforms. Tom’s sons run the crews, and Tom is on-site most days. When you call about a garage conversion off Santa Monica Blvd or a second-story addition up in the Hollywood Hills, you talk to someone who has actually worked those streets.
Hollywood homeowners tell us the same story again and again: a contractor quoted one price on the phone, showed up with another number, and disappeared when the permit office asked questions. Our answer to that is simple. Every scope, every allowance, every price change arrives as a written change order before work happens. Permits get pulled on every eligible job. Inspections get signed. And every project is backed by the written 90-Day Done Right Promise. If it is not done right, Tom comes back and makes it right, one call. That promise is written on the contract, not buried in fine print.
We serve all of Hollywood’s 90028 zip code, from the flatland apartment corridors to the hillside lots that need slope work most contractors will not touch. Ask anyone on your street, or look up the license number yourself. Tom Barrett publishes his name, his address, and his license number. We want you to check before you sign anything.
Our Home Additions & ADU Services in Hollywood
ADU Design & Permitting
The permit path for an ADU in Hollywood is not the same as it is in North Hollywood or Van Nuys. If your property sits inside a Historic Preservation Overlay Zone, your design goes through the LA Office of Historic Resources before you get a permit. That review step can add two to four weeks to a schedule that a flatland LA contractor would never budget for. We handle the drawings, the submittals, and the corrections. Our Home Additions & ADU team has been through this process enough times to know which window details and door styles will pass HPOZ review without a back-and-forth.
Garage Conversion ADU
Garage conversions in Hollywood run $30,000 to $80,000, and the price depends heavily on what the existing structure was built for. Many Hollywood garages date to the 1920s and 1940s, with wood-lath plaster, old slab foundations, and electrical panels that were never meant to feed a dwelling unit. Some sit in courtyard bungalow complexes where exterior changes trigger HPOZ design review. We handle the structural checks, the utility upgrades, and the design review paperwork in one pass. No surprise stop-work orders weeks into the job.
New Detached ADU
A new detached ADU in Hollywood runs $90,000 to $220,000. On a flatland lot west of the 101, that buys you a full one-bedroom unit with its own address, its own panel, and its own meter. On a hillside lot in the Hollywood Hills portion, the same project may need a soils report, a slope analysis, and a deeper foundation than the flatland price assumes. We write those conditions into the contract before we start, not after.
Junior ADU & Interior Conversion
A Junior ADU is the fastest route to a legal rental unit inside an existing Hollywood home, often using a spare bedroom, a converted den, or a finished basement. These projects typically stay under the full ADU price range but still trigger electrical, egress, and fire-safety upgrades once walls come open. On a 1920s Spanish Colonial Revival courtyard apartment in the Hollywood Grove HPOZ, our crew opened a load-bearing wall for a Junior ADU and found knob-and-tube wiring and wood-lath plaster with failed waterproofing behind the original clay tile. We pulled a permit amendment, wrote the rewire and shear-wall upgrade into a change order, and got inspection sign-off from both the city and the Office of Historic Resources before closing the wall. That is how we work in Hollywood. Open it once, see what is actually there, price it in writing, then build it right.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Hollywood
We install brands you can look up, not mystery products off a van. On ADU window packages and second-story addition glazing, we regularly install Simonton and Ply Gem windows because they hold up to Hollywood’s sun exposure and meet California Title 24 energy requirements without a fight. For exterior door packages on hillside additions that handle driving rain and Santa Ana wind, we use PGT impact-rated products where the design calls for it. If you already have windows or doors from one of these brands on your Hollywood home, we can match them on the addition so the new work does not look pasted on.
Common Home Additions & ADU Problems We See in Hollywood Homes
Hollywood’s building stock layers early-20th-century Craftsman bungalows and 1920s-to-1940s Spanish Colonial Revival courtyard apartments over a dense stratum of 1950s-to-1970s soft-story wood-frame apartment buildings with tuck-under parking. That mix means a single block can require both historic-sensitive restoration work and structural steel moment-frame installation. Here is what we run into most often.
- Soft-story retrofit stop-work orders. If your 1960s apartment building has tuck-under parking and you start an ADU conversion without checking the city’s mandatory seismic retrofit deadline, the permit can trigger the full retrofit scope. Suddenly your garage conversion includes steel moment frames at the parking level. We check that deadline before we quote.
- HPOZ design review rejections. A garage conversion in a courtyard bungalow complex is not the same permit path as a flatland LA job. The LA Office of Historic Resources reviews exterior door and window changes, and a rejection weeks into the project costs you time and money. We submit window details and door styles that pass the first time.
- Knob-and-tube and failed waterproofing behind original walls. When you open a load-bearing wall in a 1920s Hollywood bungalow, expect old wiring and plaster that has been holding water for decades. The permit inspector will flag it. We write those discoveries into the contract as allowances, so the price change arrives on paper before we touch it, not as a surprise invoice at the end.
