







A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Room Addition Contractor Across Hollywood
Adding a room to your Hollywood home starts with a clear price and a clear plan. Most room additions in Hollywood run $140,000 to $260,000 for a 400 to 600 square foot space, depending on whether your lot sits on flatland or triggers hillside review. We’ve built across Hollywood from the flats near Melrose Avenue to the winding streets above Beachwood Canyon, so we know what the city’s permitting office will ask for before we even submit your plans. That local knowledge keeps your schedule honest and your price locked. Call (472) 248-8213 to get a written estimate for your addition.
Why Sutton ADU Builders Is Hollywood’s Preferred Room Addition Contractor Company

We’ve handled enough Hollywood additions to know that no two lots here behave the same way. A flat R1 lot off Santa Monica Boulevard permits completely differently than a downslope lot in the Hollywood Hills, and we price accordingly from the first site visit. Homeowners in neighborhoods like Franklin Village and Larchmont have told us the same thing: they wanted a contractor who would tell them the truth about what their specific parcel could handle, not a sales pitch based on a generic template.
Sutton ADU Builders was founded in 2006, and as the ADU-specialist member of the Threshold Group family, we operate under the Threshold Standard on every project. That means a written price before work begins, a 365-Day Done Right Promise covering workmanship for a full calendar year, and a free second visit if any element of the build fails. Every technician who comes to your Hollywood property is background-checked, identity-verified, uniformed, and photo-badged. We send their name and photo to you before they arrive. When you open your door, you know exactly who’s standing there.
Miles Hartwell, our founder, set that standard because he kept hearing from Hollywood homeowners who’d been burned by vague estimates and unfamiliar crews. Our Room Addition Contractor team works the same way whether we’re building a primary-suite addition above Beachwood Canyon or an in-law suite behind a 1920s Spanish-style home near Los Feliz. The 365-Day Done Right Promise is stamped on every project. If the work isn’t right within that year, we make it right.
Home Addition Plans in Hollywood
Home Addition Plans in Hollywood have to account for a lot more than square footage. Before we draft anything, we pull your lot’s zoning record, check its hillside designation, and confirm whether you’re inside the Santa Monica Mountains Conservancy zone or the Baseline Hillside Ordinance boundary. Those two overlays change everything about what your parcel can legally hold: floor-area ratio caps, setback requirements, grading reviews, and sometimes biological sign-offs that flatland additions elsewhere never trigger.
Hillside Lot Review
On a hillside lot above Beachwood Canyon, our crew framed a primary-suite addition with James Hardie siding over a new post-and-beam footprint, then built a board-formed retaining wall for the downslope grade. Because the lot sits in the Baseline Hillside Ordinance area, the plan check included a slope-density and grading review, which added plan-review cycles to the schedule before we could pour footings. That’s the reality of hillside work in Hollywood, and it’s why our written price includes the full scope from day one, not a surprise later.
Flatland Additions
On a flat R1 lot near Hancock Park or the Wilshire corridor, the plans move faster. You still need structural drawings and energy compliance, but the floor-area ratio math is simpler and grading reviews usually drop off. Typical plan sets for a flatland Hollywood room addition run $8,000 to $15,000 including structural engineering, and the city’s plan check typically takes four to eight weeks depending on volume at the Hollywood district office.
In Law Suite Builders in Hollywood

