A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateTrusted ADU Builders for San Diego Homeowners
An ADU, or accessory dwelling unit, is a second, fully independent home built on the same lot as your main house. In San Diego, that usually means a backyard cottage, a garage conversion, or an attached suite with its own kitchen, bath, and entrance. We’re Lodgewick ADU San Diego, ADU Builders - San Diego and the ADU company of the Kingswell family. Since 2010, we’ve specialized in accessory dwelling units, garage conversions, and home additions across San Diego County. Every project runs under The Kingswell Guarantee: a written price before work begins, a real arrival window, a clean job site, and a written guarantee on every build. Russ Delmar leads our team, and he’s held the same standard for over a decade. Call (619) 376-2760 for a free estimate.
Key Takeaways
- A detached ADU in San Diego typically runs $180,000 to $450,000 depending on size, site conditions, and finish level.
- Garage conversions and JADUs generally cost less, often landing between $90,000 and $180,000.
- Lodgewick provides a written price before any work starts, with no price changes at the door.
- The 365-Day Done Right Promise covers every project in writing, with a free return visit if the work fails within the warranty period.
- We work with leading prefab brands including Boxabl, Plant Prefab, and James Hardie products.
ADU Construction
ADU Construction is the full process of planning, permitting, building, and finishing an accessory dwelling unit on your existing property. In San Diego, most homeowners come to us when they need more space for aging parents, adult children, or rental income, and they want the entire job handled by one team instead of juggling architects, engineers, and separate contractors. A typical ADU construction project in San Diego runs $180,000 to $450,000 depending on square footage, site access, and whether you choose site-built or prefab. We handle everything from the first site walk to final inspection, with a written price before any work starts and the 365-Day Done Right Promise included on every project.
Site-Built vs. Prefab Construction
Site-built ADUs are framed on your lot, which gives you full control over layout and finishes. Prefab options from brands like Boxabl and Plant Prefab arrive as factory-built modules that get craned into place, which can cut weeks off the schedule. We walk you through both approaches and price each one in writing so you can compare without pressure.
Permitting and Inspections
Every ADU in San Diego requires city permits, and the process has gotten faster under recent state and local ADU laws. We pull permits, schedule inspections, and handle rejections when they come up. Our clients never have to chase the city themselves.
Detached ADU
A Detached ADU is a standalone structure built in your backyard, fully separated from your main home, with its own foundation, utilities, kitchen, bathroom, and addressable entrance. This is the most common ADU type in San Diego because it gives homeowners true rental privacy and the most flexibility in design and placement. A detached ADU in San Diego typically costs $200,000 to $450,000 to build, depending on soil conditions, distance from utility connections, and the finish package you choose. At Lodgewick ADU San Diego, we’ve built detached units on sloped lots in Normal Heights, flat lots in Poway, and tight rear yards in La Mesa, so we know what the ground and the city will throw at a project.
Lot and Utility Considerations
San Diego has thousands of lots with canyon views and tricky slopes. That’s a feature for your home, but it affects trenching, foundation work, and crane access for prefab. We price for the actual conditions on your lot, not a generic square-foot formula.
Placement and Setbacks
City setback rules determine how close your detached ADU can sit to property lines and existing structures. We measure, verify, and design around those constraints before you spend a dollar on construction. A written plan that respects setbacks saves you from costly redesigns later.
JADU
A JADU, or junior accessory dwelling unit, is a smaller unit created within the existing walls of your single-family home, usually by converting a bedroom, attached garage, or underused space into a compact living area with its own efficiency kitchen and entrance. It’s capped at 500 square feet under California law, which makes it the most affordable way to add rentable space in San Diego. A JADU in San Diego typically costs $90,000 to $170,000 depending on whether you’re converting finished interior space or taking over an attached garage. The Kingswell Guarantee applies exactly the same way: written price first, written guarantee included.
JADU vs. ADU: What Changes
A JADU overlaps with your main house, so utility connections are simpler and the permit path is different from a detached unit. The trade-off is size and sometimes parking requirements. We explain the differences in plain English, then give you a written quote for whichever route fits your budget.
