Construction contracts, permit applications, and contractor conversations are full of industry jargon. This glossary defines the terms Los Angeles homeowners most commonly encounter during remodeling, ADU construction, room additions, and new construction projects — in plain language, without the fluff.
A secondary residential unit on the same lot as a primary home. In Los Angeles, ADUs can be detached new construction, attached additions, garage conversions, or interior conversions. California law allows up to one ADU and one JADU on a single-family lot. ADUs can be rented independently from the primary home.
A permit obtained after construction is already complete — for work that was done without a permit. As-built permits require exposing completed work for inspection and often cost double the standard permit fee. In Los Angeles, getting an as-built permit for an unpermitted garage conversion typically requires opening walls and may result in a demolition order if the work doesn’t meet code.
The licensed architect who stamps and is responsible for the construction drawings submitted to the building department. Required for certain project types and jurisdictions. For most ADU and remodel projects in LA, a licensed designer or drafter (not a full architect) is sufficient.
A wall that carries the structural load of the building above it down to the foundation. Removing a bearing wall requires engineering and a structural permit. Many homeowners discover their open-concept remodel requires a beam installation and temporary shoring when a bearing wall is removed.
The physical barrier between the interior and exterior of a structure — including walls, roof, windows, and foundation. In Los Angeles, improving the building envelope (insulation, windows, weather sealing) is required when adding conditioned space, per Title 24 energy code.
Official permission from the local building department to perform construction. Required for most structural, electrical, plumbing, and mechanical work. In Los Angeles, LADBS issues permits for the City of LA; independent cities (Pasadena, Glendale, Burbank, Santa Monica, etc.) have their own permit offices.
A document issued by the building department after a final inspection confirms the completed construction meets all applicable codes. Required for ADUs before they can be legally occupied and rented. An ADU without a C of O cannot be listed on Zillow, Airbnb, or any rental platform legally.
A written modification to the original construction contract — adding scope, removing scope, or changing specifications. Every change order should document what changed, why, and what it costs. The most common contractor dispute in LA involves undisclosed change orders that weren’t agreed to in writing before work proceeded.
Interior space that is heated and/or cooled — as opposed to garages, attics, and crawl spaces. All conditioned space must meet California Title 24 energy standards. Converting a garage to an ADU turns unconditioned space into conditioned space, triggering energy compliance requirements.
California’s licensing authority for contractors. Verifiable at cslb.ca.gov. Any contractor performing work over $500 must hold a valid CSLB license. You can check a contractor’s license status, classification, disciplinary history, and insurance coverage at cslb.ca.gov. APLA’s license: CA #1136359.
The removal of existing structure, finishes, or systems to prepare for new construction. Selective demo (removing specific walls, cabinets, or tile) is the first phase of most remodeling projects. Full demo refers to removing a structure entirely.
A project delivery method where one contractor handles both design (drawings, plans) and construction. Eliminates the gap between the architect’s vision and what the contractor can build. APLA operates as design-build for most ADU and remodeling projects.
Wood decay caused by fungus that thrives in moisture-damaged areas. Common in Los Angeles homes near plumbing leaks, window frames, and subfloor areas. Often discovered during demo. Dry rot must be fully removed and replaced before new finishes are applied.
Panels made of gypsum plaster sandwiched between paper sheets — the most common interior wall finish in residential construction. Installed after framing and mechanical rough-in are complete. Fire-rated drywall (Type X) is required in certain locations, including garage walls adjacent to living space.
A means of exit from a building or room in an emergency. Building code requires that every sleeping room have at least one egress window with minimum opening dimensions. ADUs must have proper egress. Basements converted to living space require an egress window or door.
The distribution board that receives electricity from the utility and distributes it to circuits throughout the home. A 200-amp panel is standard for most Los Angeles homes. ADU additions or major remodels often require a panel upgrade from 100A or 150A to 200A.
The ratio of total building floor area to lot size — a zoning metric that limits how much can be built on a given lot. Los Angeles zoning ordinances set FAR limits by zone. Your ADU or addition may be limited by FAR even if it otherwise meets setback requirements.
The last building department inspection before a Certificate of Occupancy is issued. Inspectors verify all work matches the approved plans and meets code. A failed final inspection requires corrections before re-inspection.
The widened base of a foundation that distributes structural loads to the soil below. Continuous footings run along the perimeter of a building; pier footings support individual posts or columns. Footing design is determined by a structural engineer based on soil conditions and building loads.
The structural base of a building that transfers loads to the ground. Residential foundations in LA include: slab-on-grade (concrete poured directly on soil), raised foundation (perimeter walls with crawl space), and basement. Many older LA homes have unreinforced masonry foundations that require seismic retrofitting.
The structural skeleton of a building — the wood (or steel) beams, studs, and joists that define walls, floors, and roof structure. In residential construction, standard framing is 2×4 or 2×6 lumber. Framing inspection happens before drywall is installed.
A licensed contractor who manages the full scope of a construction project — coordinating subcontractors (electricians, plumbers, framers), scheduling inspections, managing the permit, and delivering a complete project. In California, a Class B license is the General Contractor classification. APLA holds CA General Contractor License #1136359.
An engineering report assessing soil conditions on a building site. Required for hillside properties, properties with expansive soils, and most ADU projects in hillside zones of Glendale, Pasadena, and the Hollywood Hills. The report informs foundation design.
