Core Construction · Sacramento ADU Specialist · Since 1991

Designing the Perfect ADU

Layouts, Budgets & Buildouts — everything Sacramento homeowners need to know before building.

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$1,500–$2,500

Monthly rental income
Sacramento market (2026)

20–30%

Property value increase
from a permitted ADU

95%

Average occupancy rate
ADU rentals in Sacramento

$118,440

Avg. equity added to a
$423K Sacramento home

35+

Years serving Sacramento
Est. 1991 · Lic. #993478

The Basics

What Is an ADU?

An Accessory Dwelling Unit is a fully independent living space — with its own kitchen, bath, and entrance — built on your existing residential lot. In Sacramento, they're now easier to build than at any point in history.

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Detached ADU

Stand-alone structure in your backyard. Most popular, most versatile. Maximum rental income potential.

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Attached ADU

Addition to your main home with its own entrance. Shares one wall. Cost-effective on smaller lots.

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Garage Conversion

Convert your existing garage into livable space. Often the most affordable option — no new footprint.

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The Goat 740™

Core Construction's signature 740 sq ft ADU. 1–2 bed, vaulted ceilings, 2 patios. From $169,000.

Key Sacramento Facts

✅No owner-occupancy requirement — you can rent BOTH your main home and your ADU

✅Ministerial permit approval — no neighbor input, no discretionary design review needed

✅Up to 2 detached ADUs + 1 Junior ADU allowed on most single-family lots under state law

✅HOA cannot block ADU construction — California state law overrides HOA rules

✅Impact fees waived for ADUs under 750 sq ft in Sacramento County

Choosing the Right Fit

Layout Options

The right ADU layout depends on your lot size, setbacks, goals, and budget. Here's how the main options compare.

Type	Size	Est. Cost	Best For	Timeline
Detached ADU	400–1,200 sf	$150K–$350K+	Max income · privacy · independence	10–16 months
Attached ADU	300–800 sf	$100K–$220K	Smaller lots · shared utility savings	8–12 months
Garage Conversion	300–600 sf	$60K–$140K	Lowest cost · fastest · existing footprint	4–8 months
Junior ADU	Up to 500 sf	$40K–$90K	Interior conversion · lowest entry cost	3–6 months
The Goat 740™	740 sf	From $169,000	1–2 bed · vaulted ceilings · 2 patios	~10 months

💡 Core Tip: Every lot is different — setbacks, utility locations, and soil conditions vary by property. A free feasibility assessment tells you exactly what's possible on YOUR lot before you spend a dollar.

Where the Money Goes

Budget Breakdown

A realistic look at ADU costs in Sacramento — category by category.

Cost by Category

25–35%

Construction & Labor

Framing, roofing, insulation, finishes

15–20%

Foundation & Site Work

Excavation, concrete, grading

12–18%

Mechanical (MEP)

Plumbing, electrical, HVAC

10–15%

Cabinetry & Fixtures

Kitchens, baths, custom built-ins

8–12%

Design & Architecture

Plans, engineering, structural

5–10%

Permits & Fees

City/county fees, inspections

5–8%

Utility Connections

Water, sewer, electrical panel

5–10%

Contingency — NEVER SKIP

Buffer for unexpected conditions

Sample Budgets

Entry Level

Garage conversion or Junior ADU

$50K – $120K

Lowest risk · fastest ROI · limited size

Mid-Range

Attached or small detached ADU

$120K – $220K

Best balance of cost vs. rental income

Premium

Full custom detached ADU

$220K – $400K+

Max income · max value · long lifespan

⚠️ Always budget 8–10% contingency. Utility upgrades alone can add $8,000–$20,000.

Step by Step

The Build Process

What to expect from first conversation to move-in day — no surprises, no mystery.

Free Consultation & Feasibility

Week 1

Lot assessment, zoning check, setback review. Zero cost, zero commitment.

Design & Architectural Plans

Weeks 2–6

In-house design team creates permit-ready plans tailored to your lot.

Permit Submission

Weeks 6–8

We prepare and submit the full permit package to your city or county.

