Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
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Before
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Before
AfterTrusted Home Additions & ADU for Sherman Oaks Homeowners
Home additions and ADU construction in Sherman Oaks typically run $45,000-$130,000 for room additions and $90,000-$220,000 for detached ADUs, with most projects permitted and built within 6-12 months depending on complexity. Rowan Construction Group has delivered 4,000-plus projects since 2007, every one with a written price before work started and a documented photo record when the crew left. We’re the contractor that puts the number in writing first, then builds to it. Call (213) 221-0788 to schedule your free estimate.
Sherman Oaks homeowners bought high between 2015 and 2025, and many now need square footage without the transaction costs of selling in a tight market. A 400-square-foot room addition off a Ventura Boulevard corridor home, a garage conversion ADU behind a house on Valley Vista Boulevard, or a second-story pop-up over a single-story in the hills south of Mulholland - each adds livable space and property value in a zip code where median home prices sit well above the Los Angeles average. We build these projects under The Haven Standard, which means Clause 1 applies: the price is written before anyone picks up a tool.
Grant Rowan founded this discipline in 2007 after watching too many homeowners absorb surprise costs mid-project. Our crews are background-checked and uniformed; a live person answers calls 24/7; and every visit produces a documented photo record included as standard, not an upgrade. If you’re comparing contractors, bring any competitor’s written estimate - we’ll review it line by line at no charge.
What Our Home Additions & ADU Service Includes
ADU Design & Permitting
An accessory dwelling unit, or ADU, is a secondary residential unit on the same lot as a primary home - think a backyard cottage, a converted garage, or a basement apartment with its own kitchen and bath. In Sherman Oaks, ADU design and permitting means navigating the City of Los Angeles Department of Building and Safety, which overlays additional requirements onto the state-mandated ADU laws that apply across California. We prepare architectural plans, structural calculations, and Title 24 energy compliance documentation in-house, then shepherd the package through plan check and correction cycles. Most Sherman Oaks ADU permits clear in 8-14 weeks, though complex hillside lots or properties in the Very High Fire Hazard Severity Zone south of Ventura Boulevard can add time for additional LAFD review.
Garage Conversion ADU
A garage conversion ADU transforms an existing attached or detached garage into a permitted living space with kitchen, bath, sleeping area, and separate entrance. In Sherman Oaks, where many 1950s-1970s homes on streets like Kester Avenue and Longridge Avenue have two-car garages that sit underused, this is often the fastest path to rental income or multigenerational housing. We assess the existing slab for moisture intrusion and structural capacity, upgrade or replace the roof structure to meet current energy code, and run new electrical, plumbing, and HVAC from the main service. A typical garage conversion ADU in Sherman Oaks runs $30,000-$80,000 depending on whether the garage is attached or detached, its condition, and whether the foundation requires reinforcement for the additional load of a kitchen and bath.
New Detached ADU
A new detached ADU is a ground-up structure, separate from the primary residence, built to the same standards as a new home. In Sherman Oaks, these range from compact 400-square-foot studios to 1,200-square-foot two-bedroom units on larger lots in the flatlands near Van Nuys or along the wider lots of Dickens Street. We handle site prep, foundation, framing, roofing, and all MEP (mechanical, electrical, plumbing) systems, plus the separate utility meters or sub-meters required by LADWP and the LA Department of Water and Power’s specific ADU service rules. New detached ADU construction in Sherman Oaks typically costs $90,000-$220,000, with pricing driven by foundation type (slab-on-grade versus raised on piers for hillside lots), roofing material selection, and interior finish level.
Junior ADU & Interior Conversion
A Junior ADU, or JADU, is a smaller unit created within the existing footprint of a single-family home - typically 500 square feet or less, with a kitchenette and separate entrance, sharing bathroom facilities with the main house. In Sherman Oaks and nearby Encino, JADUs work well in the larger ranch-style homes of the Magnolia Woods area or the spacious floor plans along Beverly Glen Boulevard, where a portion of the home can be sectioned off without structural modification. We install fire-rated separation assemblies, sound attenuation between units, and the required independent exterior access. Because JADUs don’t require new foundation or roofing, they typically fall in the lower portion of the addition cost range, though they still require full permitting and HCD (California Department of Housing and Community Development) compliance if any state grant funding is involved.
