An ADU construction checklist should connect every stage to a document, a responsible person, and a clear acceptance point. Before work starts, confirm the jurisdiction, approved plan set, written scope, exclusions, selections, utility assumptions, inspection path, and change-order method. During construction, review work before it is concealed, keep the current documents together, and record decisions in writing. At closeout, verify systems, complete the punch list, collect approvals and warranties, and understand who handles follow-up.
This guide is an owner-facing control sheet, not a substitute for the approved plans, the building official, an engineer, or the construction contract. Requirements and inspection sequences can vary by property and jurisdiction.
What should be confirmed before ADU construction starts?
The first useful question is not "When can the crew start?" It is "Which facts are confirmed, and where are they recorded?" A design can look complete while site access, utility routing, demolition limits, or owner selections remain assumptions. Those assumptions tend to reappear later as schedule changes, substitutions, or additional work.
Start with the reviewing jurisdiction and the exact approved plan set. California provides a statewide ADU framework, but the local agency still administers plan review, building permits, and inspections. The California HCD ADU Handbook is a reliable statewide reference. The permit record and the current local correction or approval documents control the property-specific path.
Next, connect the plans to the site. Confirm access, protection, staging, utility assumptions, drainage, and work that touches the existing home. Label unverified conditions as open instead of quietly treating every unknown as included.
| Confirm before start | Evidence to review | Owner checkpoint |
|---|---|---|
| Reviewing jurisdiction | Permit portal, issued permit, and current correction or approval record | Know which agency answers project-specific questions. |
| Approved design | Stamped or issued plan set with revision date | Keep one current set and remove superseded copies from circulation. |
| Existing conditions | Field measurements, site photos, surveys, reports, and utility information | Mark what was verified and what remains an assumption. |
| Construction access | Site logistics plan or written access description | Confirm gates, protection, delivery route, staging, and daily cleanup. |
| Owner decisions | Selection log with due dates and approved products | Prioritize items that affect framing, rough-ins, openings, or ordering. |
| Communication | Named contacts and update rhythm | Know who records decisions and who can authorize a change. |
For a broader feasibility and planning sequence, use the ADU guide and the Orange County ADU permit guide. For the team structure that connects design, approvals, and construction, see the ADU design-build process.
Which documents should control the work?
A good project does not rely on one giant document. It uses a small set of records that answer different questions. The issued plans show what is approved. The contract and scope show what the builder agreed to provide. Specifications and selection records identify products and finish decisions. Written changes explain later adjustments. Inspection records show agency checkpoints. Daily or weekly updates explain current progress without rewriting the contract.
These documents must agree. Resolve conflicts before ordering or installation. If a proposal says "site work included," the scope should state whether that covers excavation, export, trenching, utility connections, hardscape removal, restoration, or only part of that work.
| Document | What it controls | How to keep it useful |
|---|---|---|
| Issued plan set | Approved dimensions, assemblies, systems, and code details | Identify the issue date and archive superseded sheets. |
| Contract and scope | Commercial agreement, responsibilities, inclusions, exclusions, and payment terms | Reference the plans and define broad phrases in plain language. |
| Specifications and selections | Products, finishes, fixtures, allowances, and substitutions | Record model, finish, quantity, approver, and decision date. |
| Change orders | Approved change to scope, price, or time | State the reason, effect, and approval before affected work proceeds. |
| Inspection records | Agency checks at required stages | Save results and correction notices with the relevant plan reference. |
| Closeout file | Final records, warranties, manuals, and unresolved follow-up | Build it during construction instead of reconstructing it at the end. |
The owner does not need to act as superintendent. Be able to identify the current documents, open decisions, and next acceptance point. Add decisions made by phone or text to the project record.
How should homeowners compare ADU construction proposals?
Compare proposals on the same scope, not only on the total at the bottom. Two totals may describe different projects. One may include design coordination, utility trenching, finish allowances, restoration, and closeout. Another may leave those items open or place them in an exclusion list. A lower initial total is not a savings if essential work has only been deferred.
Separate confirmed scope from allowances and unknowns. An allowance should state what it covers and what happens if the final selection differs. Pair an unknown condition with an investigation step or a written pricing method instead of disguising it as an allowance.
| Comparison lens | What to look for | Question to ask |
|---|---|---|
| Design and permit coordination | Named responsibility from drawings through corrections | Who owns a conflict between the plan and field condition? |
| Site work | Access, protection, excavation, disposal, utilities, and restoration | Which site activities are included, excluded, or still unknown? |
| Fixtures and finishes | Specific products or transparent allowances | What selection deadline protects the schedule? |
| Inspections | Scheduling, correction response, and documentation responsibility | Who confirms that work can be covered after a checkpoint? |
| Changes | Written price and time effect before authorization | Who can approve a change and where is approval recorded? |
| Closeout | Punch, final records, care information, and warranty routing | What must be delivered before the project is considered complete? |
Use the CSLB license lookup to verify the contractor information you are relying on. Then ask for a written explanation of responsibilities, not just a company label. L Square's current service ownership and project paths are summarized on the ADU construction services page. Current planning ranges and cost drivers live on the separate Orange County ADU cost guide.
