ADU Construction
ADU Construction in Redwood City & Silicon Valley
Add a self-contained home to your property with a custom ADU designed for family, guests, or rental income.
Accessory Dwelling Units (ADUs) are one of the smartest ways to add livable space and long-term value to your property in today’s California housing market. Whether you call it a granny flat, in-law suite, backyard cottage, or guest house, an ADU provides a fully self-contained home right on your lot. Many clients use ADUs for aging parents, adult children, visiting guests, or rental income that helps offset their mortgage. Calwest Builders offers turnkey ADU construction—design, permits, and build—throughout Redwood City, Menlo Park, Atherton, Woodside, and nearby Silicon Valley communities, with a strong understanding of current state and local ADU regulations.
ADU Design & Planning
Tailored to Your Needs
Every ADU project begins with a clear understanding of its purpose. We start by asking who will live there and how they’ll use the space—long-term family, short-term guests, or tenants—then design accordingly. That might mean including aging-in-place features for parents, built-in desks and storage for a home office, or an efficient layout optimized for rental appeal. Bedroom count, kitchen configuration, privacy, and outdoor connections are all tailored to your goals and your property’s unique characteristics.
Maximizing Small Spaces
ADUs are typically modest in size, but good design can make them feel open and airy. We use strategies such as open-plan living, well-placed windows, vaulted ceilings, and built-in storage to maximize every square foot. Thoughtful kitchen layouts, multi-functional furniture nooks, and integrated outdoor patios or decks create a sense of generous living despite the smaller footprint. Our goal is to deliver an ADU that feels like a complete home, not an afterthought tucked into the yard.
Navigating Regulations
Statewide laws have made ADUs more accessible than ever, but each city still maintains its own rules around setbacks, maximum size, height, and parking. We stay current on ADU guidelines for Redwood City, Menlo Park, Atherton, Woodside, and other Peninsula jurisdictions. During planning, we analyze your lot and local ordinances to determine feasible size, placement, and configuration. By designing with compliance in mind from day one, we help your ADU move smoothly through review and permitting.
ADU Construction Services
Foundations & Utilities
An ADU is a standalone structure that requires its own foundation and carefully planned utility connections. We handle all site preparation, excavation, and foundation work—whether your lot is flat or sloped like many in Emerald Hills. Utilities are designed and installed to meet code: sewer ties, water lines, electrical service, and gas if needed. We can help you decide whether to share meters with the main house or pursue separate metering if you plan to rent the unit.
Building & Exterior Finishing
From framing and roofing to windows and exterior cladding, we build ADUs to the same standards as custom homes. Exterior materials and details can either match your main residence or intentionally complement it with a related but distinct style. We focus on creating a tight, energy-efficient building envelope with proper insulation, high-performance windows and doors, and durable finishes that withstand the local climate. The result is a backyard home that looks and feels substantial—not temporary or flimsy.
Interiors & Amenities
Inside, ADUs may be compact, but amenities don’t have to be. We incorporate full kitchens or kitchenettes, comfortable living areas, well-proportioned bedrooms, and attractive bathrooms, often with features like curbless showers for accessibility. In-unit laundry, smart thermostats, and thoughtful storage solutions make the space truly livable over the long term. Whether you’re planning a high-end guest suite or a rental that commands premium rates, we design the interior to meet those expectations.
Custom vs. Prefabricated Approaches
While prefabricated ADUs exist, our focus is on custom-built or highly tailored projects that integrate beautifully with your property. Custom construction offers greater flexibility with layout, finishes, and site adaptation, especially on irregular or sloped lots. If you’re considering a prefab option, we can discuss pros and cons and, where appropriate, assist with site work and integration. Most of our clients choose a custom design-build ADU for superior fit, finish, and long-term value.
Why Choose Calwest for Your ADU Project
One-Stop Design-Build Partner
For many homeowners, an ADU is their first experience with development, and the process can feel overwhelming. Calwest simplifies it by serving as a single partner from feasibility and concept through final inspection. We coordinate design, engineering, permit submittals, construction, and finishing details so you don’t have to manage a long list of separate consultants and contractors.