- Hillside soils and steep-slope grading. Hollywood sits at the base of the Santa Monica Mountains. A room addition or second-story project in the hills needs a soils report and possibly a grading permit. Expansive hillside soils can require a deeper foundation than the original quote assumed. We write the soils report into the scope from day one, because the allowance that is not on paper is a surprise waiting for a date.
Pricing for Home Additions & ADU in Hollywood, CA
Home addition and ADU pricing in Hollywood reflects what is under the surface, not just what is on the plans. A standard room addition runs $45,000 to $130,000. A new detached ADU runs $90,000 to $220,000. A garage conversion runs $30,000 to $80,000. Where your project lands inside those ranges depends on HPOZ design review, soft-story retrofit triggers, hillside soils, and what we find when we open the walls. Here are the line-item ranges we quote in Hollywood.
| Project Type | Hollywood Price Range |
|---|---|
| Home Addition | $45,000 - $130,000 |
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion | $30,000 - $80,000 |
Every quote from Barrett & Sons Construction includes a line item for allowances, because we know from experience that a 1920s Hollywood wall hides things. When a surprise shows up, you get a written change order with a price before any work proceeds. No change orders, no work. That is the rule. Call (877) 610-1318 to schedule your free estimate, and we will give you numbers you can actually plan around.
We Also Serve Cities Near Hollywood
While this page is about Home Additions & ADU in Hollywood, we also work regularly in Universal City, West Hollywood, Koreatown, and Echo Park. The permit offices and design review boards differ across those jurisdictions, but the way we write contracts does not. If you are just outside the 90028 boundary, call us and we will tell you straight what applies to your property.
Serving Hollywood, CA - Our Local Coverage Area
We’re based in the Hollywood area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - Home Additions & ADU in Hollywood
Yes. If your Hollywood property sits inside a Historic Preservation Overlay Zone, any exterior alteration that touches your ADU or home addition, including window changes, door changes, stucco repair, or re-roofing, requires sign-off from the LA Office of Historic Resources before a permit is issued. That review can add weeks to a schedule. We submit window details and door styles that are designed to pass the first time, so the review does not turn into a months-long negotiation. Call (877) 610-1318 and we will check your property’s HPOZ status before you spend a dollar on drawings.
It very likely does. Hollywood’s flatland residential corridors are dense with 1960s and 1970s wood-frame apartment buildings that fall under the City of Los Angeles mandatory soft-story seismic retrofit ordinance. If your building has tuck-under parking and has not completed its retrofit, pulling a permit for an ADU can trigger the full retrofit scope, including steel moment frames at the parking level. We check the retrofit deadline and status before we quote, so you know the real project scope on day one. Call (877) 610-1318 for an exact read on your building.
We stop work on that wall, document what we found, and write the rewire into a change order before we touch another stud. In a 1920s Hollywood bungalow or Spanish Colonial Revival courtyard apartment, knob-and-tube wiring and wood-lath plaster are common. The permit inspector will require the upgrade once the wall is open. Because we write allowances into every Hollywood contract, the price change arrives on paper and you approve it before we proceed. That is why our contracts include an allowances line item. Call (877) 610-1318 and we will explain exactly how allowances work on your project.
Yes. Hollywood sits at the base of the Santa Monica Mountains, and the Hollywood Hills portion brings steep-slope grading permits, expansive hillside soils, and post-wildfire erosion and drainage requirements that flatland contractors do not handle. A second-story addition on a hillside lot typically needs a soils report first, and the report may require a deeper foundation than the original quote assumed. We write the soils report into the scope from the start, so the price you approve is the price that reflects the actual hillside conditions. Call (877) 610-1318 for a free estimate that includes the slope work.
Because a Hollywood remodeling quote that does not include allowances is a surprise waiting for a date. When we open a wall in an older home and find knob-and-tube wiring, failed waterproofing, or undersized framing, the fix has a price. An allowance line item means that price is written into the contract before we start, and any change comes to you as a written change order before work proceeds. You approve the number, then the work happens. No surprise invoices at the end. Call (877) 610-1318 and we will walk you through a sample contract so you see exactly how allowances work.
Ready to Plan Your Hollywood Home Addition or ADU?
Start with a free estimate and a straight conversation about what your property actually needs. Hollywood’s HPOZ design review and soft-story retrofit deadlines are not optional, and the wrong permit path can cost you months. We know the 90028 streets, the hillside lots, and the courtyard bungalow complexes. Tom Barrett and his sons will walk your property, explain what applies, and put every scope and every allowance in writing before a single nail moves. Call (877) 610-1318 today. A live person answers, 24/7.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Hollywood and the surrounding neighborhoods.