The direct costs of construction — labor and materials. Distinguished from soft costs (design, permits, engineering fees). In an LA remodeling budget, hard costs typically represent 65–80% of total project cost.
A governing body for a residential community that enforces CC&Rs (Covenants, Conditions, and Restrictions). California AB 3182 prohibits HOAs from banning ADUs. HOAs can still regulate the design and appearance of ADUs but cannot prevent them entirely.
Fees charged by cities to offset the infrastructure cost of new development. For ADUs under 750 sq ft in California, state law prohibits impact fees. For ADUs 750 sq ft and larger, fees must be proportional to the ADU’s size relative to the primary home.
Reviews by city building inspectors at key stages of construction to verify compliance with approved plans and building code. Standard inspection sequence: foundation, framing, rough plumbing, rough electrical, HVAC rough-in, insulation, drywall, and final.
A secondary unit of up to 500 sq ft created entirely within the footprint of the existing primary home. Requires its own entrance and efficiency kitchen. Shares utilities with the primary home. Less expensive to build than a full ADU but also smaller and less rentable.
The permit authority for the City of Los Angeles. Covers most of the San Fernando Valley, Hollywood, West LA, and central LA. Does NOT cover independent cities like Pasadena, Glendale, Burbank, Santa Monica, or Culver City — those cities have their own building departments.
A legal claim against a property for unpaid work or materials. Subcontractors and suppliers in California can file a mechanic’s lien if they are not paid. Homeowners can protect themselves by requiring lien releases from all contractors and subcontractors upon payment.
The three primary building systems that run through walls and ceilings. MEP rough-in inspection happens before insulation and drywall. MEP work requires licensed subcontractors (electrician, plumber, HVAC contractor) and permits for most projects.
A payment structure tied to completed stages of construction rather than dates or percentages. California law limits initial deposits to 10% or $1,000 (whichever is less). Subsequent payments should track actual completed work. APLA uses milestone-based payments on all projects.
Pre-approved ADU designs that some LA-area cities maintain to accelerate the permit process. Los Angeles County and some cities offer pre-approved ADU plan libraries where homeowners can select a design and skip the plan check entirely, cutting permit time significantly.
The building department’s review of submitted construction drawings for code compliance. LADBS targets 45–70 days for ADU plan checks; most kitchen and bath remodels are faster. Plan check corrections (a list of required revisions) must be addressed before a permit is issued.
A list of minor remaining items to be completed before final payment and project closeout. Typical punch list items: touch-up paint, hardware installation, fixture adjustments, door alignment. A clean punch list and signed completion document should precede the final payment.
A measure of insulation’s resistance to heat flow. Higher R-value = better insulation. California Title 24 energy code requires minimum R-values for walls, ceilings, and floors depending on climate zone. Los Angeles (Climate Zone 9) has specific R-value requirements that affect ADU and addition design.
A wall built to hold back soil — common on hillside properties throughout the Hollywood Hills, Bel Air, Glendale, and Pasadena. Retaining walls over 4 feet in most LA jurisdictions require a structural permit. Failure to permit a retaining wall is a red flag that surfaces at home sale.
The minimum required distance between a structure and the property line, street, or another structure. State ADU law limits cities to requiring only 4-foot rear and side setbacks for new detached ADUs. Standard setback requirements apply to all other construction types.
A wall designed to resist lateral forces (earthquakes, wind) in a building. Common in seismic retrofitting projects and required in new construction throughout California. Adding windows or doors to a shear wall location requires engineering review.
A building configuration where one floor is significantly weaker than the floors above it — typically a ground floor with large garage openings. Los Angeles has an active soft-story retrofit ordinance affecting thousands of multi-family buildings. Residential garage conversions are evaluated for soft-story risk.
A specialty trade contractor hired by the general contractor to perform specific work: electrical, plumbing, framing, tile, flooring, etc. Licensed GCs coordinate and are responsible for all subs on the project. Homeowners should not pay subs directly — all payments flow through the GC.
California’s Building Energy Efficiency Standards — the energy code that applies to all new construction and permitted alterations in California. Title 24 requirements affect insulation R-values, window U-factors, HVAC equipment efficiency, and lighting. Compliance is required for ADUs, additions, and any permitted remodel.
A detailed written description of everything a contractor will do, using what materials, to what specifications. An itemized scope of work is the most important document in any construction contract — it defines accountability and eliminates ambiguity about what is and is not included.
A general contractor (GC) manages the entire project — permits, scheduling, coordinating trades, and delivering a complete result. Subcontractors are specialty trade workers (electricians, plumbers, framers, tile setters) hired by and accountable to the GC. Homeowners hire the GC; the GC hires subs.
Submitting a permit application to the building department and obtaining official approval to perform construction. The contractor “pulls” the permit — meaning they take legal responsibility for the work being performed to code and inspected. This is done before construction begins.
A C of O is the final document the building department issues after confirming completed construction meets all applicable codes. Yes — an ADU absolutely requires a Certificate of Occupancy before it can be legally occupied or rented. An ADU without a C of O is legally unpermitted regardless of how nice it looks.
APLA Construction handles every phase of residential and commercial construction in Greater Los Angeles — from design and permits through final inspection and Certificate of Occupancy.
Call: (818) 818-4419
Email: info@aplaconstruction.com
CA General Contractor License #1136359
ADU Construction | Home Remodeling | Room Additions