Garage conversion guide
40 garage conversion questions San Diego homeowners actually ask.
Real questions homeowners search before converting a garage into an ADU, gym, office, or extra bedroom — answered with contractor-grade detail on permits, costs, structural work, and the mistakes that cost the most.
These are the exact questions San Diego homeowners ask before converting a garage — covering ADU rules under California SB 9 and AB 68, budgets, permits through San Diego DSD, structural work, insulation and HVAC, and the mistakes that turn a smart conversion into a regret. Written by a CSLB-licensed San Diego general contractor.
Section 1 of 8
Budgeting & costs
How much it actually costs to convert a garage in San Diego — and where the money goes.
How much does a garage conversion cost in San Diego in 2025–2026?
Garage conversions in San Diego fall into three tiers depending on scope. A basic non-permitted finish — drywall, flooring, paint, basic lighting — without plumbing or a kitchen runs $15,000–$30,000. A mid-range permitted conversion to a bedroom, office, gym, or studio with insulation, HVAC, and electrical upgrades runs $35,000–$75,000. A full ADU (accessory dwelling unit) conversion with kitchen, bathroom, separate entry, and code-compliant living space runs $80,000–$180,000+. The single biggest variable is whether you're adding a kitchen and bathroom (turning it into a true ADU). Always budget a 15–20% contingency — older San Diego garages frequently reveal foundation cracks, termite damage, and outdated electrical that must be addressed before finish work begins.
Is a garage conversion cheaper than building an addition?
Yes, significantly. A garage conversion to ADU runs roughly $80,000–$180,000 in San Diego; a comparable detached new-construction ADU runs $200,000–$400,000+. You're reusing existing walls, roof, and foundation. The savings come from skipping foundation work, framing, exterior siding, and roofing. The trade-offs: you lose covered parking, ceiling height is often limited (most garages are 8 ft vs the 9–10 ft you'd build), and existing structural quirks (sloped slabs, low headers, undersized footings) sometimes force expensive corrections. For most homeowners, garage conversion is the highest-ROI way to add a permitted dwelling unit.
What is the most expensive part of a garage conversion?
If you're adding a kitchen and bathroom, plumbing is the single biggest cost driver — running supply lines, drains, and venting through a slab that wasn't built for them often runs $8,000–$20,000. If you're skipping plumbing, the most expensive items shift to structural work (replacing the garage door with a code-compliant exterior wall), HVAC, and insulation. Typical full ADU breakdown: plumbing 15–20%, electrical 10–15%, HVAC 8–12%, insulation and drywall 10–15%, kitchen 10–15%, bathroom 8–12%, finishes (flooring, paint, trim) 10–15%, permits and plans 3–6%, labor distributed across all trades.
Will a garage conversion add value to my home?
Yes — but only if it's permitted. A permitted ADU adds substantial value: in San Diego County, a 400–700 sq ft attached ADU typically adds $80,000–$200,000+ to home value depending on neighborhood and finish level. The ROI on a permitted ADU is often 70–110% of the build cost. An unpermitted conversion, by contrast, can REDUCE home value — buyers and lenders treat it as a liability since it doesn't appear in legal square footage, may require removal at sale, and creates insurance complications. Always pull permits. Non-ADU conversions (gym, office, bedroom) add less value than an ADU but still recoup 50–70% if permitted and properly executed.
How do I set a realistic budget for a garage conversion?
Start with the question: am I adding a kitchen and bathroom or not? That single decision swings cost by $40,000–$80,000. Then: get 3 itemized contractor quotes — line by line, not a single number. Add a 15–20% contingency for structural surprises (San Diego garages often have undersized footings or termite damage). Confirm with San Diego DSD what your specific lot qualifies for — by-right ADU, junior ADU, or only a non-living conversion. List must-haves vs nice-to-haves in writing before the first contractor visit. Ask explicitly what's NOT included — many quotes exclude utility upgrades (often $5,000–$15,000), permit fees, design fees, and impact fees, all of which can add up fast.