ADU Site Prep & Utilities
Site preparation for an ADU in Sherman Oaks often uncovers conditions that flatland contractors miss - expansive clay soils that shift with winter rains, mature oak root systems protected by city ordinance, or hillside lots requiring retaining wall engineering. We bring in geotechnical reports when soil conditions warrant, coordinate with SoCalGas for new service lines or meter sets, and work with LADWP on electrical service upgrades that many older Sherman Oaks homes need to support a second dwelling unit. The utility infrastructure is frequently the hidden cost in ADU budgets; we identify these requirements during the free estimate so the written price reflects reality, not optimism.
Room Additions
A room addition expands the existing home’s footprint - a master suite off the rear elevation, a family room extending into the backyard, or a home office carved from a side yard setback. In Sherman Oaks, where R-1 zoning allows floor area ratios that vary by lot size, we verify buildable envelope before design begins, avoiding the costly redesigns that happen when a homeowner falls in love with a plan that doesn’t fit the code. We match existing roof lines, siding materials, and foundation types so the addition reads as original construction, not an afterthought. Room additions in Sherman Oaks typically start around $45,000 for a modest bump-out and climb toward $130,000 for multi-room expansions with high-end finishes.
Second Story Additions
A second-story addition adds a full or partial floor above an existing single-story structure, effectively doubling usable square footage without sacrificing yard space. In Sherman Oaks, where many 1,200-square-foot postwar homes on streets like Noble Avenue and Greenbush Avenue sit on 6,000-plus-square-foot lots, this is often the most efficient path to significant space gain. We assess the existing foundation and wall framing for lateral load capacity, design a stair integration that doesn’t destroy the first-floor flow, and manage the temporary weather protection that keeps the home habitable during construction. Second-story work requires structural engineering and often triggers full seismic retrofit requirements under Los Angeles’s current building code; we bundle these into the project scope and price from day one.
Sunrooms & Enclosed Patios
A sunroom or enclosed patio converts an outdoor living area into a conditioned, habitable space - not a full addition, but a meaningful expansion of usable square footage. In Sherman Oaks, where the climate supports outdoor living eight months a year but January nights drop into the 40s, homeowners often want the glass-wall experience with the option to heat and cool. We install insulated glass units with low-E coatings, integrate the space with the home’s HVAC or specify a dedicated mini-split system, and ensure the slab or foundation meets current code for living space rather than patio-grade construction. These projects typically fall in the $45,000-$85,000 range, depending on whether the existing patio cover can be adapted or must be demolished and rebuilt to structural standards.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Brands We Service for Home Additions & ADU
Our material sourcing runs through fifty-plus vetted brands, which lets us quote honest numbers rather than inflated ones. For roofing on second-story additions and new detached ADUs, we specify IKO architectural shingles on projects where the homeowner wants dimensional appearance at a measured price point - we’ve installed IKO Cambridge and Dynasty lines across hundreds of Los Angeles County roofs and stock their OEM ridge vents and starter strips. On higher-end additions where the roof is a visible design element, we turn to Boral clay and concrete tile, particularly their Saxony and Villa lines that match the Spanish and Mediterranean revival architecture common in the hills above Ventura Boulevard. Boral tile requires specific underlayment and batten specifications that differ from shingle installation; our crews are trained to both standards.
For windows and doors in additions and ADUs, we work with Atlas and Tamko products where the project specification calls for them, and we’re equally comfortable with Andersen, Milgard, or Jeld-Wen when the design or the homeowner’s preference points that direction. Whether you have a specific brand requirement or want us to recommend based on the Sherman Oaks climate - thermal expansion in summer heat, UV exposure, and the occasional Santa Ana wind load - we can help. Every brand we specify is backed by a written warranty, and we document the product labels and installation dates in your project photo record.
Before
AfterSigns You Need Home Additions & ADU Right Now
- Your household has outgrown the existing floor plan. A third child, an aging parent moving in, or a permanent work-from-home arrangement that has colonized the dining room - these aren’t lifestyle preferences, they’re spatial facts. In Sherman Oaks, where many homes were built for 1950s family sizes, the mismatch between programmed space and actual need is the single most common driver of addition projects.