Ideal JADU Conversions
Attached garages and large first-floor bedrooms are the most common JADU conversions in San Diego. Because these spaces already have structure and roof, the job moves faster than a ground-up build. We’ve converted attached garages with ADU Builders in Chula Vista and La Mesa where the homeowner kept the exterior look nearly unchanged.
ADU Plans
ADU Plans are the architectural drawings, engineering calculations, site plans, and permit documents required to get your accessory dwelling unit approved by the City of San Diego before construction starts. You need ADU plans whenever you’re building any new structure, converting a garage, or adding an attached unit, and getting this stage wrong is what delays most San Diego ADU projects. We produce or coordinate complete ADU plan sets for every project, and the plan phase typically costs $8,000 to $25,000 depending on site complexity, soil reports, and whether structural engineering is required. Lodgewick ADU San Diego includes plan costs in your written total, so there’s no surprise line item after you’ve signed.
What a Complete Plan Set Includes
Our plan sets cover floor plans, elevations, electrical and plumbing layouts, and Title 24 energy compliance. We also coordinate with San Diego’s permitting office for plan checks and resubmittals. When you work with us, you won’t be handed a stack of drawings and left to figure out the building department on your own.
Plan Accuracy Saves Construction Money
The most expensive change orders come from plans that don’t match the actual site. We measure your lot ourselves, verify utility locations, and make sure the drawings reflect reality. Accurate ADU plans mean fewer surprises when the concrete truck shows up.
ADU Contractor
An ADU Contractor is the licensed general contractor responsible for turning your approved plans into a finished, habitable accessory dwelling unit. You need a dedicated ADU contractor rather than a general remodeler because ADUs have specific code requirements, a distinct permit path, and utilities work that a kitchen remodel outfit rarely handles well. Lodgewick ADU San Diego is that contractor: we manage scheduling, subcontractors, inspections, materials, and the job-site cleanup every day until the final walkthrough. Our San Diego ADU projects typically run $180,000 to $450,000 all-in, with the price written and fixed before we start.
What We Manage On Your Behalf
We handle framing, roofing, electrical, plumbing, HVAC, drywall, paint, flooring, and all the inspections in between. Background-checked, uniformed technicians show up in the window we give you, every time. You get a single point of contact at our office, reached through a live person, not a voicemail tree.
Why a Dedicated ADU Team Matters
ADUs involve site work, foundation, utility runs, and sometimes prefab module coordination all at once. A general remodeler may not have relationships with prefab manufacturers or experience pulling ADU-specific permits. Russ Delmar and our team have done this work in San Diego since 2010, and it shows in the schedule and the final quality.
ADU Design
ADU Design is the process of shaping your accessory dwelling unit’s layout, exterior appearance, and interior finish so the space works for the people living in it and fits the look of your home and street. In San Diego, good ADU design also means working with local height limits, coastal overlay rules, and neighborhood character review in some areas. A design-focused ADU build typically adds $15,000 to $40,000 in design and finish upgrades on top of the base construction cost, and the right design choices can add tens of thousands in rental value over time. We integrate ADU design with your plans and budget from day one, using materials from brands like James Hardie for durable, low-maintenance siding.
Design Features That Pay Back
Private entrances, sound isolation from the main house, and durable finishes all raise the rent you can charge. In San Diego’s climate, outdoor space is nearly as valuable as indoor; we design ADUs with patios and side yards that make a small unit feel much larger. Every design decision gets priced in writing so you can choose what’s worth it.
Matching Your Main House
Your ADU should look like it belongs on your property, not like a box dropped in the yard. We match rooflines, siding profiles, and paint palettes where possible, and we’ll tell you honestly where a slight style variation looks better. The result is a unit that your neighbors won’t object to, which matters at the permit counter in some San Diego neighborhoods.
Backyard ADU
A Backyard ADU is exactly what it sounds like: a detached accessory dwelling unit built in the rear yard of your San Diego property, typically replacing unused lawn space, an old shed, or a pool that’s become more maintenance than it’s worth. This is the most popular ADU type in San Diego because backyards here are famously underused, and a well-built backyard unit can rent for $2,200 to $3,200 per month in many neighborhoods. A backyard ADU in San Diego typically costs $220,000 to $450,000 depending on utilities distance, grading, and finish level. We’ve built backyard ADUs from National City ADU Builders up to Solana Beach, and each one started with the same written price commitment.
