Straight answers about ADUs & additions.
43 owner-first guides written by Eli Cohen for a Woodland Hills design-build company. No hype, no "quick tricks" — just what actually matters when you plan, permit, and build a project in Southern California.
Newest first.
Home Addition Permits in Ventura County (2026)
City or County RMA, Zoning Clearance and coastal permits on unincorporated land, Thousand Oaks oak rules, fire hazard zones, and the plan check steps in order.
Sunroom Addition Cost in Los Angeles & Ventura
Starting-at planning ranges for a permitted sunroom, the Title 24 glass limits for additions, sunroom vs. patio enclosure, and what moves the budget.
Master Suite Addition Cost in Los Angeles
Preliminary planning ranges for a master suite addition in LA, from a 300 sq ft suite to a 450+ sq ft luxury suite, and what moves the budget.
How ADUs actually work.
What Is an ADU? Types, Rules & Uses Explained
A plain-language explanation of accessory dwelling units — what legally counts as one, the five types, what a JADU is, and how homeowners actually use them.
ADU Floor Plans & Layouts: What Works at Each Size
How ADU layouts change from a studio to a two-bedroom — circulation, kitchen placement, storage, daylight, and the plan decisions that cost money later.
Creative ADU Ideas for Small Spaces and Tight Lots
Layout, storage, daylight, and siting ideas that make a 350–600 sq ft ADU live larger — plus the setback and utility realities that shape a small-lot design.
Can I Build an ADU in My Backyard in Los Angeles? A 2026 Feasibility Checklist
A practical checklist for Los Angeles backyard ADUs: jurisdiction, lot configuration, setbacks, overlays, utilities, access, and which ADU type fits your property.
ADU Utilities Explained: Sewer, Water, Electrical & Gas Planning in Los Angeles
Sewer laterals, water service, electrical capacity, gas versus all-electric, and metering — what has to be investigated on your parcel before design gets locked.
California ADU Guide for 2026: Planning, Permits, Costs & Construction
How detached, attached, conversion ADUs, and JADUs work in California — feasibility, permits, Title 24, utilities, budgets, and the questions to ask a contractor.
Budget ranges and what moves them.
Sunroom Addition Cost in Los Angeles & Ventura
Starting-at planning ranges for a permitted sunroom, the Title 24 glass limits for additions, sunroom vs. patio enclosure, and what moves the budget.
Master Suite Addition Cost in Los Angeles
Preliminary planning ranges for a master suite addition in LA, from a 300 sq ft suite to a 450+ sq ft luxury suite, and what moves the budget.
Kitchen Addition & Bump-Out Cost in California
What it takes to grow a kitchen's footprint: bump-out vs. full addition, foundation, roof tie-in, utilities, permits and planning ranges.
Above-Garage ADU Cost in Los Angeles: What Drives the Budget
Preliminary planning ranges for an ADU over a garage in LA, and the structural, stair, fire-separation and utility items that move the number.
How to Finance an ADU in California
Cash, HELOCs, home equity loans, cash-out refinancing, renovation and construction loans, and grants: how each works for an ADU build.
Garage Conversion Cost in Los Angeles: What Drives the Budget
What actually moves the cost of converting a garage into an ADU or living space in LA — slab, utilities, egress, energy code, parking, and finishes.
ADU Rental Income in California: What to Plan For
How to research realistic ADU rent, the costs that come out of it, short- vs. long-term rules, and how lenders and taxes treat the income.
How Much Does It Cost to Build an ADU in California?
What an ADU actually costs to build in California — hard costs, soft costs, utilities, and the site conditions that move the number most.
Home Addition Cost: What Actually Shapes the Number
A plain-language breakdown of home addition cost — square footage, structure, utilities, finishes, professional fees, and contingency.
Second-Story Addition Cost in California (2026)
Why building up costs more per square foot than building out, what the structural work involves, and how to budget a second-story addition.
Cost of Adding a Bedroom to a House in California
What drives the cost of adding a bedroom, how a bedroom-plus-bath compares, and the code requirements a room must meet to count as a bedroom.
How to Pay for a Home Addition or ADU
The common ways California homeowners fund an addition or ADU — equity, renovation loans, construction loans, cash — and the trade-offs of each.
Room Addition Cost in Los Angeles: 2026 Planning Guide
Preliminary planning ranges for a Los Angeles room addition, what drives cost up or down, and how a written proposal replaces any guess.
ADU Cost in Ventura County: 2026 Planning Ranges
Preliminary planning ranges by ADU type for Ventura County, plus the hillside, fire-zone, oak-tree, and septic factors that move a local budget.
How Much Does an ADU Cost in Los Angeles & Ventura Counties?