- You’re paying rent for off-site space. A storage unit on Sepulveda Boulevard, a coworking desk in Studio City, or a rental for an adult child - these monthly outflows often exceed the amortized cost of adding square footage. We run this math with homeowners during the free estimate, comparing the 10-year cost of rent against the financed cost of construction.
- The garage has become unusable for vehicles. When a two-car garage holds no cars because it’s packed with belongings, that’s deferred addition square footage. A garage conversion ADU clears the clutter into designed storage and creates income-generating or habitable space in its place.
- You’re considering selling and buying larger. In Sherman Oaks’s current market, the transaction costs of selling - agent commissions, transfer taxes, moving expenses, and the interest rate differential on a new mortgage - often exceed the net cost of adding space to the home you already own. We can show you the comparison.
- Your property has unbuildable yard space. A side yard that collects weeds, a backyard that sees two hours of weekly use, or a driveway that accommodates a third car you don’t own - these are underutilized assets. Los Angeles’s ADU ordinances have made many of these spaces buildable; if your lot qualifies, the question is no longer whether you can build, but whether the numbers work.
Our Home Additions & ADU Process - Step by Step
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Site visit and written estimate. We walk the property, measure the existing structure, photograph conditions, and discuss your program - how many rooms, what functions, what finish level. Within 48 hours, you receive a flat written price with a detailed scope, a timeline, and a list of assumptions. Under Clause 1 of The Haven Standard, this number is fixed unless you request changes; no work proceeds on a change until the change order is signed.
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Design development and permitting. Once you approve the estimate, we produce architectural plans, structural calculations, and energy compliance documentation. In Sherman Oaks, we submit to the Los Angeles Department of Building and Safety Metro office and track plan check status weekly. We handle all correction responses and resubmissions; you don’t interface with the city unless you want to.
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Pre-construction and material procurement. We order long-lead items - windows, roofing, specialty fixtures - immediately upon permit approval to avoid the delays that plague projects where procurement starts after demolition. You receive a documented photo record of material deliveries and a confirmed construction start date.
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Construction with documented progress. Our background-checked, uniformed crews work on a defined schedule with a dedicated project manager. Every visit produces photos of work-in-place, which you access through a shared folder. We hold weekly site meetings to review progress against the written scope and address any field conditions that require discussion.
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Final inspection, closeout, and warranty. We schedule all required city inspections, correct any punch-list items, and deliver your final documentation: as-built plans, permit sign-off, product warranties, and the complete photo record. The 365-Day Done Right Promise begins at substantial completion - if it’s not done right, Rowan makes it right, backed by The Haven Standard, not a handshake.
How Much Does Home Additions & ADU Cost in Sherman Oaks?
Home additions in Sherman Oaks typically range from $45,000 for a modest room addition to $130,000 for extensive multi-room or second-story work. ADU construction runs higher - $90,000-$220,000 for detached units - because of the additional infrastructure: separate utility services, kitchen and bath rough-in, and the standalone structural systems. A garage conversion ADU usually falls in the $30,000-$80,000 range, making it the most cost-effective ADU path for homeowners with underused garage space.
Several factors move the price within these ranges. Foundation work is the largest variable - a slab-on-grade addition on flat land near Ventura Boulevard costs less than a raised foundation on a hillside lot south of Mulholland Drive where grading and retaining walls are required. Finish level matters: builder-grade cabinets and countertops versus KraftMaid or Cambria selections can swing a kitchen-equipped ADU by $15,000-$25,000. Roofing complexity, existing electrical service capacity, and whether the project triggers seismic retrofit requirements all affect the final number.
What affects the price most is what you don’t see during the estimate. We use thermal imaging and moisture meters during our initial site visit to identify conditions that could generate change orders later - roof deck rot, foundation settlement, or outdated electrical panels that won’t support the added load. These findings are documented in your estimate with photos, so you’re choosing whether to address them upfront or not, not discovering them mid-project.
To avoid overpaying, get at least one competing written estimate and bring it to us - we’ll review it line by line at no charge. The free estimate from Rowan Construction Group includes the full scope, the material specifications, the timeline, and the warranty terms. There is no “call for a quote” here; the price is written before any work starts, every time.