Section 2 of 8
California ADU rules
What state and San Diego law actually allow on your lot.
Can I legally convert my garage into an ADU in California?
In nearly every case, yes. Under California state law (AB 68, AB 671, SB 9, and follow-on legislation), every single-family lot in California is entitled to at least one ADU and one junior ADU "by right" — meaning the city cannot deny it as long as it meets state-mandated minimum standards. A garage conversion to ADU specifically benefits from streamlined rules: minimum lot setbacks of 4 feet are typical, parking replacement is NOT required, and minimum unit sizes are protected by state law. San Diego has adopted these standards and added bonus programs that allow even more ADUs on some lots. Always verify with San Diego DSD what your specific lot zoning allows — but the default answer is yes.
What is the difference between an ADU and a junior ADU?
An ADU (accessory dwelling unit) is an independent dwelling — kitchen, bathroom, sleeping area, and its own entrance — up to about 1,200 sq ft in most California jurisdictions. A junior ADU (JADU) is smaller — capped at 500 sq ft — and is created within the existing footprint of the primary home (which can include a converted attached garage). JADUs can share a bathroom with the main home and must have an efficiency kitchen. The key advantage of a JADU: streamlined permitting, lower impact fees, and often faster approval. Many garage conversions qualify as JADUs and benefit from the easier approval path. Some lots are eligible for both — one full ADU and one JADU.
Do I need to replace parking when I convert my garage?
No — and this is one of the most powerful pro-ADU rules in California law. Under state law, converting a garage to an ADU does NOT trigger a replacement parking requirement, regardless of local zoning. This was a major change from prior rules. The only exception: if your lot is in a special historic district with explicit overlays. For 99% of San Diego homeowners, you can convert your garage to an ADU and never replace the parking spot. This is why garage-to-ADU conversions have exploded since 2020.
What is the minimum size for a garage conversion ADU?
California state law mandates that ADUs at least 150 sq ft in size be allowed. Most jurisdictions, including San Diego, set the practical minimum higher because of the kitchen, bathroom, and sleeping area requirements — realistically, a livable ADU starts around 220–300 sq ft. A standard one-car garage (roughly 200–250 sq ft) can be converted to an ADU but is tight. A two-car garage (400–500 sq ft) is the sweet spot — large enough for a comfortable studio or one-bedroom with full bath and kitchen. For a junior ADU specifically, the maximum is 500 sq ft and the minimum is whatever the city allows (typically 150–200 sq ft).
Can I rent out my converted garage ADU?
Yes — and this is the primary financial appeal. California law allows ADUs to be rented as long-term housing (30+ day leases) on any single-family lot. As of 2025, short-term rentals (under 30 days, like Airbnb) of ADUs are restricted in many San Diego neighborhoods — verify your specific area's rules through San Diego DSD before assuming you can run an ADU as a short-term rental. Long-term rental income for a permitted San Diego ADU typically ranges from $1,800–$3,500/month depending on size, finish level, and neighborhood. That's $21K–$42K annual income on a $100K–$150K conversion — which is why permitted ADUs are one of the strongest real estate plays in California.
Section 3 of 8
Permits, plans & timelines
What permits you need, how to get them, and how long it really takes.
Do I need a permit to convert my garage?
Yes — any conversion that adds living space, plumbing, or electrical circuits requires permits through San Diego DSD (Development Services Department). Even a non-living "finished garage" used as a workshop or gym typically needs a permit if you're adding electrical circuits, insulation as living space, or replacing the garage door with a wall. The only conversions that might not require permits: paint, basic shelving, lightweight non-attached flooring. If you're spending more than $5,000 on the project, assume you need permits. An unpermitted conversion can void your homeowner's insurance, force expensive remediation at sale, and create code enforcement liability.
How long does it take to permit a garage conversion in San Diego?