From Old Shed to Income Property
If you have a Tuff Shed or similar structure taking up space, don’t assume it needs to be demolished. We can assess whether the existing slab and framing can support a conversion, and we’ll give you numbers for both reuse and replacement. Sometimes keeping the existing pad saves $10,000 or more in site work.
Backyard Layouts for Narrow Lots
San Diego has plenty of lots that are deep and narrow, and a standard rectangular ADU doesn’t always fit. We work with compact floor plans, sloping sites, and side-yard placements to maximize usable square footage. Your written quote will reflect the actual layout we draw for your specific lot, not a stock plan forced onto your property.
Brands We Service
We install and finish units from Boxabl, the Nevada-based manufacturer known for folding, transportable home modules. A Boxabl Casita requires specific site prep and utility hookups, which we handle from foundation pour to furniture-ready interior. Our crew has completed multiple Boxabl installations in San Diego and knows how to coordinate delivery, crane placement, and final connection on a tight timeline.
We also work with Plant Prefab, a Southern California builder known for high-quality panelized and modular construction. Plant Prefab units favor clean lines and energy-efficient envelopes, and we integrate their panel systems with your site-built foundation, garage, or addition. For hard-wearing coastal siding and trim, we use James Hardie fiber cement products, which hold up to San Diego’s marine layer, salt air, and intense summer sun far better than wood or vinyl. Whether you have a Boxabl, a Plant Prefab unit, or any other make, we can help.
Signs You Need a Pro Right Now
- Your garage is full of stuff you never use. That’s not a storage problem; it’s a sign your garage is the fastest, most cost-effective ADU candidate on your property. Converting it into a legal JADU or ADU adds rentable square footage without expanding the footprint of your home.
- You’re turning down family or rental income because there’s no space. Whether it’s aging parents or a steady tenant, the demand for San Diego housing is relentless. Every month without a unit is income you won’t get back, and construction prices have not waited for the market to cool.
- You’ve asked other contractors for a price and gotten an answer like “let’s see how it goes.” That’s not an estimate; it’s an open checkbook. A written price before work starts is the minimum standard at Lodgewick ADU San Diego, and it’s part of The Kingswell Guarantee.
- Your backyard is a liability, not an asset. Pool demolition, dead lawn, leaning fence. We can turn that underused rear yard into a finished dwelling that pays you back monthly. In San Diego’s rental market, a quality backyard ADU often pays for its own construction within seven to ten years.
- You’re thinking about an ADU but worried about permitting. That worry is valid: the City of San Diego has specific ADU requirements, and a botched permit application can add months. We manage the permitting process from start to finish, with inspections scheduled and passed before you’re asked to pay another cent.
Our Process, Step by Step
- 1
Site walk and honest conversation. Russ Delmar or a senior member of our team comes to your property, walks the yard with you, and listens to what you’re trying to accomplish. We measure, photograph, and take notes on access, slope, existing utilities, and anything else that will affect cost. You get a plain-English explanation of your options, not a sales pitch.
- 2
Written plan and written price. We produce a preliminary design and a detailed, line-item price in writing. This number includes plans, permits, materials, labor, and our overhead, with no “allowance” games that balloon later. You take time to review it; we don’t push for a signature on the spot.
- 3
Permits pulled and inspections scheduled. We submit your ADU plans to the City of San Diego and manage every comment, revision, and resubmittal until the permit is issued. You won’t have to call any city department or decipher a correction notice.
- 4
Construction with a real schedule. Your crew arrives in the window we gave you, in uniform, background-checked, and ready to work. The job site is left clean at the end of every day. If anything changes on-site, we talk to you about it before proceeding, never after.
- 5
Final walkthrough and written guarantee. We walk the finished ADU with you, head to toe, and fix anything you flag before sign-off. Your 365-Day Done Right Promise goes in writing, covering the work free of charge if anything fails within the warranty period. A live person answers your call at (619) 376-2760, 24/7.
How Much Does an ADU Cost in San Diego?