Preliminary planning ranges by ADU type, the seven factors that move a budget, hard vs. soft costs, and how to compare two proposals fairly.
How Much Does a 500 Sq. Ft. ADU Cost in Los Angeles? 2026 Planning Guide
What actually moves the budget on a 500-square-foot Los Angeles ADU: type, site conditions, utilities, finishes, soft costs, and how to compare two proposals.
Permits, setbacks, and schedules.
Home Addition Permits in Ventura County (2026)
City or County RMA, Zoning Clearance and coastal permits on unincorporated land, Thousand Oaks oak rules, fire hazard zones, and the plan check steps in order.
Two-Story ADUs in Los Angeles: What the Rules Allow
How state height minimums, local zoning and overlay zones decide whether a two-story ADU fits your LA-area lot, plus design and cost drivers.
ADU Impact Fees in California: What You Pay and What Is Exempt
The 750 sq ft impact fee rule, school fees, utility connection charges and the permit fees that still apply in Los Angeles and Ventura counties.
How Big Can an ADU Be in California? Size & Height Rules
What state law says about maximum ADU square footage, the 800 sq ft protection, height allowances, and JADU limits — and why your city still matters.
How Long Does a Home Addition Take?
A realistic calendar for a California home addition — design, engineering, plan check, construction, inspections — and what stretches each stage.
Do I Need a Permit for a Kitchen Remodel in California?
When a kitchen refresh needs no permit, when a permit is required, and the inspections that apply when walls, plumbing, or electrical move.
ADU Permits in Ventura County: City vs. County
City departments vs. Ventura County RMA, oak and fire-hazard review, hillside and septic conditions, and the ADU approval sequence step by step.
Home Addition Permits in Los Angeles: A 2026 Homeowner's Guide
How addition permits work in the City of Los Angeles — zoning checks, regular vs. counter plan check, HPOZ review, 2025 Energy Code compliance, and inspections.
ADU Permit Timeline in Los Angeles: What Homeowners Should Expect in 2026
The phases every Los Angeles ADU moves through — feasibility, design, submittal, plan check, issuance, inspections — and what actually stretches the schedule.
How Long Does It Take to Build an ADU in Los Angeles? Design to Final Inspection
The full project calendar for a Los Angeles ADU — feasibility, design, permitting, construction, inspections, closeout — and what compresses or stretches each stage.
ADU Setback Requirements in California: A Homeowner's 2026 Guide
How ADU setbacks work in California, why the answer is parcel-specific, and how to read your own lot using the March 2026 HCD ADU Handbook as the reference.
Turning existing space into living space.
Can I Convert My Garage Into an ADU in California?
The feasibility checklist for a garage-to-ADU conversion — structure, setbacks, utilities, parking, and the city-specific rules that decide it.
Garage Conversion to ADU: A California Homeowner's Guide
Feasibility on an existing garage, the habitability upgrades code requires, parking rules under state law, permit paths, and the mistakes that stall plan check.
Comparisons that settle the question.
Junior ADU vs. ADU: Which One Fits Your California Home?
How a JADU differs from a standard ADU — size, kitchen, bathroom, owner-occupancy, permits, and budget drivers — and how to pick the right one for your lot.
How Much Value Does an ADU Add to Your Home?
How appraisers and buyers treat an ADU, why permitted square footage matters, and the honest limits of any value estimate before an appraisal.
Can I Add a Bedroom to My House? Permits, Cost & Feasibility in California
What makes a bedroom addition feasible, when you need a permit, how it differs from an ADU, and the budget factors that shape the project.
ADU vs. Second-Story Addition: Which Adds More Value?
Compare a backyard ADU with building up — cost, zoning, disruption, rental income, and which option fits your lot and long-term plans.
Home Addition vs. Moving: Which Makes More Financial Sense?
How to compare the true cost of adding on with the cost of selling, buying, and moving — including the less obvious numbers.
ADU vs. Room Addition: Which Is Right for Your Home?
A side-by-side comparison of cost, permits, rental potential, yard impact, and livability — plus how your lot should influence the decision.
Attached vs. Detached ADU: Cost, Privacy, Design & Property Considerations
Sharing a wall with the main house versus standing alone: how each option changes construction cost, privacy, utilities, yard use, and long-term flexibility.
Detached ADU vs. Garage Conversion in Los Angeles: Which Is Better for Your Property?
How a new detached unit and a converted garage differ on budget, yard space, design freedom, unknowns, rental appeal, and schedule — and how your lot decides it.
Practical tools for planning your project.
Cost estimator
Interactive ADU and addition budget calculator with region, finish, and site adjustments.
The 7-step process
How HomeAdd runs feasibility, design, permits, and construction on every project.
Free feasibility check
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Free feasibility & zoning check for your address across Greater Los Angeles.