Permit timelines for garage conversions in San Diego have improved dramatically since California's ADU streamlining laws. For a standard ADU conversion: 4–8 weeks for permit approval. For a junior ADU: often 3–6 weeks (streamlined). For a non-ADU conversion (gym, office, bedroom): 4–8 weeks. State law requires San Diego to approve compliant ADU permits within 60 days of a complete submission — and the city has been hitting this consistently. Construction itself takes 8–14 weeks for a typical ADU conversion. Total timeline from first contractor consultation to a finished, permitted ADU: 5–9 months.
How long does a garage conversion take to build?
Construction timelines for a fully permitted garage conversion in San Diego: ADU conversion (kitchen + bath + full living space) typically runs 10–14 weeks of active construction. Non-ADU conversion (bedroom, gym, office, no kitchen/bath) runs 6–10 weeks. JADU conversion (smaller, often sharing main house plumbing) runs 8–12 weeks. Material lead times for cabinets, windows, and bath fixtures can stretch timelines by 4–8 weeks if you start ordering too late. Order long-lead items immediately after plans are submitted — don't wait for approval.
What plans do I need to submit for a garage conversion?
San Diego DSD requires: a site plan showing the existing garage and surrounding structures with setback dimensions; floor plans showing existing layout and proposed new layout with all walls, doors, windows, fixtures, and dimensions; elevation drawings showing exterior changes (new windows, replaced garage door); a structural plan if you're modifying load-bearing walls, replacing the garage header, or changing the roof line; an electrical plan showing new circuits, panel upgrade if needed, and Title 24 compliance; a plumbing plan if adding kitchen or bath; mechanical/HVAC plan if conditioning the space; and Title 24 energy compliance forms. A licensed contractor or architect prepares these; expect $2,500–$8,000 in plan preparation cost depending on complexity.
How much do garage conversion permits cost in San Diego?
Permit and fee costs for a garage conversion in San Diego typically run $4,000–$12,000 total depending on whether it's an ADU and the project value. Breakdown: building permit fees are based on valuation (typically $1,500–$4,500 for ADU conversions); plan check fees ($800–$2,500); school impact fees apply to ADUs over 750 sq ft ($1,000–$3,000); and electrical, plumbing, and mechanical permits ($300–$800 each). California has waived many impact fees for ADUs under 750 sq ft — one of the biggest financial wins of recent ADU law. Get a written breakdown of all permit costs in your contractor's quote, not just a single line.
Section 4 of 8
Structural, foundation & insulation
The bones that turn a garage into a livable, code-compliant room.
Does my garage floor need work before conversion?
Almost always yes. Garage slabs in older San Diego homes have three common issues: (1) Slope toward the door — fine for cars, terrible for living space. The floor often needs leveling with self-leveling underlayment ($1,500–$4,000). (2) No vapor barrier or insulation — California Title 24 typically requires either insulating under the slab (impossible without removal) or insulating above with rigid foam plus a new subfloor. (3) Cracks and settling — repair before any finish work goes down. Some conversions raise the floor 4–6 inches by building a new wood subfloor over the slab to gain vapor barrier, insulation, and a level surface in one step — common solution that adds $4,000–$9,000.
What happens to the garage door during conversion?
The garage door is fully removed and the opening is framed in as a code-compliant exterior wall — typically with insulation, weather barrier, exterior siding to match the house, and either a window, a sliding glass door, French doors, or solid wall depending on the design. This single change costs $3,500–$10,000 depending on what you replace it with. For an ADU, a separate exterior door for the unit's entrance is required — often placed where the garage door used to be. Matching the new exterior to the existing house siding well is what separates "looks like a converted garage" from a clean, professional ADU.
How do I insulate a garage for conversion?
