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About SD3DU & Our Process

  • SD3DU is a residential design-build studio specializing in transforming living spaces. We offer a comprehensive range of services including ADU design and permitting, custom home design, remodels and additions, interior design, and feasibility reports. Our team guides clients through every step, from initial concept to final construction.

  • We specialize in a variety of residential projects, focusing on maximizing property potential. This includes designing and building ADUs (Accessory Dwelling Units), creating custom homes, transforming existing spaces through remodels and additions, and enhancing interiors through design. We also provide zoning research and feasibility studies.

  • SD3DU stands out through our commitment to client collaboration, innovative design solutions, and extensive expertise in both design and construction. We focus on delivering a seamless and personalized experience that enhances everyday living and adds long-term value to your property.

  • The design-build process streamlines your project by combining design and construction services under one contract. At SD3DU, we take a collaborative and client-focused approach. The process includes:

    • Discovery Phase – Understanding your vision and goals.

    • Site Analysis – Documenting existing conditions and zoning constraints.

    • Schematic Design – Generating conceptual ideas and massing models.

    • Design Development – Refining layout, finalizing architectural details, and incorporating engineering estimates.

    • Construction Documents – Creating detailed permit-ready blueprints.

    • Permitting – Navigating regulatory approvals.

    • Bidding or Contractor Selection – Involving the builder early to ensure cost control.

    • Construction & Oversight – Coordinating the build, including inspections.

    • Interior Design – Creating a cohesive final look.
       

    We bring in the contractor early (ideally the one who will build the project) during design to improve accuracy in budgeting and constructibility. Our approach emphasizes transparency, realistic expectations, and a commitment to excellence.

  • Very involved. SD3DU believes in a collaborative design process where your input shapes the final result. We encourage open communication and guide you through design iterations, ensuring your vision is realized at every phase.

  • We value clear and consistent communication. You'll receive regular updates throughout the project and we’ll be available to promptly address questions or concerns. We build strong client relationships through transparency and responsiveness.

Custom Homes, Remodels & Design

  • A good starting point for most projects in San Diego is $400–$500 per square foot. This estimate includes both:

    • Soft Costs – Design, engineering, and permitting.

    • Hard Costs – Construction materials and labor.

    • More complex projects or second-story additions may exceed this range.

  • Costs vary significantly based on the scope, size, complexity, materials, and site conditions. During the design phase, SD3DU provides detailed, project-specific cost estimates so you can make informed decisions.

  • Several factors affect your overall project cost, including:

    • Design complexity

    • Size and layout

    • Site conditions and zoning

    • Material and finish selections

    • Permit and inspection fees

    • Labor and subcontractor rates

    • Unforeseen construction conditions


    SD3DU will walk you through each of these considerations and provide transparent cost breakdowns.

    • Soft Costs include design, architectural and engineering fees, permitting, and utility connections.

    • Hard Costs are physical construction expenses, such as site prep, foundation, framing, electrical, plumbing, roofing, and finishes.


    Soft costs typically range from $30,000–$70,000, while hard costs start around $400 per square foot, depending on project type.

  • Begin with a site analysis and zoning review to understand what can legally be built. SD3DU uses the San Diego Zoning Map and Municipal Code to assess constraints, allowable uses, and potential limitations. A feasibility study includes:

    • Documenting existing site conditions

    • Evaluating zoning, setbacks, and floor area ratio (FAR)

    • Identifying regulatory hurdles (e.g., CDPs, historic reviews)

  • Understanding your lot’s zoning and constraints is essential. SD3DU starts with a feasibility study to determine what is allowed and develop a clear project roadmap based on city regulations and your property’s characteristics.

  • The SD3DU design-build process includes:

    • Site Analysis

    • Schematic Design

    • Design Development

    • Construction Documents

    • Permitting

    • Bidding / Contractor Selection

    • Construction

    • Interior Design

  • Schematic Design is when we explore conceptual ideas and layout options. This phase includes:

    • Massing models

    • Preliminary floor plans

    • Initial spatial planning
       

    It’s the foundation for developing your project vision.

  • In Design Development, we refine the schematic concept through:

    • Finalized floor plans and elevations

    • Structural and mechanical coordination

    • Material selections

    • Engineering input and budget alignment

    Multiple design iterations ensure the concept evolves into a fully developed plan.

  • Construction Documents are detailed plans used for:

    • Permit submittals

    • Bidding

    • Actual construction
       

    They include site plans, floor plans, elevations, electrical and framing layouts, and Title 24 energy reports. Structural engineering may also be included, depending on your project’s needs.

  • Major design changes after this phase may increase costs and extend timelines, so we recommend finalizing your concept earlier in the process. Minor adjustments are still possible.

  • Focus on choosing a clear concept and vision during Schematic Design. Refining that concept through design development will yield the best results and avoid costly late-stage revisions.

  • Prioritize:

    • Natural light

    • Open and efficient layouts

    • Privacy

    • Flow and function

    • Local zoning and FAR limits

    SD3DU balances these considerations with aesthetic goals and site-specific conditions.