Home Additions & ADU Near Sherman Oaks - Our Service Area
We build across the San Fernando Valley and adjacent Westside communities, with typical project sites in Sherman Oaks, Van Nuys, Encino, Studio City, North Hollywood, Beverly Hills, Tarzana, West Hollywood, Brentwood, Northridge, Burbank, and Santa Monica. Drive time from our dispatch to Sherman Oaks is typically under 30 minutes, and project managers make weekly site visits regardless of distance. If you’re unsure whether your property falls within our service area, call (213) 221-0788 - we’ll confirm and schedule your free estimate.
Serving Sherman Oaks, CA - Our Local Coverage Area
We’re based in the Sherman Oaks area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
Frequently Asked Questions - Home Additions & ADU in Sherman Oaks
A home addition expands the existing residence - new rooms, a second story, or an enlarged footprint - while an ADU (accessory dwelling unit) is a separate, self-contained living unit on the same lot, with its own kitchen, bath, and entrance. Additions are typically for the homeowner’s use; ADUs can house family members, generate rental income, or serve as home offices with full residential amenities. In Sherman Oaks, both require city permits, but ADUs benefit from state-mandated streamlining that limits local discretion on approval.
Room additions typically take 3-5 months from permit to completion; ADUs run 6-12 months depending on complexity, with detached units and hillside lots at the longer end. Permitting through the City of Los Angeles adds 8-14 weeks for ADUs, slightly less for straightforward room additions. Call (213) 221-0788 for a timeline specific to your property - we’ll assess the variables during your free estimate.
An ADU in Sherman Oaks runs $90,000-$220,000 for detached construction or $30,000-$80,000 for a garage conversion, while selling and buying larger incurs 5-6% in agent commissions, transfer taxes, moving costs, and likely a higher mortgage rate on the new loan. For many homeowners who bought between 2015 and 2025, the addition or ADU path preserves their interest rate and avoids the transaction costs that would otherwise consume $100,000-plus of equity. Call (213) 221-0788 and we’ll run the comparison with your specific numbers.
Yes - we install IKO and Boral roofing materials regularly on additions and ADUs, and we work with Atlas and Tamko products where the specification calls for them. Our crews are trained to manufacturer installation standards, and we maintain relationships with regional distributors for warranty-registered product sourcing. Whether your project specifies one of these brands or another, we can source and install to code.
We don’t market “emergency” services for planned construction - additions and ADUs are scheduled projects, not dispatch calls. However, if our site work uncovers unexpected structural degradation - termite damage, foundation failure, or compromised framing - we document it immediately, present a signed change order with options, and can often mobilize repair crews within 48 hours to keep the project on schedule. The 24/7 live answering service means you reach a person, not a voicemail, whenever a concern arises.
Every project carries the 365-Day Done Right Promise: if it’s not done right, Rowan makes it right, backed by The Haven Standard with terms documented on every page. Beyond that, manufacturer warranties apply to specific products - IKO shingles carry limited lifetime coverage, Boral tile has its own transferrable warranty - and we register these in your name at project closeout. The workmanship warranty is written in the original estimate, not added later as a sales tool.
Clear personal items from the work area and any access paths, locate your property survey or boundary pins if you have them, and gather any prior permits or plans for the existing structure. We’ll handle utility locates, tree protection planning, and neighbor notifications as required by Los Angeles code. The most important preparation is deciding your budget range and priority list - which features are essential, which are desirable, which can wait - so we can design to a number that works. Call (213) 221-0788 to schedule your free estimate and we’ll walk you through the rest.
Schedule Your Home Additions & ADU Service in Sherman Oaks Today
Call (213) 221-0788 to schedule your free estimate. We’ll visit your Sherman Oaks property, assess the buildable envelope, and deliver a flat written price with a detailed scope before any work starts - that’s Clause 1 of The Haven Standard, and it’s been our practice since 2007. Bring any competitor’s written estimate; we’ll review it line by line at no charge. Your project will be managed by a dedicated project manager, built by background-checked and uniformed crews, and documented with a photo record you’ll have forever. If it’s not done right, we’ll make it right - that’s the 365-Day Done Right Promise, printed on every page, not an asterisk.
Written by Grant Rowan, Owner at Rowan Construction Group, serving Sherman Oaks since 2007.