I’m Daniel Dechner, Lead Project Manager at IL Total Design & Build, and the question I hear most from homeowners before they commit to a project is some version of this: “How long is this actually going to take?”
It’s the right question — and it deserves a straight answer, not a vague “it depends.”
After managing ADU and home addition projects throughout San Diego, I’ve seen every version of how a construction schedule can go right and how it can go sideways. The difference almost always comes down to one thing: how well the pre-construction process was managed before a single shovel hit the ground.
A missed permit submission, a subcontractor who wasn’t coordinated, materials that arrive out of sequence — any one of these can turn a 6-month project into a 10-month one. This guide walks you through every phase of an ADU or home addition build in San Diego, with realistic timeframes and the specific things we do at IL Total Design to keep projects on track.
The Full Timeline at a Glance
Before we go phase by phase, here’s a realistic summary of what to expect for different project types in San Diego:
| Project Type | Design & Permits | Construction | |
|---|---|---|---|
| Garage Conversion / JADU | 14–18 weeks | 8–14 weeks | |
| Attached ADU (under 500 sq ft) | 14–18 weeks | 14–20 weeks | |
| Detached ADU (under 800 sq ft) | 14–18 weeks | 18–26 weeks | |
| Detached ADU (800–1,200 sq ft) | 14–18 weeks | 18-26 weeks | |
| Home Addition / Room Addition | 10–16 weeks | 16–28 weeks |
These are realistic ranges — not best-case scenarios. They account for normal city review times, standard inspection sequencing, and typical material lead times. Projects with unusual site conditions, hillside lots, or complex structural requirements will run longer.
Phase 1: Initial Consultation & Property Assessment
Typical duration: 1–2 weeks
Every project starts here. Before any design work begins, we visit the property, review your goals, and assess what’s actually feasible given your lot, zoning, existing utilities, and budget.
This phase is often underestimated by homeowners who want to jump straight to design — but skipping a thorough site assessment creates problems downstream. We’ve seen projects where homeowners had already paid for design work, only to discover the property had setback constraints or utility conflicts that significantly changed what was buildable.
What we cover during the property assessment:
- Lot dimensions, setbacks, and zoning classification
- Existing utility locations (gas, electrical, sewer, water)
- Soil and grading conditions
- Access for construction equipment and materials
- Feasibility of the project type you’re considering
At the end of this phase, you’ll have a clear picture of what’s possible and a realistic budget range before spending a dollar on design.
Phase 2: Design & Plan Development
Typical duration: 3–6 weeks
Once the project scope is confirmed and a proposal is signed, our in-house design team gets to work on the construction documents. This is where the project takes shape on paper before anything is built.
For an ADU or home addition in San Diego, the permit set typically includes:
- Site plan — property layout, ADU footprint, setbacks, driveways
- Floor plans — room layout, dimensions, window and door locations
- Elevation drawings — all four exterior sides of the new structure
- Foundation and framing plans — structural details per engineering
- Mechanical, electrical, and plumbing schematics — where required
- Title 24 energy compliance report — required for all new construction in California
The length of this phase depends on project complexity and how quickly homeowners finalize their design decisions. The most common source of delays here is change of scope — clients who decide to modify layouts or add features mid-design. We address this by locking in the scope before design begins and running a formal change-order process for anything that comes up after.
Before plans are submitted to the city, we hold an internal plan review. Our PM and field lead review the drawings together to catch coordination issues — things like a plumbing chase that conflicts with a structural beam, or a window location that doesn’t account for a neighboring structure. Catching these issues on paper is hours of work. Catching them in the field is weeks.
Phase 3: Permit Submittal & City Review
Typical duration: 4–10 weeks
This is the phase that surprises homeowners most — and the one that causes the most schedule anxiety. Permit timelines in San Diego vary based on project type, the current workload at the Development Services Department, and whether the city issues correction notices that require plan revisions.
Here’s how the permit process typically works for ADUs in San Diego:
Over-the-Counter (OTC) Review — Simpler projects like garage conversions and some JADUs may qualify for over-the-counter review, which can be approved in a single appointment or within a few days.