  • We recommend:

    • Ductless mechanical systems

    • Quality insulation

    • Energy-efficient windows and doors

    • Solar (where applicable)

    These elements reduce utility bills and increase long-term sustainability.

  • Yes! We offer interior design to ensure a cohesive and stylish final result. We guide selections of finishes, materials, colors, layouts, and furnishings tailored to your taste and lifestyle.

  • Key factors include:

    • Natural and durable materials

    • Consistent, cohesive design language

    • Efficient use of space

    • High-quality finishes that balance form and function

  • Yes. As a design-build studio, we handle:

    • Construction documentation

    • Permit coordination

    • Scheduling inspections

    • Contractor communication (if requested)
       

    Permit processing and construction administration are considered additional services post-permit issuance.

  • We recommend involving a General Contractor early in the design phase to improve cost control and planning. In a Design-Bid-Build scenario, SD3DU can assist with the bidding process, though this may extend your schedule.

  • Hiring a licensed general contractor is strongly recommended for streamlined execution. If you choose to self-manage, SD3DU can offer Construction Administration to oversee compliance with plans.

    • Making layout changes late in the process

    • Underestimating costs

    • Skipping proper permits or planning

    • Choosing unqualified subcontractors

    Early planning and expert guidance help avoid these issues.

  • Yes. Even if you pursue a design-build route, comparing multiple bids helps validate pricing and assess value.

  • Construction timelines vary, but common delays come from:

    • Permitting processes

    • Material availability

    • Subcontractor scheduling

    • Inspection coordination

    For a smoother process, involve experienced professionals and plan thoroughly.

Accessory Dwelling Units (ADUs)

  • An Accessory Dwelling Unit (ADU) is a secondary housing unit built on a single-family or multi-family residential lot. ADUs are independent living spaces with a separate entrance, kitchen, bathroom, and sleeping area. They can be:

    • Detached – Separate from the main home

    • Attached – Connected to the main home

    • Garage Conversions

    • Converted spaces – From attics, basements, or second stories

    Maximum size is 1,200 sq. ft., depending on type and site constraints.

  • A Junior ADU is a smaller unit (150–500 sq. ft.) created within an existing or proposed single-family home. JADUs must share a bathroom with the primary home or have a limited kitchen, and the property owner must reside on-site.

  • ADUs offer many benefits, including:

    • Rental Income – $1,500–$3,500/month in San Diego

    • Increased Property Value

    • Flexible Housing – For family, guests, or caregivers

    • Retirement Planning – A long-term investment

    Affordable Housing Contribution – San Diego offers incentives for affordable ADUs

  • Yes, it’s possible, but the process is complex and depends on local regulations. Contact SD3DU for more information about subdividing and selling.

  • Yes. ADUs can be built in mixed-use developments that include residential units.

  • If your property is in a residential zone (RS, RE, RX, RT, or RM), then yes, you’re allowed to build at least one ADU. Use San Diego’s zoning portal to verify your property’s eligibility.

  • No. San Diego does not require a minimum lot size for ADU construction.

    • Single-Family Lots – 1 ADU + 1 JADU

    • Multi-Family Lots – Multiple ADUs may be allowed using density bonus or affordability incentives

    • ADUs – No, owner occupancy is not required.

    • JADUs – Yes, the property owner must live on-site.

  • Yes. Garage conversions are permitted and even encouraged. Parking replacement is not required when converting a garage into an ADU.

    • Detached ADUs – Up to 1,200 sq. ft.

    • Attached ADUs – Up to 50% of the main home’s size, capped at 1,200 sq. ft.

    • JADUs – Between 150–500 sq. ft.

  • The smallest allowed is 150 sq. ft., which must include sleeping, cooking, and bathing facilities.

  • Yes, but you must comply with local height and Floor Area Ratio (FAR) regulations.

  • ADUs must follow applicable rear, side, and front setback requirements according to your zone. Detached ADUs generally require 4-foot side and rear setbacks.

  • Yes. If you prefer it to be considered “detached,” a 1-inch seismic expansion joint can be added to separate the structures.

  • There are four main ADU types:

    • Detached ADUs – Standalone units

    • Attached ADUs – Built onto the main home

    • Garage Conversions – Cost-effective options

    • Converted Basements/Second Stories – Build up or down instead of out
       

    Each has different costs and design requirements.

  • Rather than maxing out at 1,200 sq. ft., consider function and budget. General guidelines:

    • Studios – < 300 sq. ft.

    • 1-Bedroom – 400–600 sq. ft.

    • 2+ Bedrooms – 700+ sq. ft.
       

    SD3DU helps evaluate the best size based on purpose, site conditions, and ROI.

  • Stick-Built ADU
    ✅ Full customization
    ✅ Seamless integration with main home
    ✅ Higher resale value
    ❌ Longer build time
    ❌ Higher cost
     

    Prefab ADU
    ✅ Faster, factory-built construction
    ✅ Lower upfront cost
    ✅ Less on-site disruption
    ❌ Limited layout flexibility
    ❌ Lower appreciation potential
    ❌ Shipping size restrictions

  • Yes. Repurposed containers are permitted in California. They are cost-effective and sustainable but still require proper insulation, engineering, and code compliance.