A typical garage conversion or JADU in San Diego runs $90,000 to $180,000. A detached backyard ADU runs $180,000 to $450,000. Attached ADUs and larger two-bedroom units land in the middle, usually $180,000 to $320,000, depending on square footage and the condition of the existing structure. Prefab units from brands like Boxabl or Plant Prefab often fall at the lower end of the detached range because the factory build eliminates framing and weather delays.
What Affects the Price
- Site conditions: slope, access for equipment, distance from utility connections, and soil quality all affect cost. A flat lot in Poway is cheaper to build on than a canyon-edge lot in Normal Heights.
- Size and layout: a 400-square-foot JADU costs far less than a 1,000-square-foot two-bedroom detached unit. Count every square foot honestly.
- Finish level: builder-grade cabinets, flooring, and fixtures can save $20,000 to $40,000 compared to custom cabinetry and higher-end finishes.
- Permit and plan complexity: coastal zones, historical districts, and sites with existing code issues add review time and plan costs.
The best way to avoid overpaying is to get a written line-item quote that names every cost up front. Any contractor who won’t put their price in writing before work starts is planning to change it later. Our free estimate includes the site walk, the plan discussion, and the written price. Call (619) 376-2760 to schedule yours.
Our Service Area Near San Diego
Lodgewick ADU San Diego builds accessory dwelling units, garage conversions, and home additions across the greater San Diego area. We regularly work in neighborhoods from Chula Vista to La Mesa, plus Poway, Imperial Beach, Coronado, Solana Beach, Winter Gardens, Rancho San Diego, National City, Lemon Grove, and La Presa. Most site walks are scheduled within a few days of your call. If you’re in San Diego County and considering an ADU, chances are we’re already building nearby.
Serving San Diego, CA - Our Local Coverage Area
We’re based in the San Diego 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 About ADU Builders in San Diego
An ADU builder is a construction company that specializes in accessory dwelling units: detached backyard cottages, garage conversions, JADUs, and attached suites. They handle the design, permitting, building, and final inspection of your additional unit. Lodgewick ADU San Diego is that specialist, and we’ve focused on ADUs in San Diego since 2010.
Plan to budget 8 to 14 months from first site walk to final inspection for a detached ADU. Garage conversions and JADUs usually run 5 to 9 months because they leverage existing structure and utilities. Permitting at the City of San Diego is often the longest single phase, and we keep it moving from day one. Call (619) 376-2760 and we’ll give you a realistic schedule for your specific property.
Expect to spend $180,000 to $450,000 for a detached backyard ADU in San Diego, and $90,000 to $180,000 for a JADU or garage conversion. The two biggest cost drivers are square footage and site conditions. We provide a written price before any work starts, and that number does not change unless you change the scope. Call (619) 376-2760 to schedule a free estimate.
Yes. We install and finish Boxabl units and Plant Prefab systems regularly in San Diego. Both brands require specific site preparation and utility connections, which we handle in-house to the manufacturer’s spec. We also build with James Hardie siding for durability in San Diego’s coastal climate.
We are not emergency roofing or plumbing contractors, but we do respond to urgent issues on ADUs we’ve built or on active construction sites where our work is underway. A live person answers our phones 24 hours a day, 7 days a week, at (619) 376-2760, so you can always reach someone who knows your project.
Every Lodgewick ADU project is covered by the 365-Day Done Right Promise. If anything on our work fails within 365 days of completion, we come back and fix it free of charge. That promise is written, signed, and included before the first day of construction.
Start by making a list of how you plan to use the unit: rental, family, office, or some mix. Then gather any existing survey documents or site plans you have, and note anything unusual about your yard like drainage issues, old trees, or easements. After that, call us at (619) 376-2760 for a free site walk. We’ll handle the rest, starting with a written price.
Schedule Your ADU Builders Service in San Diego Today
You deserve a written price, a real schedule, and a guarantee in writing before any work begins. That’s The Kingswell Guarantee, and it’s how we’ve operated since 2010. Call (619) 376-2760 to schedule your free, no-obligation ADU estimate in San Diego. We’ll walk your property, answer every question, and put the numbers in writing.
Written by Russ Delmar, Owner at Lodgewick ADU San Diego, serving San Diego since 2010.
