Plan a room addition, second story, primary suite, or expanded living space with one San Diego design-build team. Lars coordinates architecture, structural planning, permitting, selections, and construction so the new square footage feels connected to the home you already love.
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Whether you’re planning a room addition, second-story addition, or expanded living space, Lars brings architecture, structural planning, permitting, selections, and construction together under one roof.
We design around your home’s existing layout, structure, roofline, and style so the new space feels intentional, functions naturally, and supports the way you live.
Ground-Floor Living Space
A ground-floor room addition can create the bedroom, office, family room, or private suite your home is missing while keeping everyday living connected on one level. The right plan begins with how the new space should function, where it can fit on the lot, and how it will join the existing home.
Add a bedroom, office, family room, playroom, studio, or flexible space based on how your household needs to live now and in the future. Placement, circulation, daylight, storage, and access to shared areas shape whether the room feels like a natural part of the floor plan.
A master bedroom addition can become a complete primary suite with a private bathroom, walk-in closet, custom storage, lighting, ventilation, and quieter separation from shared living areas. Planning the bedroom, bathroom, and closet together creates a more comfortable and cohesive retreat.
Foundation, roofline, exterior materials, windows, plumbing, electrical, HVAC, waterproofing, and finish transitions all need to align with the existing home. Lars coordinates architecture, interior design, engineering, permits, selections, and construction so the addition feels intentional rather than tacked on.
Building Up
Building up can create substantial new living space while preserving more of the yard—but only when the existing home, lot, and long-term living needs support it.
A second-story addition can add bedrooms, a primary suite, bathrooms, an office, or flexible family space without extending the ground-floor footprint. The design must connect the new level to the home below through a well-planned staircase, roofline, exterior, and building systems.
Before design moves forward, structural engineering evaluates the existing foundation, framing, walls, roof, and load paths to determine whether they can support another level and where reinforcement may be needed. Plumbing, electrical, HVAC, waterproofing, Title 24, and permitting also become part of the plan.
Building up may be the better fit when the lot is constrained, preserving yard space matters, or you need substantial square footage. A ground-floor addition may make more sense when the lot has room, single-level living is a priority, or adding stairs would work against the household’s needs. Zoning, site conditions, structure, budget, and long-term plans determine the right direction.
Connected Multigenerational Living
An in-law suite addition creates private, comfortable space for family while remaining connected to the main home. It can support aging parents, adult children, long-term guests, or changing accessibility needs without creating a separate household.
Depending on your family’s needs, the addition may include a bedroom, accessible bathroom, sitting area, storage, and a convenient connection to shared kitchen and living spaces. The layout should balance privacy with easy access to the rest of the home.
Entry paths, door widths, bathroom clearances, lighting, sound control, temperature control, and future mobility deserve early attention. Lars coordinates the addition’s architecture, structure, systems, finishes, permits, and construction as one design-build scope.
An in-law suite is an attached addition that remains connected to the main home and functions as part of the household. If you want a separate structure with its own kitchen, bathroom, entrance, and independent living functions, explore our ADU builders page.
Adding square footage is one of the most complex remodeling projects you can undertake. Our On-Time Guarantee means your San Diego home addition comes with a firm completion date — and a team accountable for hitting it.
Built into the process, not promised after the fact.
94%
Planning, pricing, and scope control under one roof.
35+
A local team that understands homes, permits, and expectations here.
1,200+
A repeatable design-build system refined across decades.
Testimonials
See What Happy Clients Are Saying About Us
We just received the closing book for the project we had Lars do, and this is just one more example of the detail and professionalism that was displayed every step of the way (the book contains all product information, warranties, selections, permits, etc that we can hand off to buyers if we ever move). The process started with a free design consultation with Seth Larson and John Klacka, who were such a pleasure to work with, and who seemed genuinely excited to work within the somewhat unusual parameters of our project (a second story on our detached garage to add an artist’s studio, storage, and guest quarters). Next, we had the pleasure of working with Chih, who helped us with our selections of flooring, doors, hardware, colors, fixtures, etc. She was so attentive to our tastes and preferences; the process was made that much easier.
