Home Additions in Los Angeles
Expand your living space with seamless architectural excellence. D&H creates high-end structural expansions that look as if they were always part of the original home.
- Licensed
- Bonded
- Insured
- CA License #B-1084606
Architectural Harmony & Expert Execution
D&H Contractors specializes in structural home expansions that feel as if they were always part of the original design. Our expertise ranges from navigating complex Los Angeles hillside zoning to executing seamless second-story additions in Bel Air and Brentwood.
Every addition is personally led by founder Chris Doria, whose structural engineering
background is exactly what an addition demands. Tying new square footage into an existing foundation, frame, and roofline isn’t decoration — it’s engineering. We manage every phase, from initial architectural drawings and LADBS permit handling to the final master-crafted finish, with one goal: to maximize your property’s value while creating functional, breathtaking living space.
Why Homeowners Choose D&H for Home Additions
Founder-led structural expertise
Additions live or die on the structure beneath them. Chris Doria personally engineers and oversees every tie-in, foundation reinforcement, and load path.
Seamless integration
We match rooflines, proportions, and materials so the addition reads as original — not bolted on.
Zoning & permit mastery
We navigate LA's Baseline Mansionization Ordinance, FAR limits, setbacks, HPOZ review, and hillside rules so your project is feasible before design begins.
Design-build under one roof
Architectural drawings, engineering, permitting, and construction handled by one accountable team.
Westside specialists
Deep experience with the architectural codes and lot conditions of Brentwood, Bel Air, Beverly Hills, and the Palisades.
Types of Home Additions We Build
Second-Story Additions
Double your square footage without sacrificing yard space — ideal for capturing coastal views in Malibu or Santa Monica.
Master-Suite Additions
Create a private sanctuary with walk-in closets, spa-like bathrooms, and integrated outdoor terraces.
Ground-Floor Build-Outs
Seamless single-level extensions that expand kitchens, living areas, or family rooms into the yard.
Standalone guest houses or poolside studios built to Los Angeles County’s latest Accessory Dwelling Unit codes.
Add Up or Add Out?
One of the first questions every addition raises is whether to build up (a second story) or out (a ground-floor extension). The right answer depends on your lot and goals: Building up (second story) preserves your yard and can capture views, but it requires reinforcing the existing foundation and first-floor structure and typically takes. The build-out (ground floor) is often structurally simpler but consumes yard space and can run into setback, easement, and lot-coverage limits.
During our feasibility study, we assess your foundation, structure, lot constraints, and the likely permit path, then recommend the approach that delivers the most value with the fewest surprises.
Structural Precision
Coastal Expertise
Energy Compliant
Fully Insured
Navigating LA Zoning & Permits
Additions are among the most regulated residential projects in Los Angeles — and getting this right early is what separates a smooth build from a stalled one. All structural additions require permits from the Los Angeles Department of Building and Safety (LADBS); there is no size threshold that exempts a structural addition. We handle the entire process, including the pressure points that derail unprepared projects:
- Baseline Mansionization Ordinance (BMO): in R1 zones, residential floor area is generally limited to a set ratio of lot size (FAR), with height typically capped around two stories — the single biggest constraint on LA additions.
- Setbacks, easements, height limits, and the encroachment plane along side yards.
- HPOZ review — Los Angeles has dozens of Historic Preservation Overlay Zones (e.g., Hancock Park, Miracle Mile) where exterior changes require board approval.
- Hillside ordinances and grading review for sloped lots in Bel Air and Palisades.
- Coastal Commission coordination for Santa Monica and Malibu coastal lots.
- Title 24 energy compliance, plus separate building, electrical, plumbing, and mechanical permits.
Plan check almost always returns correction comments before approval — that’s normal. Because we finalize major decisions before plans are approved (late changes can reset the review process) and because an expeditor can compress timelines as needed, we keep your project moving.
Our Seven-Step Process
Consultation & Feasibility
On-site analysis of your lot, foundation, structure, and likely permit path.
Design
Architectural drawings and 3D renderings.
Permitting
LADBS plan check plus HPOZ, hillside, or coastal approvals as required.
Foundation
Structural reinforcement and excavation.
Framing
Shell construction and seamless roof integration.
Finishing
Premium materials and interior detailing.
Handover
Final inspection and project delivery.
A full second-story addition in LA commonly runs several months of construction plus a multi-month design-and-permit phase; ground-floor build-outs are typically faster. We’ll give you a realistic schedule for your specific lot, and we sequence design and permitting in parallel to keep it tight. (Timeline guidance only — no pricing, per your direction.)
Before
After
Featured Additions & Transformations
See how we converted a standard 1950s bungalow into a high-performance modern architectural landmark — and explore more of our seamless Westside expansions.
The Portfolio
The D&H Advantage
Neighborhood expertise
Specialized experience with the architectural codes of Bel Air, Pacific Palisades, and Beverly Hills.
LADBS & zoning masters
We navigate the labyrinth of LA building permits, HPOZ districts, and environmental regulations.
Master craftsmanship
Our crews are artisans, skilled in installing premium materials and handling complex structural engineering.
“D&H transformed our dark, compartmentalized Brentwood home into a luminous masterpiece. Their attention to detail and knowledge of LA building codes was unparalleled.”
Julianne R.
Brentwood Homeowner
“As an architect, I’m picky about execution. D&H is the only contractor I trust for my personal projects. They truly understand high-end luxury materials.”
Marcus T.
Bel Air Estate Owner
Client Perspectives
Neighborhoods We Serve
D&H designs and builds home additions across the LA Westside:
Brentwood
Bel Air
Santa Monica
Pacific Palisades
Beverly Hills
Encino
Frequently Asked Questions
Do I need a permit for a home addition in Los Angeles?
Yes. All structural additions in Los Angeles require LADBS building permits — there is no size threshold that exempts them — plus separate electrical, plumbing, and mechanical permits and Title 24 compliance. D&H handles the entire permit process for you.
How long does a home addition take in Los Angeles?
It depends on the type and the lot. A ground-floor build-out is typically faster, while a full second-story addition takes longer due to structural reinforcement and a longer permit review. We provide a realistic, project-specific schedule after the feasibility study and run design and permitting in parallel to compress it.
How much does a home addition cost in Los Angeles?
Every addition is unique, so the cost depends on the type (build-up vs. out), square footage, structural and foundation work, and your finish selections. Rather than quote a generic number, we provide a detailed, transparent, fixed-price proposal after an on-site feasibility study and design review.
Is it better to build up or build out?
Building up preserves yard space and can capture views, but requires reinforcing the existing structure and faces longer permits; building out is often structurally simpler but uses yard area and can hit setback and lot-coverage limits. We recommend the right approach for your lot during the feasibility study.
What is the Baseline Mansionization Ordinance (BMO), and how does it affect my addition?
The BMO limits how much floor area you can add relative to your lot size (FAR) in many LA residential zones and caps height. It’s the most common constraint on LA additions, which is why we confirm feasibility against it before design begins.
Will my home need to be vacated during the addition?
Sometimes, — especially during the roof-off phase of a second-story addition. We phase the work to minimize disruption and advise you honestly when a temporary move is the safer, faster option.
What areas do you serve?
D&H builds luxury home additions across the LA Westside, including Brentwood, Bel Air, Beverly Hills, Santa Monica, Pacific Palisades, and Malibu.
Start Your Home Addition
Ready to expand your home without compromising its character? Share your vision, and our team will respond within 24 hours to schedule an on-site feasibility consultation.