What should be decided before the first construction day?
- Confirm access and protection
Identify the worker entrance, delivery route, staging area, protected landscaping and hardscape, dust controls, temporary barriers, working-hour expectations, and end-of-day cleanup.
- Mark the work boundary
Review demolition and excavation limits in the field. Clarify which surfaces, utilities, structures, and personal areas must remain undisturbed.
- Resolve early selections
Approve items that affect openings, framing, rough plumbing, rough electrical, ventilation, equipment locations, waterproofing, or long-lead ordering.
- Set the decision calendar
Give each remaining owner decision a due date, an approver, and a short description of what waiting would affect.
- Agree on documentation
Decide where current plans, updates, photos, inspection results, selections, and changes will be stored.
- Define the escalation path
Name the person who explains a field conflict, prepares a written option, and obtains authorization before affected work continues.
Confirm how the occupied property will function. The schedule should identify planned utility shutdowns and access changes before they happen.
What should an owner check during site, utility, and foundation work?
Early site work creates conditions that later layers can hide. Excavation exposes soil and access constraints. Trenches establish utility routes. Forms set edges and elevations. Reinforcement, sleeves, and penetrations occupy the future concrete zone. The owner should understand the planned checkpoint before backfill or concrete, not try to diagnose the work from a photograph after it is covered.
Ask four questions: What was installed? Which drawing controls it? What was inspected or accepted? What covers it next? This creates a useful record without asking the owner to direct trades.
| Visible phase | Team checkpoint | Owner record |
|---|---|---|
| Protection and layout | Work limits, access, staging, and reference points agree with the plan | One overview photo and any approved field clarification |
| Excavation and trenching | Routes, depths, conflicts, and required checks are resolved before cover | Photos labeled by location and purpose |
| Forms and reinforcement | Geometry, penetrations, embeds, and pre-pour requirements are ready | Pre-pour status and inspection result |
| Concrete placement | Approved placement is complete and protected for the next stage | Date, area, and any follow-up item |
| Drainage and restoration | Water movement and disturbed surfaces follow the approved scope | Open restoration items carried to punch |
What should an owner check during framing, rough-ins, and enclosure?
Framing is where the room becomes understandable. Window and door openings, ceiling shape, wall thickness, equipment clearances, and built-in locations become physical. This is the best time to compare the visible structure with the current plan and approved changes. It is not the time to redesign casually, because a small-looking field request can affect engineering, energy details, waterproofing, electrical routes, ordering, and inspections.
Review rough mechanical, electrical, and plumbing work before insulation and drywall conceal it. Confirm selections affecting valves, lighting, switching, appliances, ventilation, and equipment. Label concealed-work photos by room, wall, and purpose so they remain useful later.
A completed L Square project in Pasadena shows why framing decisions matter beyond structure. The vaulted ceiling, clerestory relationship, lighting, insulation path, and mechanical placement had to coordinate before the room was closed. See the full Pasadena ADU project and the Rosemead two-story ADU project for two different design and construction paths.
How should inspections and concealed-work records be handled?
Inspection names and order vary, so the issued permit and local agency instructions should control the project-specific list. Common checkpoints may involve underground work, foundation or pre-pour conditions, framing, rough systems, insulation, wallboard, and final work. The important management principle is stable: do not cover work that still requires an inspection, correction, design answer, or documented acceptance.
State ADU law requires ministerial rather than discretionary approval processes for covered ADUs. Government Code section 66316 requires ministerial provisions and makes a noncompliant local ordinance null and void until corrected. That rule does not replace inspections. Use the local permit record for field requirements.
- Confirm the applicable inspection or acceptance step has been identified.
- Resolve open corrections and design questions that affect the area.
- Record approved field changes against the current plan or detail.
- Capture labeled photos when they will help future maintenance or verification.
- State who has authorized the next covering activity.
If an inspection produces a correction, record the correction itself, the responsible person, the planned response, and the result of the follow-up. Avoid treating a verbal "looks fine" as a substitute for the agency record.
How should selections and change orders be controlled?
A change may come from an owner selection, discovered condition, unavailable product, or agency comment. The safeguard is a consistent written process.