Garages are unconditioned spaces — converting one means bringing it up to Title 24 insulation standards. Walls: typically R-13 to R-21 batts (or spray foam) between studs after removing existing drywall or interior finish. If walls are exposed studs without sheathing, exterior sheathing and weather barrier may need to be added. Ceiling/roof: R-30 to R-38 batts or blown-in insulation in the attic or rafter bays. Floor: rigid foam (R-10 to R-15) on top of the slab, then plywood subfloor — or under-slab insulation if you're pouring new. Windows must be dual-pane Low-E. Total insulation package cost: $4,000–$12,000. The single biggest comfort difference in a converted garage comes from doing insulation correctly.
Will my garage walls be tall enough to convert?
Most garages have 8-foot ceilings — the legal minimum for habitable space in California is 7'6" with some exceptions. Most garage conversions work without ceiling modifications. Problems arise when: (1) The garage roof has open trusses or a low collar tie creating sloped ceilings — sometimes those need to be re-engineered, adding $5,000–$15,000. (2) HVAC ducting, beams, or plumbing further reduce headroom. (3) You want a tall, modern ceiling — vaulting an existing ceiling is possible but requires structural review and $8,000–$25,000 in framing/finishing. Have your contractor measure ceiling height in every corner before signing — sloped or low garages can derail a project.
Will my foundation handle a garage conversion?
Usually yes, but it must be inspected. Older San Diego garages — especially pre-1980 — sometimes have undersized footings, no rebar in the perimeter foundation, or settling cracks. State law requires the foundation to support the new use. A structural engineer or experienced GC inspects: footing depth and width, crack patterns, slab condition, and connections to the main house. If the foundation is undersized, options include underpinning ($8,000–$25,000+), adding a new perimeter footing ($5,000–$15,000), or in extreme cases, pouring a new slab. This inspection is usually $400–$900 and is non-negotiable for permitted work. Don't skip it.
Section 5 of 8
Plumbing, electrical & HVAC
The systems that make a garage actually livable.
How do I add plumbing to a garage that has none?
Plumbing is usually the single biggest cost in a garage-to-ADU conversion. Supply lines (hot and cold water) typically run from the main house in trenches under the slab or a crawlspace — about $3,000–$8,000 depending on distance. Drains require either trenching through the existing slab (saw-cut and patch — $4,000–$10,000) or routing through a raised subfloor (cheaper, around $2,000–$5,000, but raises floor height). Sewer connection ties into the existing house lateral. Hot water can be a small electric tankless ($1,500–$3,000 installed) or a shared connection to the main house. Total plumbing budget for a kitchen + bath ADU conversion in San Diego: $12,000–$28,000.
Will my electrical panel handle a garage conversion?
Most older San Diego homes have 100-amp or 125-amp service — often insufficient when you add a full ADU with kitchen, HVAC, and water heater. Many conversions require an upgrade to 200-amp service ($3,000–$7,000) and a new electrical sub-panel in the ADU ($1,500–$3,500). For a non-ADU conversion (gym or office), you may get by with adding circuits to the existing panel. Title 24 requires LED lighting throughout, smoke and CO detectors, GFCI and AFCI protection on most circuits, and EV-ready conduit in many new permits. Get an electrical load calculation done before assuming your current panel is enough — the cost of finding out mid-project is much higher.
What HVAC system works best for a converted garage?
For most converted garages and ADUs in San Diego, a ductless mini-split heat pump is the right answer. Why: no ductwork required (huge cost savings since you can't easily run ducts through an existing structure), efficient for small spaces, heats AND cools, simple installation. Cost: $4,000–$8,000 installed for a single-zone system covering a 200–500 sq ft conversion. Alternatives: extending the main house HVAC ducts (often impractical and inefficient); window AC units (not permitted for habitable ADU space); electric resistance heating (allowed but very expensive to operate). Mini-splits are the contractor default and the right choice in 95% of San Diego garage conversions.
Do I need separate utilities for a converted garage ADU?