Standard Plan Check — More complex projects go through a standard plan check, which can take 4–8 weeks for a first review. If the city issues a correction notice (which is common — especially for structural or energy details), you’ll need to revise and resubmit, adding another 2–4 weeks.
Expedited Review — San Diego offers expedited plan check for an additional fee. This can cut review time significantly and is often worth the cost on larger projects where carrying costs are high.
What we do to minimize correction cycles:
- Submit complete, coordinated plan sets the first time — architectural, structural, Title 24, and soils report together
- Use digital submittal when available to avoid processing delays
- Monitor the plan check queue and follow up proactively with the city
- Respond to correction notices within 24–48 hours of receipt
The permit phase is largely outside of anyone’s direct control — but preparation going in directly affects how smoothly it goes.
Phase 4: Pre-Construction Setup
Typical duration: 1–2 weeks
Once permits are approved and in hand, there’s a critical window before construction starts that most homeowners don’t see — but that sets up everything that follows.
During pre-construction setup we:
- Schedule all subcontractors — framer, plumber, electrician, HVAC, stucco, drywall, and finish trades are all calendared against the project schedule
- Order long-lead materials — windows, exterior doors, and specialty items often have 3–6 week lead times. These get ordered at permit approval so they arrive on schedule for installation
- Arrange site logistics — porta-potty, dumpster, material staging area, and construction fencing are all set up before day one
- File SDGE applications — if the project requires electrical panel relocation or service upgrades, SDGE applications are submitted immediately. SDGE lead times can run 4–12 weeks, so this cannot wait
- Hold pre-construction meeting — homeowner, project manager, and lead subs review the schedule, access arrangements, daily work hours, and communication expectations
This phase is quiet from the homeowner’s perspective, but it’s where the difference between a smooth build and a chaotic one is made.
Phase 5: Site Prep & Demolition
Typical duration: 1–2 weeks
The first visible work on site — and often the most satisfying for homeowners who’ve been waiting through design and permits.
For new detached ADUs, this includes:
- Clearing and grubbing the construction area
- Removing existing structures (sheds, hardscape, fencing) as needed
- Grading and compacting the site
- Setting up erosion control if required by the city
- Marking utility locations before any excavation
For attached ADUs and home additions, demolition of existing walls, rooflines, or garage structures happens here — carefully sequenced so the main home remains secure and weathertight throughout.
Phase 6: Foundation
Typical duration: 2–4 weeks
Foundation work is slower than it looks — mostly because concrete cure time is non-negotiable. You can’t rush it.
The typical sequence:
- Excavation for footings and trenching for underground utilities
- Underground plumbing rough-in (sewer, water) — inspected before backfill
- Forming and setting anchor bolts and hardware per structural plans
- Concrete pour — foundation typically requires 7+ days of cure time before framing begins
- Foundation inspection by City of San Diego
If your project requires special inspection (which is common for ADU connections to the main home involving epoxy and all-thread anchors), a third-party special inspector must be present during those specific operations. We schedule this in advance — last-minute special inspection requests add unnecessary delay.
Phase 7: Framing
Typical duration: 2–5 weeks depending on size
Framing is the phase where the project becomes real. Walls go up, rooflines take shape, and homeowners can walk through the space for the first time and actually feel the scale of what’s being built.
The framing sequence:
- Pressure-treated sill plates installed on foundation
- Wall framing — exterior and interior walls, with openings for windows and doors
- Beam and header installation at larger openings
- Roof framing — joists, rafters, or engineered trusses per structural plans
- Roof sheathing and felt underlayment (to weatherproof the structure quickly)
- Window and door installation with proper flashing and waterproofing
- Shear wall installation per structural plans
- Shear wall and roof sheathing nailing inspection by City of San Diego
We hold our pre-rough-in coordination meeting during framing — before any walls are closed. This is where the plumber, electrician, and HVAC sub all walk the framed structure together and mark their rough-in paths. Catching conflicts before walls are closed saves significant time.