In Law Suite Builders in Hollywood handle a specific kind of room addition: a space with its own entrance, a bathroom, and usually a kitchenette or kitchen. These additions are popular with Hollywood homeowners who want a parent close by or a rental unit that adds monthly income without buying a new property. A 450 square foot in-law suite in Hollywood typically runs $165,000 to $280,000, with the higher end reflecting hillside foundation work, retaining walls, and the cost of running new sewer and electrical lines down a slope.
Detached In-Law Suites
Detached in-law suites in Hollywood often require deeper footings and separate utility trenches. If you’re building behind a hillside home, expect a retaining wall conversation early in the design phase. We’ve built them at the rear of narrow R1 lots where the only access for equipment is a single driveway along the side yard, which adds time but doesn’t have to add surprises if it’s priced into the written estimate.
Attached In-Law Suites
Attached in-law suites convert underused space like a garage or a rear bedroom wing into a self-contained unit. These are usually faster to permit than detached structures, but Hollywood’s hillside overlays can still apply if your lot slopes more than 15 percent. The trade-off is real: attached suites often share a wall with the main house, so sound separation and fire-rated assemblies matter more.
Trusted Brands We Service in Hollywood
We work with several prefab and modular ADU product lines that suit Hollywood’s tight lots and steep grades, including Abodu, Cover, and Dvele. Prefab can shave months off a Hollywood schedule because the modules are built off-site while your site work and foundation go in parallel. We also spec James Hardie exterior systems on many hillside additions because the material handles Hollywood’s hot, dry summers and occasional heavy rain better than wood siding. If you’re weighing a prefab room addition against a conventional build, we’ll walk you through the real cost difference for your specific lot, not a brochure estimate.
Common Room Addition Contractor Problems We See in Hollywood Homes
- Discovering the slope triggers Hillside Construction Regulations mid-plan-check. Homeowners who skip title and lot research sometimes learn after design that their parcel falls inside the Baseline Hillside Ordinance. That forces a redesign, a new floor-area calculation, and months of lost time.
- Quoting off a flat-lot template and missing hillside costs. A soils report reveals deeper foundation depths than expected, or a retaining wall becomes mandatory. That’s a five-figure surprise on a flatland quote, and it happens regularly on Hollywood hillside parcels.
- Assuming an over-the-counter permit. Most single-family room additions in Hollywood R1 zones need a full plan check with structural, grading, and sometimes Coastal or SMMC biological sign-offs. An over-the-counter permit is rare for additions over 200 square feet.
- Older homes with unpermitted prior work. Many Hollywood homes built before 1960 have unpermitted additions or electrical work from decades past. The city may require bringing those to code before signing off on your new addition, which changes the project scope.
Pricing for Room Addition Contractor in Hollywood, CA
A typical room addition in Hollywood runs $140,000 to $260,000. Flatland additions in the 400 square foot range start near $140,000. Hillside additions with retaining walls, deeper footings, and grading reviews typically land between $200,000 and $320,000. Plan sets and structural engineering add $8,000 to $15,000. Permits and impact fees run $6,000 to $18,000 depending on the scope. If your lot sits inside the Santa Monica Mountains Conservancy zone, biological review can add $2,000 to $5,000 in consulting fees. Every Sutton estimate is a written, line-item price before work starts. Call (472) 248-8213 to schedule a free estimate on your Hollywood property.
We Also Serve Cities Near Hollywood
Our crews work throughout the broader Los Angeles basin, including Room Addition Contractor in Hollywood neighborhoods and nearby cities like Los Angeles, Long Beach, Anaheim, and Riverside. If your property sits just outside Hollywood proper, we can still handle the full permit process and build. Call (472) 248-8213 and we’ll tell you straight whether we serve your street.
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 About Room Addition Contractor in Hollywood
Yes, almost always. A room addition in Hollywood over 200 square feet requires a full plan check with structural drawings, energy compliance, and depending on your lot, grading and hillside reviews. Over-the-counter permits are rare for room additions of any real size in Hollywood R1 zones. Call (472) 248-8213 if you want us to check your specific address before you commit to a design.
The Baseline Hillside Ordinance caps your floor-area ratio, which limits how much square footage you can add relative to your lot size. It also triggers grading and retaining-wall reviews that flatland Hollywood lots don’t face. If your parcel sits inside the boundary, your addition may need a slope-density analysis before the city will even accept your plan set. We check this on every hillside lot before drafting plans.
Yes, and many Hollywood homeowners do exactly that. An in-law suite is a room addition with its own entrance, bathroom, and kitchen or kitchenette. The permit classification matters more than the label: a proper accessory dwelling unit gets its own address and utility connections, while a junior ADU stays attached to the main house. Call (472) 248-8213 for a free estimate and we’ll explain which classification fits your lot.
Plan for eight to fourteen months from contract signing to final inspection. Hillside lots inside the Baseline Hillside Ordinance area run longer because grading reviews and structural plan checks add four to eight weeks to the permitting phase alone. Flatland additions in Hollywood typically finish in eight to ten months. The schedule is part of your written estimate, so you’ll see it in writing before work starts.
Only two things: you change the scope, or the city requires something extra after plan check. A soils report may reveal deeper foundation needs than the original plan assumed. The city may flag unpermitted prior work that must be brought to code. Those are the honest variables. Our written price stays fixed unless you ask for a change order, and we never pass silent scope creep to your bill. Call (472) 248-8213 to get a written estimate for your Hollywood addition.
Written by Miles Hartwell, Owner at Sutton ADU Builders, serving Hollywood and the broader Los Angeles basin since 2006.