Not required by law, but worth considering. Most San Diego garage-to-ADU conversions share utilities with the main house — one electric meter, one gas meter, one water meter. This is simpler and cheaper to build. Pros of shared utilities: $3,000–$8,000 cheaper to install, no separate utility deposits. Cons of shared utilities: harder to bill a tenant accurately, you absorb their consumption. Separate sub-meters are a popular middle ground — single utility account, but you can measure ADU usage and bill a tenant precisely ($800–$2,500 to install). Fully separate utility services (own meters) cost $8,000–$20,000+ and require coordination with SDG&E and the local water authority.
How do I add windows to a converted garage?
Most garages have one or two small windows (often single-pane and not code-compliant). Conversions typically add 2–4 new windows for natural light, ventilation, and emergency egress. California building code requires a bedroom to have an egress window — minimum 5.7 sq ft of openable area, 24" minimum height, 20" minimum width, sill no more than 44" off the floor. Window installation runs $800–$2,200 per window installed including framing and exterior siding patch. For an ADU, plan on 3–5 new windows totaling $3,000–$10,000. Don't skip natural light — it's the single biggest difference between a converted garage that feels like a real living space and one that feels like a finished garage.
Section 6 of 8
What to convert your garage into
ADU vs gym vs office vs bedroom — what each use case actually costs and returns.
Should I convert my garage into an ADU or a regular bedroom?
Decision driver: do you want rental income or expanded family space? ADU pros: rental income of $1,800–$3,500/month in San Diego, adds substantial home value (often $80K–$200K), increases marketability significantly. ADU cons: highest cost ($80K–$180K), more permit complexity, dedicated kitchen and bath take floor area. Regular bedroom pros: cheapest conversion ($35K–$60K), maximum living area for the budget, family-friendly. Regular bedroom cons: doesn't legally count as a bedroom in MLS unless it has egress and meets habitable requirements, less ROI at resale, no rental income. For homeowners with the budget AND a financial-return goal: ADU. For homeowners adding family space without rental ambitions: bedroom conversion.
What does it cost to convert a garage to a home gym?
A home gym conversion is one of the simpler garage projects. Scope: insulation, drywall, flooring, lighting, electrical for outlets and AC, basic HVAC. No plumbing, no kitchen. Typical cost in San Diego: $20,000–$45,000 depending on finish level and HVAC choice. Permits are still required since you're changing the use and adding electrical. Flooring is the gym-specific decision — rubber gym tile ($3–$7/sq ft) is the standard. Ceiling height matters — measure before buying tall equipment. Add ample electrical (220V circuit for an EV charger or future use is smart while walls are open). A converted gym typically recoups 30–50% at resale — lower ROI than ADU, but high lifestyle value.
How do I convert my garage into a home office or studio?
A home office or studio is the second simplest conversion. Scope: insulation, drywall, finished floors, lighting, ample outlets, HVAC, sometimes a small bathroom. Typical cost: $25,000–$60,000 depending on whether you add a bathroom. Key design considerations: lots of natural light (3–4 new windows minimum), good acoustic isolation if you're recording or on lots of video calls (consider double drywall and a solid-core door), dedicated electrical circuits for AV equipment, and Cat 6 ethernet pulled from the main house. A converted office adds 50–70% of cost to home value and is increasingly desirable to remote-work-era buyers.
Can I convert just part of my garage and keep parking?
Yes — partial conversions are common, especially for two-car garages. Convert one bay into a finished room while keeping the other as parking. The wall between them is fire-rated (typically 5/8" Type X drywall both sides). Permits are still required. Cost is usually proportional — converting half of a 400 sq ft two-car garage runs $25,000–$60,000. The trade-off: you can't make the converted half into an ADU because ADU rules require separate entry and full living facilities, which are tough to achieve in half a garage. Partial conversions are best for gym, office, or bonus room — not ADU.
Is converting an attached vs detached garage different?
Yes, in three important ways. Detached garage conversions are more flexible for ADU use — easier to give a private entry, less fire-rating complexity, the ADU feels more separate from the main house (better for rental). Attached garage conversions are cheaper for plumbing and electrical (shorter runs from the main house) but require fire-rated walls between the converted space and the main house (Type X drywall, self-closing doors). Acoustic separation is harder with attached. For a junior ADU (which by law must be within the existing home footprint), attached garage is required. For a regular ADU, detached is often the better path if you have one.