Phase 8: Rough Mechanical, Electrical & Plumbing
Typical duration: 3–5 weeks
With framing complete and the structure inspected, all three trades work through their rough-in simultaneously. Good scheduling coordination here keeps them out of each other’s way and maximizes efficiency.
Rough plumbing — supply lines (PEX), drain and vent lines (ABS), shower valve rough-in, exterior hose bibs. Underground plumbing was already done at foundation; this phase handles everything in the walls and ceiling.
Rough electrical — panel and subpanel work, all branch circuit wiring, dedicated circuits for appliances, recessed light wiring, exterior outlet and light locations. In San Diego, all new construction must meet current NEC code including arc-fault and GFCI requirements.
HVAC rough-in — ductwork or mini-split lineset runs, ventilation ductwork for bath and kitchen exhaust, attic or crawl space insulation prep.
All three trades must pass their rough inspections by the City of San Diego before insulation can begin. We schedule all three inspections as close together as possible to compress the timeline.
Phase 9: Insulation & Weatherproofing
Typical duration: 1–2 weeks
Once rough inspections are passed, insulation goes in and the exterior gets its weatherproofing layers.
Interior:
- Batt insulation in exterior walls (R-15 minimum) and ceiling/roof (R-30+) per Title 24
- Insulation inspection by City of San Diego
Exterior:
- Vapor barrier and wire lath on all exterior stucco surfaces
- Weep screed at plate lines
- Caulking of all exterior penetrations
- Lath inspection by City of San Diego
These two inspections — insulation and lath — are among the most commonly sequenced back-to-back in San Diego ADU projects. We don’t schedule one without having the other booked.
Phase 10: Drywall, Stucco & Exterior Finishes
Typical duration: 4–7 weeks
This is a longer phase because several of these steps have mandatory wait times built into them.
Stucco (exterior):
- Scratch coat — must cure 24–48 hours minimum
- Brown coat — must cure a minimum of 3 weeks before finish coat
- Color and texture coat — matched to existing home as closely as possible
This 3-week stucco cure time is the most common source of schedule surprises for homeowners who expect the exterior to be done faster. It’s not negotiable — applying finish coat too early leads to cracking.
Drywall (interior):
- Hang, tape, and mud all walls and ceilings
- Drywall screw inspection by City of San Diego
- Skip trowel or smooth texture applied
- PVA primer coat
Phase 11: Paint, Flooring & Interior Finishes
Typical duration: 3–5 weeks
The project starts looking like a real living space during this phase.
- Paint — two coats on walls and ceilings, up to three colors selected by homeowner. Doors, casings, and baseboards painted separately
- Flooring — LVP or laminate installation, self-leveling compound for low spots, transition moldings, and baseboard installation
- Interior doors — pre-hung doors set and casing installed
- Kitchen cabinets — sourced and installed (we assist with sourcing through our contractor network)
- Countertops — quartz templated and fabricated after cabinets are installed. Typical fabrication lead time is 10–14 days after template
- Tile work — bathroom shower walls, floor tile, kitchen backsplash
Phase 12: Finish Mechanical, Electrical & Plumbing
Typical duration: 1–2 weeks
With finishes in place, all three trades return to complete their work:
- Finish plumbing — sink, toilet, shower valve trims, faucets, garbage disposal, water heater, hose bibs
- Finish electrical — recessed light trims, outlets, switches, dimmers, cover plates, ceiling fans, exterior lights, smoke detectors, panel breakers
- HVAC — mini-split heads mounted and connected to condensers, exhaust fan covers installed
Phase 13: Final Inspection & Project Close-out
Typical duration: 1–2 weeks
The final city inspection is the last official step before you can occupy the ADU. An inspector reviews the completed work against the approved plans and checks all systems — structural, electrical, plumbing, mechanical, and life safety (smoke detectors, egress windows, etc.).