Our project manager was Brian, after working with him closely for a good six months, I have to say that he will be missed!!! He was very patient, attentive, and prompt at addressing any questions or concerns, and handled requests for changes gracefully. He also likes dogs, which is important to us 🙂
As others have noted, it’s very reassuring to know that Lars doesn’t vanish with the end of the project, but will be there to help with warranties, etc. Finally, the project came in on time and as budgeted so there were never any nasty surprises or hidden costs. This company is of the highest quality and delivers peace of mind, which in my book is priceless.
We have had the pleasure of working with LARS for the addition of an attached ADU at our home and a half bath in another location. Our Project Consultant, Ken, is an excellent communicator and walked us through all aspects of the project, including contact with our HOA and SD city for plan approvals. Saif, created the intricate plans based on our preferences, as well as a virtual rendering of the finished product. Erica, the interior design consultant, “”got me”” when it came to all the interior finishes, from counters and tile to fixtures and paint colors. Our detailed on site Project Manager, Jon, kept a tight schedule to keep the project moving along. He made sure the work area was kept tidy and existing elements of our home were protected. We had used Lars in the past and are very happy we came back! We highly recommend using Lars Remodeling and Design!
I would highly recommend the Lars team. The whole team is highly professional. We hired Lars for the addition of a bedroom and full bathroom to our house. We had some issues with our HOA regarding the addition, and they have been with us, attended HOA meetings to address any architectural questions for the HOA, and came up with a backup plan, as the original plan did not go through. Jennifer was our project manager, and she gave us wonderful ideas on how we could plan the addition in the limited space we had. Kudos to her design skills :). Dwayne was our site manager, and he went above and beyond to address any concerns or questions we had regarding the construction. They looked after all the materials and paperwork for us. We are totally happy with our new addition. 5 stars all the way!!!
My husband and I wanted to build a room addition/casita onto our eighteen-year-old home that looked like it was “originally built” with the house. We contracted with Lars and were especially impressed with the beginning design phase of our project (using architectural software that enabled us to see our project conceptually from all angles). They really worked with us to incorporate our ideas and wishes. Lars included certain design elements in the addition that repeated those in the existing house, thus making it look like original construction. The project stayed on schedule, even when some materials were backordered, with other construction trades filling in when possible. Our project manager, Jeff, was very attentive and kept us informed as to upcoming building activities. The project was completed in a timely manner and we couldn’t be happier with the outcome. We would certainly refer Lars to anyone who is considering home remodeling.
This is our second project with Lars. This time it was a small room (bedroom) addition over the garage. Extremely satisfied with the process from start to finish. We had a fixed budget and asked them to show what could be done within those constraints. After discussing our specific “wants and needs” with us, they developed a couple of different design options that fit within the budget. As with any renovation to an existing home there are always going to be some unknowns to consider. For example: Is this a load-bearing wall?, Can the existing foundation support the weight of a second floor addition? I was pleased that their cost estimates planned for the worst case and gave us a credit if it turned out the extra expense was not needed. There were a couple of necessary change orders that did pop up, but our overall costs stayed within the initial cost estimate. Our project manager, Duane Cruse was superb. Kept the project moving along, masterfully shifting the different trades in and out as needed to make sure there were no “down days” due to bad weather or other factors. We actually finished the project a couple of weeks ahead of schedule. Quality of workmanship was excellent. Particularly impressed with the framers, plumbers, roofers, cabinet-makers and electricians. Lots of compliments from neighbors and friends about the impressive results and timeliness of the project.
We selected Lars to remodel an entire floor of our house as an ADU for our family. Throughout the process, our project consultant Jen Cavanaugh was a guide we could rely on. Her professionalism and experience were extremely helpful from the very beginning planning phase all the way through the last few items on our punch list. She sent samples when we couldn’t come to the showroom, and was open to FaceTime and online meetings before everyone hopped on Zoom. She has even supported us with a few minor issues we’ve found since using the remodeled space.
Jen and Matt with appliances and fixtures really helped keep the focus of our project on age-proofing the space for future use by “grandma and grandpa.”
We appreciated the long track record of reliability that came with a firm like LARS, and that our project consultant helped us navigate everything in one place: design, permit, and build. There were no long pauses in our project, even during the pandemic.
Working with Lars was a dream come true!! We’ve lived in our house for 20 years and after having 2 growing boys our house, specifically the upstairs area, was not meeting our needs. We were literally in a “”Love it or List it”” moment. But we love our neighborhood, love our neighbors and the school our boys attend. So we went the tough route of doing a remodel. In the end we have an expanded master suite that is SWEET!! I could not have dreamed of a more fabulous master bath and my own dreamy dressing room!! My husband got his own closet and we both gained the privacy and personal space we desperately needed.