Quality, Comfort & Long-Term Value
We treat every ADU like a small custom home, not a secondary project. That means building for comfort—quiet, well-insulated walls, efficient heating and cooling, and durable finishes that hold up over time. Whether you plan to live in the ADU yourself, host family, or rent it out, the quality of construction will support long-term enjoyment and strong resale value. In many cases, an ADU can meaningfully increase property value and create an income stream that helps offset project costs.
Local Expertise & Permitting Know-How
Because ADU rules continue to evolve, local experience matters. We stay current on the latest state and municipal guidelines, including streamlined permit procedures, parking waivers, and by-right approvals where applicable. Our familiarity with city staff, submittal requirements, and review timelines helps keep your project moving and minimizes unnecessary delays.
Personalized Design that Fits Your Property
No two lots or family situations are exactly alike. We position and design your ADU with privacy, views, sunlight, and circulation in mind—both for the main home and the new unit. Whether you prefer an ADU that closely matches the main house or a fresh architectural statement, we’ll ensure it feels intentionally integrated into your property.
Unlock Your Property’s Potential
Ready to explore what an ADU could do for your family and your property? Contact Calwest Builders to schedule an ADU consultation. We’ll assess your lot, discuss your goals, and guide you through the next steps toward a high-quality, self-contained home in your own backyard. With housing at a premium in Silicon Valley, a well-designed ADU can be both a practical solution and a smart long-term investment.
How much does it cost to build an ADU?
ADU costs depend on size, design complexity, and level of finish, but in Silicon Valley a smaller studio or one-bedroom ADU often starts in the mid hundreds of thousands, with larger two-bedroom units and high-end finishes scaling higher. These figures typically include foundation, utilities, structure, and interior finishes. During our feasibility and design process, we prepare a detailed budget breakdown so you understand the investment and can adjust scope and features as needed.
What are the size limits for ADUs in this area?
California law allows ADUs up to certain maximums, often in the 800–1200 square foot range, but exact limits depend on your city, zoning, and lot configuration. Some jurisdictions also offer flexibility for smaller “junior” ADUs within the main home. As part of our initial analysis, we’ll review current local rules and your specific property to determine the maximum allowable size and the most practical layout options.
Do ADUs need separate utilities or can they share with the main house?
ADUs can often share some utilities with the primary residence, but each project is unique. In some cases, we upgrade the main electrical panel and tie into existing services; in others, owners prefer separate meters to simplify billing for a rental. Sewer and water connections are designed according to local code and site conditions. We’ll walk you through the options and recommend an approach that balances cost, convenience, and long-term plans.
How long does it take to build an ADU?
ADU projects typically move faster than large home additions or full-home remodels, but still involve design, permits, and construction. Design and approvals might take a few months depending on the city, and construction can often be completed in roughly 4–6 months once started, depending on complexity and site conditions. We’ll outline an expected timeline during the early stages and keep you informed as each milestone is reached.
Will an ADU increase my property taxes?
Adding an ADU generally increases your property’s assessed value, and with that, your annual property taxes. However, the additional living space and potential rental income often more than offset this change over time. We encourage you to discuss specific tax implications with your financial or tax advisor, and we can provide general project cost information to support those conversations.
Can you design the ADU to match my home?
Absolutely. Many homeowners prefer ADUs that look like they were built alongside the main house, with matching rooflines, siding, and trim details. Others opt for a complementary but distinct style to create visual interest. We’ll explore both options with you and design the ADU so it enhances your overall property, inside and out.
Do I need a garage, or can I convert my existing garage into an ADU?
Garage conversions are a popular way to create an ADU without building entirely from scratch. We can convert attached or detached garages by insulating and finishing the structure, raising or leveling floors as needed, and adding proper plumbing, electrical, and egress. In some cities, you may also be allowed to build a new ADU while maintaining parking solutions, subject to local requirements. We’ll review what’s possible on your lot and help you choose the best path forward.