Home Additions & New Construction
Room additions, second stories, garage conversions, and ground-up custom homes across Los Angeles.
Home Additions & New Construction in Los Angeles
Adding square footage is the most structurally complex residential project you can take on — new foundations, structural connections to existing framing, roof tie-ins, and full MEP (mechanical, electrical, plumbing) extensions. Alto Builders has the engineering relationships and field experience to get it done right.
We build from architectural plans or lead design-build with our in-house team. Lana handles 3D modeling in Chief Architect, and we coordinate with structural engineers, soils engineers, and surveyors as needed. Every project gets a Buildertrend portal with daily photo logs, a shared schedule, and real-time budget tracking. CSLB #1118841.
What We Build
- Room Additions — Single-room additions for bedrooms, offices, or in-law suites. We match the existing roofline, siding, and foundation type so it looks original, not tacked on.
- Second Story Additions — Full second-floor additions with new staircase, structural reinforcement of the existing first floor, seismic upgrades, and complete MEP to the new level. These typically require a structural engineer and soils report.
- Garage Conversions — Convert an attached or detached garage into a bedroom, office, or ADU. We handle the change-of-use permit, insulation, drywall, flooring, HVAC, and a new compliant entry.
- Ground-Up New Construction — Custom homes from cleared lot to certificate of occupancy. We work from architect plans or design-build. Foundation, framing, roofing, MEP, insulation, drywall, finishes, landscaping.
- Outdoor Living Structures — Covered patios, outdoor kitchens with gas and plumbing, pool houses, and detached guest houses. We pull separate permits for structures with electrical or plumbing.
Our Process
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Design & Feasibility We visit your property, review your goals, and assess what's structurally and code-feasible. You'll get a rough scope, ballpark budget, and timeline estimate.
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Plans, Engineering & Permits Architectural drawings, structural engineering, soils reports if needed, Title 24 energy calcs, and permit applications. Permit timelines in LA range from 6 weeks to 6 months depending on scope and jurisdiction.
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Construction Site prep, foundation, framing, roofing, rough MEP, insulation, drywall, finishes, fixtures, and final grading. Daily Buildertrend updates. We coordinate all subcontractors and inspections.
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Final Walkthrough & CO Final inspection with the city, certificate of occupancy, punch list review, and warranty documentation.
Recent Projects
Projects we've built or are currently building. Click through for photos and details.
- Encino Custom Home — In progress, ground-up custom home in Encino.
- Venice Canal Residence — Full custom home on the Venice canals.
- Malibu Midcentury Modern — Midcentury modern renovation and addition in Malibu.
- Valley View Eclectic Refresh — Full home refresh in Woodland Hills.
Areas We Serve
Alto Builders provides home addition and new construction services across Los Angeles and the surrounding area, including Encino, Sherman Oaks, Studio City, Woodland Hills, Calabasas, Westlake Village, Thousand Oaks, Agoura Hills, Santa Monica, Pasadena, Tarzana, Brentwood, Pacific Palisades, Malibu, Topanga, Hidden Hills, Oak Park, Moorpark, Simi Valley, Burbank, Glendale, and North Hollywood.
Frequently Asked Questions
Room additions typically run $250–$450 per square foot in LA, so a 400 sq ft addition is $100,000–$180,000. Second stories cost more due to structural reinforcement — $300–$500/sf is typical. Ground-up new construction runs $350–$600/sf depending on finishes and complexity. We provide a fixed-price contract after the design and engineering phase.
A room addition takes 4–6 months from permit to completion. A second story addition runs 6–10 months. Ground-up new construction is typically 10–18 months. Add 2–6 months for design, engineering, and permits before construction starts.
Always. Any structural work, foundation work, or new square footage requires permits, structural engineering, and typically a soils report. We handle all of it — plans, applications, plan check corrections, and inspections.
Room additions (bedrooms, offices, in-law suites), second story additions, garage conversions, ground-up custom homes, ADUs, pool houses, and detached guest houses. We also do major renovations that combine an addition with a full interior remodel.
Ready to Expand Your Home?
Whether you need an extra room, a second story, or a custom home from the ground up — it starts with a conversation. We are here to help you understand your options and build something that fits your life.