A useful change order explains the existing contract reference, the requested or discovered change, the reason, the exact scope effect, the price effect, the time effect, and the approval needed. It should also identify whether affected work must pause. If the change alters the approved design, the project team should determine whether design or agency review is required before construction continues.
| Change record | Minimum useful detail | Why it matters |
|---|---|---|
| Trigger | Owner request, field condition, product issue, design coordination, or agency comment | Separates preference changes from discovered conditions. |
| Scope | What is added, removed, relocated, substituted, or repaired | Prevents a price from floating without a defined result. |
| Documents | Plan, sketch, specification, selection, or photo reference | Connects the change to information the team can build from. |
| Price | Added cost, credit, or no-cost statement | Makes the budget effect visible before authorization. |
| Time | Decision deadline and expected schedule effect | Shows whether waiting or rework affects the sequence. |
| Approval | Authorized person, date, and written acceptance | Creates one reliable direction for the field team. |
Selections need a similar record. Document exact product information and accepted substitutions. The record should be specific enough to order and install.
What should be checked during finishes and commissioning?
As walls close and finishes arrive, the owner's attention shifts from hidden coordination to visible quality and operation. Keep the review organized by room or system. Random walk-through comments are easy to lose; a single punch list with location, issue, responsible person, and status is easier to close.
Commissioning confirms that installed systems operate and that the owner knows the controls. Checks depend on the project and may include plumbing, drainage, hot water, electrical devices, lighting, ventilation, heating and cooling, openings, locks, appliances, and alarms.
| Area | Review focus | Closeout record |
|---|---|---|
| Plumbing | Operation, visible leaks, drainage, fixture stability, and access | Issue list plus applicable manuals and warranty information |
| Electrical and lighting | Devices, controls, labels, fixtures, and owner-selected functions | Panel information and control instructions where applicable |
| Mechanical and ventilation | Startup, controls, airflow, filters, and maintenance access | Model information, manuals, and service contact path |
| Windows, doors, and hardware | Operation, latching, weather seals, screens, and finish condition | Room-by-room punch status |
| Cabinets, counters, tile, and flooring | Installation, alignment, transitions, sealants, and visible damage | Accepted repair or replacement list |
| Exterior and site | Drainage, penetrations, finishes, cleanup, access, and restoration | Final exterior punch and maintenance notes |
Do not wait for the final hour to begin the punch list. Start it when finishes become reviewable, update it as items close, and distinguish cosmetic work from items that affect operation, safety, inspection, or weather protection.
What belongs in ADU punch, closeout, and warranty handoff?
Completion is a set of verified outcomes, not only a final cleaning. The contract should define the commercial completion terms, while the project closeout file should make the finished unit understandable to the owner. Collect records as they become available so the final handoff is a review, not a search.
- Approval records: applicable final inspection or agency records available to the project.
- Current documents: approved plans and documented changes retained in one place.
- Punch status: each item marked open, scheduled, accepted, or otherwise resolved.
- Equipment information: model details, manuals, controls, filters, and maintenance intervals.
- Product records: warranties, care instructions, finish information, and spare materials included in the scope.
- Keys and access: doors, windows, locks, remotes, and service access reviewed.
- Warranty routing: one contact method, reporting expectations, and emergency boundaries explained.
During the handoff, walk through the unit as an operator. Ask how to shut off water, use heating and cooling controls, reach serviceable components, replace filters, care for finishes, and report a warranty concern. Record unresolved items and their next date. A clear closeout protects both the owner and builder because expectations remain visible after the active jobsite winds down.
Where should an owner go for the next project-specific answer?
This checklist organizes questions; it does not decide what a particular lot can support or what a particular contract includes. Review the broader ADU planning guide, compare the design-build process, and use the ADU cost guide for current L Square planning information. Real construction and completed examples are collected in the L Square ADU project gallery.
What are the most common ADU construction checklist questions?
What should be complete before ADU construction starts?
Which ADU plans should the field team use?
How should I compare two ADU construction proposals?
What should be photographed before work is covered?
Can work continue before an inspection correction is closed?
What should every ADU change order include?
How often should an owner receive construction updates?
When should the ADU punch list begin?
What documents should I receive at ADU closeout?
Does this checklist replace the contractor, architect, engineer, or building department?
Reviewed sources: California HCD's current ADU Handbook, California Government Code section 66316, CSLB's contractor license lookup, the issued project documents for a specific property, and the linked L Square owner pages. Laws, forms, and local procedures can change; verify current official material before relying on it for a project decision.
This checklist is the spine; the detail lives in the neighbouring guides. Permit requirements covers what goes into the submittal, the foundation walkthrough shows the first construction stage in photographs, the utilities guide covers the connections that decide the budget, and the timeline guide attaches real durations to each phase.