The customer service with Lars is unparalleled! Ken was our project consultant with a fabulous eye for design and functionality. He guided us effortlessly through all the steps so that we knew exactly what was to be expected along the way. Jessica helped us pick out all our materials and colors and we had a blast shopping for our new space.
Once the construction phase started we were paired with Bobby as our project manager. He was amazing! As with any construction project issues came up and he handled them quickly and efficiently. We were in the best of hands with Bobby! We never had to worry about any issues with any of the trades. Bobby handled them all. He was probably working on at least 4 other projects at the same time as ours but we always felt like we were his number one priority! That’s the feeling you get when you work with Lars. They are all such a pleasure to work with. When you’re changing your living space so dramatically and spending a pretty penny to do it you really want to do it with a company you can trust and rely on. That’s exactly what we got and we are beyond thrilled with our new space!!
Lars added a family room to our home last summer, and the entire process was seamless from start to finish. Having previously used a different company for a bathroom remodel, I was aware that not all companies operate the same way. However, Lars exceeded our expectations. Throughout the design phase, they listened to our needs and allowed us to take our time with each adjustment to ensure the room was exactly what we envisioned. The pricing was transparent and helped us stay within our budget while prioritizing our design choices. We appreciated being able to track every aspect of the project through the design app they used, which was incredibly helpful.
The standout element of the project was Shane, our Project Manager. He visited our home daily to ensure that every aspect of the construction met the ‘Lars Standard’. He kept the project moving on track, and it was finished under the projected time-frame. Shane was never rushed or hurried with us and communicated clearly about what each week would entail and was always just a text or call away whenever we had questions.
Lars just finished my gorgeous new master bedroom suite in Rancho Penasquitos. I can’t say enough about what a wonderful experience this process was for me and my family. Brandon and Jeff felt like family from the beginning. Very approachable at any time for any questions that popped into my head. Every single sub they used was extremely kind and friendly and helpful and respectful. The property was left pristine each day when the workers left and the project was finished ahead of schedule. I know this all sounds too good to be true, but everything was coordinated like a well-oiled machine, and we are thrilled with the results!
With construction, there are so many variables that can happen along the way. There really is no way to predict every obstacle that can come up. It’s HOW the company handles these issues that are important. I could tell from working with them that they are very aware that there is always room for improvement. They want to learn from each experience in order to improve the next one. They tell you up front what their expectations are for themselves, their employees and their sub contractors and ask that you let them know if anything happens that are not within these expectations. Their goal truly is for their customer to be happy and my project manager, Jeff, made that very clear to me throughout the process. Thanks so much to all of you at Lars. I will recommend you to everyone I know!!! xo
before + after [ Slide the arrow left to right to view the transformation. ]
The Lars Experience
Since 1991, Lars Remodeling & Design has helped San Diego homeowners add space without losing the character of the home they already love.
Our design-build team coordinates architecture, interior design, engineering, permitting, selections, and construction from the first conversation through the final walkthrough. Instead of managing separate architects, designers, engineers, and contractors, you have one accountable team guiding the decisions together.
Lars offers more than home additions. From ADUs to whole‑house updates, we’re San Diego’s all‑in‑one home remodeling resource.
Lars Remodeling & Design is also your first choice for efficient home remodels across San Diego. We offer a wide selection of high-quality remodeling services, ranging from stunning room additions in San Diego to the finest San Diego kitchen remodeling to completely independent accessory dwelling units.
You can rely on our dependable remodeling services no matter where you are in San Diego. We’re the leading home remodeling & design company in Solana Beach, and we also offer tailored home remodeling in Carmel Valley. What’s more, we also provide custom remodeling in Poway as well as the favorite Point Loma home remodeling & design. Don’t hesitate to count on us to make your remodeling dreams come true with expertise and skill. Reach out to us today and see why we’re the best!