We prepare for final inspection by:
- Walking the project ourselves first and creating a punch list of any incomplete or incorrect items
- Confirming all finish items are installed and functional
- Verifying all required paperwork is in order (energy compliance documentation, special inspection reports, etc.)
Once final inspection is passed, the city issues a Certificate of Occupancy. The ADU is now legal, permitted, and ready to occupy or rent.
Project close-out includes:
- Final walk-through with the homeowner
- Punch list completion
- Final payment processed
- All permits, warranties, and product documentation handed over to the homeowner
What Causes Delays — And How We Prevent Them
In my experience, the most common sources of ADU construction delays in San Diego are:
1. Incomplete permit submittals — Missing a soils report, structural calculations, or Title 24 report triggers a correction notice and adds 2–4 weeks minimum. We submit complete, coordinated packages the first time.
2. SDGE delays — Panel relocations and temporary service setups can take 6–12 weeks through SDGE. We file immediately upon proposal acceptance — not at permit approval.
3. Homeowner decisions made late — Flooring, countertop, and fixture selections that aren’t finalized before construction begins cause cascading delays at finish stages. We give homeowners a selection deadline tied to the project schedule.
4. Material lead times — Windows, exterior doors, and specialty items often have 3–6 week lead times. We order these at permit approval, not when installation is scheduled.
5. Uninspected work — Proceeding with the next phase before a required inspection passes creates stop-work risk. We track every inspection in our project management system and never skip the queue.
Frequently Asked Questions
How long does it take to get an ADU permit in San Diego?
Standard plan check for a new detached ADU typically takes 4–8 weeks for a first review. If the city issues a correction notice requiring plan revisions, add another 2–4 weeks for resubmittal. Simpler projects like garage conversions may qualify for over-the-counter review, which can be approved in days. San Diego also offers expedited review for an additional fee.
How long does it take to build a detached ADU in San Diego from start to finish?
For a typical 600–800 sq ft detached ADU, expect 6–9 months total from signed contract to Certificate of Occupancy. This includes design, permitting, and construction. Smaller ADUs and garage conversions can be completed in 3–5 months. Larger or more complex projects can run 10–12 months.
What’s the longest part of the ADU construction process?
For most projects, the permitting phase takes the most calendar time relative to actual work being done — because you’re waiting on the city, not the contractor. During construction, the stucco phase has a mandatory 3-week cure time that homeowners are often surprised by.
Can construction start before permits are approved?
No — not for permitted work. Any construction that begins before permits are issued is unpermitted work, which creates significant legal and financial risk. Permit-ready plans can often be developed while financing is being finalized, but construction cannot start until the permit card is posted on site.
Does IL Total Design handle the permit process?
Yes. We manage the full permit submittal, all city correspondence, and coordination of every required inspection from foundation through final. Homeowners don’t need to manage any part of the permitting process.
What happens if the city issues a correction notice?
Correction notices are common — especially on first submittals. When we receive one, we respond within 24–48 hours with revised plans and resubmit. The goal is always to resolve corrections in a single round rather than going back and forth multiple times.
How does the payment schedule work relative to the construction timeline?
At IL Total Design, payments are tied to construction milestones — not arbitrary dates. You pay when verifiable progress has been made: foundation poured, framing complete, inspections passed. This protects you as a homeowner and gives us a clear incentive to keep the project moving.
What should I do to prepare my property before construction starts?
Clear the construction area of all personal belongings, furniture, and landscaping items. Ensure there’s reasonable vehicle access for a dump truck and material deliveries. If there are pets, arrange for them to be kept away from the work area during construction hours. We’ll walk through site-specific preparation requirements with you before job start.
Ready to See What Your Timeline Looks Like?
Every project is different. The best way to get a realistic schedule for your specific property and project type is to start with a conversation.
At IL Total Design & Build, we provide a detailed written proposal — including a projected timeline tied to each phase — before you commit to anything. There’s no cost and no obligation.
Schedule Your Free Consultation →
IL Total Design & Build | CA License #1058676 | San Diego, CA | (619) 404-0125 | Contact@ILTotalDesign.com