Section 7 of 8
Design, layout & finishes
How to make a converted garage feel like a real room, not a finished garage.
How do I make a converted garage not look like a converted garage?
The difference between a clean conversion and an obvious one usually comes down to five things: (1) Replace the garage door with a real wall that matches the house siding seamlessly — color, texture, trim, and reveal lines should match. (2) Add proper-sized windows (not tiny garage-style ones) — 3–4 large windows transform the space. (3) Raise the floor or level the slab so the room is flat and feels like the rest of the house. (4) Pay attention to ceiling height — don't leave exposed joists or open trusses unless intentional. (5) Match interior trim, baseboards, and door styles to the main house. These five details cost $8,000–$25,000 total and are the difference between adding $80K and $180K in value.
What is the best floor plan for a garage-to-ADU conversion?
For a two-car garage (400–500 sq ft), the most efficient ADU layout: kitchen along one wall (galley layout takes up only 4 feet of depth), bathroom in a back corner (5x7 minimum), with the remaining open area as a combined living/sleeping space. A Murphy bed or sleeping loft preserves living square footage during the day. Place the entry door where the garage door used to be — that's the natural front of the unit and gives it good street presence. Run plumbing along one shared wall (kitchen and bath back-to-back) to minimize cost. Don't divide the open area into too many small rooms — open layouts feel much larger in 400 sq ft than chopped-up floor plans.
What flooring works best in a converted garage?
Luxury vinyl plank (LVP) is the most popular and practical choice — $4–$9/sq ft installed, fully waterproof (important over a concrete slab), warm underfoot with proper underlayment, modern aesthetic. Engineered hardwood works if the slab is dry and properly prepared, but moisture from the slab is a real risk in older San Diego garages without vapor barriers. Polished or stained concrete is striking and durable (perfect for gyms or modern ADUs) — costs $4–$10/sq ft. Carpet works only in bedroom-only conversions. Avoid solid hardwood directly on slab — moisture issues will ruin it within a few years. Whatever flooring you choose, the slab prep (leveling, vapor barrier, moisture testing) matters more than the surface material.
How do I add a kitchen to a converted garage?
A garage-to-ADU kitchen typically runs $8,000–$25,000 depending on size and finish. Compact ADU kitchens use stock cabinets (24"–30" base depth), a 24" range or induction cooktop, a 24" undercounter refrigerator, and a single-bowl sink. For tight spaces, an "efficiency kitchen" (allowed for junior ADUs) uses a 2-burner cooktop, an under-counter fridge, and a sink — no full range required. Plumbing rough-in for the kitchen is usually combined with bathroom rough-in to share trenches. Save money by buying a stock cabinet line at Home Depot or IKEA, splurge on a quartz countertop ($1,500–$3,000) — it's the single visible upgrade that elevates the whole space.
How do I add a bathroom to a converted garage?
A 5x7 ADU bathroom (the minimum practical size) typically costs $9,000–$18,000 installed. Includes a 32"x60" shower (skip the tub to save space), a comfort-height toilet, a 24" or 30" vanity, exhaust fan, GFCI outlets, and porcelain tile floor. Plumbing is the biggest cost — supply lines and drains routed from the main house. Locate the bathroom in a corner adjacent to existing utilities to minimize cost. Keep the layout simple: shower in one corner, toilet next to it, vanity on the opposite wall. Tankless water heaters or shared water heating with the main house both work. Waterproof the shower properly — see the bathroom remodeling guide for the systems that matter.
Section 8 of 8
Common mistakes & problems
The expensive mistakes — and what to do when something goes sideways.
What are the biggest mistakes people make in a garage conversion?