San Diego Addition Investment Planning
A full design-build home addition in San Diego typically starts at $100,000 and can exceed $400,000 depending on scope. These are complete design-build planning ranges, not construction-only estimates. They account for architecture, structural engineering, construction drawings, permit preparation and coordination, interior design and selections, project management, and construction. Final cost depends on project scope, structural complexity, site conditions, square footage, and finish level.
| Addition Scope | Typical Investment Range | What It Includes |
|---|---|---|
| In-Law Suite Addition | $150,000–$200,000+ | An attached, connected suite with a private living area, bathroom, and kitchenette. Unlike a detached ADU, it is designed as part of the primary home for comfortable multigenerational living. |
| Primary Suite Addition | $175,000–$400,000+ | A private bedroom suite with its own bathroom, closet, custom storage, lighting, plumbing, ventilation, and interior design selections planned as one complete space. |
| Second-Story Addition | $200,000–$400,000+ | Converting a single-story San Diego home to two stories requires structural engineering, temporary roof support, a new staircase, roof and utility integration, and full permitting. |
| Single-Room Addition | $175,000–$250,000+ | A new bedroom, home office, or family room with its own foundation, framing, roofing, electrical work, and HVAC tie-in coordinated with the existing home. |
| Bump-Out / Small Addition | $100,000–$130,000+ | A compact expansion that still needs design, drawings, structural review, permits, waterproofing, exterior tie-ins, and finish coordination. |
These ranges are planning references, not estimates for a specific project. Every property is different, so accurate pricing requires feasibility review, design scope, site conditions, and proper planning before numbers should be trusted.
Scope, Structure & Site Conditions
The biggest variables are whether the addition requires a new foundation, the complexity of tying new structure into the existing home, roofing type, site access, and the extent of HVAC, electrical, and plumbing extensions. Interior finish selections also affect the final investment.
Lars manages architecture, engineering, permitting, interior design, and construction under one contract. You work with one accountable team from design approval through move-in.
Paying For The Project
Most San Diego homeowners fund an addition through home equity — a home equity loan or HELOC — or through a cash-out refinance, a renovation loan such as an FHA 203(k) or Fannie Mae HomeStyle, or contractor-arranged financing. Many combine savings with one of these rather than using a single source.
The practical detail people miss is timing: lenders release renovation funds on a draw schedule tied to construction milestones, so the financing structure and the build schedule need to be planned together. Settling scope and budget before construction starts is what keeps draws and payments aligned.
Lars is a design-build contractor, not a lender, and does not provide financial advice. Compare terms with your lender or financial advisor before locking in a scope.
Before You Compare Addition Quotes
If a quote answers "separate" or "TBD" to more than one of these questions, the all-in number may land close to, or above, a bundled design-build proposal after the missing pieces surface.
CSLB recommends a detailed written contract with scope, payment schedule, permit responsibility, completion timing, change-order terms, and license information. Review CSLB contract guidance.
Addition Types
Every addition type affects the home differently. Lars helps you compare footprint, structure, privacy, utilities, finishes, approval path, and long-term value before you commit to a design direction.
Considering a separate living unit? See our ADU builders. If the project affects most of the home, compare whole-house remodeling. If the new space includes a bath, review our bathroom remodeling planning.
Building in North County? See room additions in Encinitas.
Add a bedroom, office, family room, studio, or flexible living space that feels original to the home instead of tacked on.
Add major square footage without sacrificing yard area, with structural engineering, stairs, roof integration, and load-path planning handled early.
Create a private retreat with bedroom, bath, closet, storage, lighting, and premium finish selections designed as one complete experience.
A full design-build bump-out addition typically runs $100,000–$130,000+ and can expand a kitchen, dining area, bath, or living space when the existing footprint needs more breathing room but a full wing is not the goal.
Plan private, comfortable space for family with thoughtful access, privacy, aging-in-place details, and a clear distinction from a rentable ADU.
Open the heart of the home with a larger kitchen, gathering space, better indoor-outdoor connection, and coordinated premium selections.
Permits & Structural Requirements
Permits, engineering, and zoning are not afterthoughts on an addition. They shape what can be built, how long design review may take, and whether a ground-floor addition, second story, or alternate scope makes the most sense.
Useful official references: DSD Residential Addition/Remodel, construction permit fee schedule, residential base-zone regulations, coastal development permit rules, and California Energy Code.
Room additions and remodel additions require project-specific plans submitted for review. Plan check can take several weeks, and complex additions should be planned with more review time.
Second-story additions need engineering review of the existing foundation, framing, roof, and load paths before design assumptions become construction problems.
Setbacks and height limits vary by zone. The City RS tables include different front, side, rear, height, FAR, and lot-coverage rules, so zoning is verified before drawings are finalized.