Permit Approval

4–16 weeks

Sacramento typical: 8–14 weeks. Impact fees waived for ADUs under 750 sf.

Site Prep & Foundation

Weeks 1–3 of build

Grading, excavation, concrete pour — the most critical phase for quality.

Framing & Rough MEP

Weeks 3–7

Structure goes up. Plumbing, electrical, and HVAC rough-in happens here.

Inspections

Multiple stages

City inspectors sign off at each phase — foundation, framing, MEP, final.

Finishes & Cabinetry

Weeks 7–12

Custom Core cabinetry, tile, flooring, fixtures, and paint go in.

Final Inspection & Certificate

Week 12–16

Certificate of Occupancy — your ADU is now legally rentable.

Keys & Move-In

First day of income

Total: 10–16 months for detached ADU. Garage conversions: 4–6 months.

The Financial Case

Your Return on Investment

Real Sacramento numbers — what your ADU investment returns over time.

The Goat 740™ — Real Example

Investment	From $169,000
Size	740 sq ft · 1–2 Bed · 1 Bath
Est. Monthly Rent	$1,800–$2,200
Annual Income	$21,600–$26,400
Payback Period	7–9 years
Equity Added	~$118,000+
10-Year ROI	~140–180%

$18,000–$30,000 per year in passive income. Your ADU can pay itself off in under 10 years.

Why Homeowners Build ADUs

67%

Rental Income

Offset mortgage · build passive wealth

18%

Family / Multi-gen

Aging parents · adult children · privacy

Home Office / Studio

Dedicated workspace · no commute

Property Value

Invest in equity · plan for future sale

Before You Sign Anything

Top Mistakes Homeowners Make

Learn from others — these are the most common and costly ADU errors in Sacramento.

❌ Skipping the feasibility study

Every lot is different. Setbacks, utility locations, and soil conditions vary. Homeowners who skip this step often discover costly surprises mid-project.

❌ Choosing a contractor based on price alone

The lowest bid is rarely the best value. Unlicensed contractors leave you with unpermitted work, failed inspections, and a structure that undermines your home's value.

❌ Underestimating the budget — especially utilities

Utility connections are the most overlooked cost. Electrical panel upgrades alone can add $8,000–$20,000 and weeks to your timeline.

❌ Not planning for the right tenant or use

Long-term rental? Family housing? Home office? Each changes the layout you need. Know your goal before you finalize the design.

❌ Ignoring access, privacy and natural light

Poorly sited ADUs are harder to rent at full market rate. Access, privacy from the main home, and natural light significantly affect rental value.

❌ Using fragmented design, permit and build teams

Separate architect + permit expediter + contractor creates accountability gaps. An integrated design/build firm owns every outcome.

Due Diligence

Questions to Ask Your Contractor

Don't hire anyone who can't answer all of these clearly and confidently.

❓ Are you licensed, bonded and insured in California?

→ Verify at CSLB.ca.gov — takes 30 seconds and protects everything.

❓ Have you built ADUs in Sacramento County specifically?

→ Local permit experience cuts weeks off your timeline.

❓ Do you handle design, permits AND construction in-house?

→ One team = one point of accountability. No finger-pointing.

❓ Can you provide 3 completed ADU references I can call?

→ Call them — ask if it was on time, on budget, and what went wrong.

❓ What is included in the contract — and what is NOT?

→ Appliances, landscaping, and utility hookups are commonly excluded.

❓ What is your change-order process if costs increase?

→ Every project has unknowns. A professional has a clear, fair process.

❓ Who is my direct point of contact throughout the project?

→ Insist on direct access to the owner or a dedicated project manager.

❓ What is a realistic timeline — and what could extend it?

→ If someone says 6 months for a full detached ADU, be skeptical.

Ready to Build Your ADU?

Start with a free, no-pressure consultation and lot assessment. We'll tell you exactly what's possible on your property — and what it will cost.

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Call Us

916.719.9979

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darko@corebg.com

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Website

corebg.com/adu

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Starting At

$169,000

Call Now — Free Consultation

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