  • Yes. All ADUs require a building permit and must comply with city regulations.

  • Permitting may take 8–12 months, depending on project complexity. Streamlined ADU programs may shorten timelines.

  • Some San Diego jurisdictions waive permit fees, but other charges like utility or school fees may still apply. Contact SD3DU for current local fee info.

    • Permit Fees

    • Utility Connection Fees (if adding separate meters)

    • Impact Fees – Waived for ADUs

    • School Fees – May apply for additions >500 sq. ft.

  • If your lot is west of I-5, you may need a CDP—unless your project qualifies for an exemption (e.g., additions under 10% of floor area or certain ADUs).

  • ​No. San Diego does not require additional off-street parking for ADUs.

  • Yes. Flexible configurations such as tandem or front-yard parking are allowed, but often, no parking is required at all.

  • No, but you may choose to add one. Some utility providers may require a separate meter based on usage.

  • If your home exceeds 39 plumbing fixture units, a water meter upgrade may be required.

ADU Investment, Tax Strategy & Leasing

  • ADU costs vary based on type, size, finishes, and site conditions:

    • Detached or Attached ADUs – ~$400 per sq. ft. and up

    • Garage Conversions – ~$300–$350 per sq. ft.

    • Second-Story ADUs – ~$450–$500 per sq. ft.

    These estimates include both soft and hard costs, but your final cost will depend on your choices and property specifics.

  • ADU costs fall into two categories:

    • Soft Costs – Permits, design, engineering, utility connections, typically $30,000–$70,000

    • Hard Costs – Construction, labor, finishes, site prep; usually $400+/sq. ft.
       

    Even if using pre-approved plans, soft costs still apply.

  • Cost-saving strategies include:

    • Use cost-effective materials

    • Minimize plumbing fixture counts

    • Limit additions to under 500 sq. ft. to avoid school fees

    • Keep multi-family ADUs under 1,000 sq. ft. to avoid landscaping regulations

    • Take advantage of affordable housing incentives and regulatory exemptions

    SD3DU can help you design smart and stay on budget.

  • Yes! SD3DU will guide you through:

    • Estimating soft and hard costs

    • Aligning costs with your financing plan

    • Managing construction milestones and cash flow

    • Connecting with preferred lenders and contractors

    We create a clear and realistic financial roadmap to avoid surprises.

  • You have several financing options:

    • Cash-Out Refinance – Replaces your mortgage and pulls equity for construction

    • HELOC (Home Equity Line of Credit) – Flexible, interest-only during draw period

    • Renovation Loans – Funds based on future value of your home

    • Personal Loans – Quick but usually higher interest rates

    The best method depends on your credit, equity, and project timeline.

  • Lenders typically look at:

    • Credit Score

    • Income stability

    • Cash reserves or savings

    • Property value (current or projected post-ADU)

    Each loan type has its own requirements, SD3DU can connect you to trusted lenders.

  • Yes. Limits depend on:

    • Loan type

    • Your property’s value

    • Local lending regulations

    Some lenders consider future appraised value with the ADU completed, increasing your loan capacity.

  • SD3DU does not offer direct financing but can refer you to preferred lenders who specialize in ADU and residential construction loans.

  • Yes, but only for the new ADU, not your entire property.

    • Your main home stays protected under Prop 13

    • The ADU is assessed separately

    • On average, property taxes increase by ~1% of the ADU’s value

    Example: A $120,000 ADU = ~$1,200/year or $100/month in additional property taxes.

  • Yes, if you rent your ADU, you can:

    • Depreciate the structure over 27.5 years (residential property depreciation)

    • Accelerate depreciation using bonus depreciation or cost segregation studies

    Consult a tax professional to maximize deductions and reduce taxable income.

  • A cost segregation study is performed by a certified engineer to reclassify ADU components into shorter depreciation schedules:

    • 5-Year – Appliances, cabinetry, flooring

    • 7-Year – Fixtures, some electrical

    • 15-Year – Landscaping, paving, driveways

    This can significantly increase upfront tax deductions.

  • We don’t perform them directly, but SD3DU can refer you to qualified cost segregation specialists who offer physical inspections and IRS-compliant reports.

  • In San Diego, ADU rents generally range from $1,200 to $2,500+ per month, depending on:

    • ADU size and layout

    • Number of bedrooms/bathrooms

    • Amenities (laundry, parking, upgrades)

    • Location and demand
       

    Compare listings on Zillow, Craigslist, or Rentometer for local comps.

  • No. Short-term rentals are not allowed, leases must be 31 days or longer.

  • Cash flow = Rental income minus expenses (loan payments, maintenance, taxes, etc.)

    Example:

    • Monthly Rent: $2,000

    • Monthly Costs: $1,500

    • Cash Flow: $500/month
       

    Positive cash flow helps cover your mortgage and increases ROI.

    • Annual Rent: $24,000

    • Annual Expenses: $12,000

    • Net Profit: $12,000

    • Total ADU Cost: $200,000

    • ROI = (12,000 / 200,000) × 100 = 6%
       

    A higher ROI means a more profitable investment. Factors like financing, rent potential, and design efficiency all influence your return.

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