The most expensive mistakes: (1) Skipping permits to "save time" — devastating at resale and for insurance. (2) Underestimating the floor — sloped or unsealed slabs cause moisture and leveling problems that cost $5,000–$10,000 to fix after finish work is in. (3) Hiring an unlicensed contractor for a project that requires plan-checked permits — work will fail inspection. (4) Forgetting Title 24 energy compliance — insulation, windows, lighting, and HVAC all have minimum standards. (5) Not getting an electrical load calculation early — discovering you need a $5,000 panel upgrade mid-project is a budget killer. (6) Cheap exterior — siding that doesn't match the house is the #1 visible giveaway of a poor conversion.
What hidden problems show up during garage conversions?
Once walls and floor open up, San Diego garages frequently reveal: termite and dry-rot damage in the studs and bottom plates (common in pre-1980 homes — $2,000–$8,000 to remediate). Inadequate or missing footings under the perimeter foundation (especially garages built as "carports" later enclosed). Old aluminum wiring or knob-and-tube circuits requiring full rewire ($5,000–$15,000). Asbestos in old drywall, vinyl tile, or pipe insulation — abatement runs $2,000–$10,000+. Moisture intrusion from sloped grade around the foundation. Sloped or cracked slab requiring leveling. Build a 15–20% contingency into the budget — these surprises are the rule, not the exception.
Can my unpermitted garage conversion be legalized after the fact?
Often yes, but it's painful and expensive. San Diego allows "permit by review" or retroactive permitting for many existing conversions — but the work must meet current code, which often means opening walls to verify insulation, electrical, and plumbing. Costs to legalize a previously unpermitted conversion typically run $10,000–$40,000 in remediation plus permit fees. The cost is often half to two-thirds of doing it right the first time. Always pull permits upfront. If you bought a home with an existing unpermitted conversion, a contractor can usually evaluate and quote retroactive permitting — and selling a property "as is" with unpermitted square footage is increasingly difficult as buyers and lenders scrutinize permit records.
How do I keep my garage conversion on budget?
The proven tactics: (1) Get a fixed-price, line-itemed contract — not time-and-materials. (2) Finalize every selection (windows, doors, flooring, cabinets, fixtures) before construction starts — change orders during construction are 15–25% more expensive than upfront decisions. (3) Build a 15–20% contingency into the budget and don't spend it on upgrades. (4) Value-engineer where it doesn't show — stock cabinets and porcelain tile vs custom and natural stone. (5) Don't move plumbing unless necessary — every foot of relocation adds $500–$1,500. (6) Get an electrical load calc and structural inspection BEFORE signing a contract so you know about panel upgrades and foundation work upfront.
What questions should I ask a garage conversion contractor before I hire them?
(1) What is your CSLB license number — and have you completed at least 5 ADU conversions in the last 12 months? (2) Can you send insurance certificates directly from your insurer? (3) Will you handle the structural inspection and electrical load calc before we sign? (4) Who is preparing the plans — you, an in-house architect, or a third party? (5) How do you handle Title 24 compliance and energy testing? (6) What does your payment schedule look like (legally limited to 10% deposit or $1,000)? (7) Who pulls permits and meets with inspectors? (8) Have you completed a permitted ADU conversion in my zip code in the last year? (9) Can I see 3 references for similar projects? (10) What's your current start lead time? A garage-to-ADU project is more complex than a typical remodel — vet experience aggressively.
What is the #1 thing to do before starting a garage conversion?
Get a written feasibility assessment from a licensed contractor before you make any other decision. The assessment should answer: what type of conversion does my lot qualify for under California and San Diego rules (ADU, JADU, non-ADU)? What's the structural condition of the foundation, slab, and existing framing? What's the electrical load calculation — will I need a panel upgrade? How will plumbing be routed if I'm adding a kitchen and bath? What's the realistic budget range, and how does that compare to my goals? This typically costs $0–$500 and is the foundation every other decision rests on. Without it, every choice — design, scope, finishes — is built on guesswork.
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