Coastal Overlay Zone homes, HOAs, canyon or hillside lots, and Title 24 energy requirements can affect scope, timing, solar PV considerations, and approval path.
Larger additions, second stories, and hillside conditions may require foundation investigation, soils input, and structural details before final pricing and drawings are complete.
Additions often affect plumbing, electrical, HVAC, roof drainage, waterproofing, and inspection sequencing, so those systems are planned before construction starts.
Why Full Design-Build Matters
Additions routinely require architecture, structural engineering, permitting, Title 24, finish selections, construction sequencing, and inspection coordination. Lars keeps those decisions under one roof so the budget and design evolve together instead of being handed from one vendor to the next.
Best fit for homeowners who need:
Floor plans, elevations, construction drawings, structural coordination, and permit strategy stay connected to the build budget from the start.
Lars plans cabinetry, tile, lighting, fixtures, surfaces, appliances, flooring, hardware, and finish details before construction begins.
Additions touch foundations, framing, rooflines, utilities, waterproofing, Title 24, inspections, and city comments. We coordinate those handoffs in-house.
Our team understands older homes, coastal neighborhoods, canyon lots, second-story constraints, and the expectations that come with premium additions.
Review CSLB License #616035 through the official California license lookup before signing a home addition contract.
You are not left coordinating a separate architect, engineer, designer, permit consultant, and contractor. One Lars team owns the path.
Verify contractor license details through the official CSLB license check. Lars Remodeling & Design CSLB License #616035.
Room Addition Process
A room addition needs more than square footage. Lars connects design, structural review, permits, selections, site work, and construction management so the new space feels intentional, code-ready, and integrated with the home.
We start with the room you need, how it should connect to the existing home, your investment range, timing, privacy needs, and the problems the addition must solve.
Our team reviews structure, rooflines, foundation conditions, setbacks, utilities, drainage, HOA or coastal constraints, and likely permit requirements before design moves too far.
Lars develops the addition plan, exterior tie-ins, structural direction, preliminary selections, and budget alignment so the new room is planned as part of the original home.
We coordinate construction drawings, plan check, Title 24, engineering details, finish selections, schedule planning, and pre-construction decisions before the build begins.
A project manager coordinates foundation, framing, roofing, waterproofing, MEP tie-ins, inspections, interior finishes, closeout, and final walkthrough.
These projects show the range of room additions, second-story work, bath additions, and whole-home coordination that make addition planning more complex than a simple square-foot calculation.
Not sure which service fits your next step? Explore related Lars design-build services to see how kitchens, baths, additions, ADUs, outdoor living spaces, custom homes, and whole-home remodels can be planned together under one accountable team.
Our team designs and builds stylish, functional ADUs and in-law suites that maximize space, elevate comfort, and increase property value, seamlessly managed from initial concept to final inspection.
From the ground up, we build custom homes that reflect your lifestyle, goals, and personal design preferences; crafted with precision and built to last.
Our award-winning team offers complete home remodeling in San Diego, CA, that reinvents your living space. We manage everything from permits to paint colors, creating flowing designs that make your house feel fresh, functional, and uniquely yours.
Our home remodeling San Diego experts can remodel your kitchen into a stunning and functional space where your family gathers and memories form. From custom cabinets to perfect lighting, we handle every detail that turns ordinary kitchens into extraordinary ones.
Our home remodeling San Diego experts transform bathrooms into beautiful, functional spaces designed for comfort, relaxation, and everyday use. Whether you’re updating a guest bath or creating a spa-inspired master bathroom, our bathroom remodeling contractors handle every detail—from custom vanities and tile to lighting, fixtures, and finishes.
In San Diego’s ideal climate, our home remodeling San Diego experts create outdoor retreats that feel like natural room extensions. We design entertaining spaces, cooking areas, and relaxation zones that maximize your outdoor living space.
Our San Diego design-build remodeling services bring design, planning, and construction together under one roof. From kitchen or bath to whole home remodels and additions, our in-house team guides every step of the process to create a cohesive, well-planned remodel built around your home, lifestyle, and long-term goals.
From new bedrooms and family rooms to primary suite expansions and second-story additions, Lars Remodeling & Design helps San Diego homeowners plan room additions with architecture, engineering coordination, permitting, selections, and construction under one accountable design-build team.
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