The vocabulary of architectural real estate comes from three worlds that rarely sit at the same table: preservation law, the building trades, and the transaction itself. I have worked in two of them directly. I built custom homes from 1978 to 1998, with a specialty in finish carpentry, and I have been a REALTOR since 1990. This glossary defines the terms that come up when San Gabriel Valley buyers, sellers, and owners deal with architecturally significant homes, in plain language, with the legal terms traced to the programs that define them.
One note on scope. The eleven architectural styles that define the SGV’s inventory, Craftsman through Queen Anne Victorian, are not defined here. Each style has its own full reference page on this site, covering origin, defining features, signature architects, and the local concentration record. A fifty-word entry would shortchange them. This glossary covers everything else: the designation programs, the construction vocabulary, the transaction terms, and the data terms behind the market analysis published here.
Designation and preservation programs
National Register of Historic Places (NRHP). The federal government’s official list of districts, sites, buildings, structures, and objects significant in American history, architecture, archeology, engineering, and culture. Created by the National Historic Preservation Act of 1966 and administered by the National Park Service. For a private owner, listing is largely honorary: on its own, it places no restrictions on what an owner does with private funds. Obligations arrive only through local designation, federal involvement in a project, or acceptance of certain benefits.
National Historic Landmark (NHL). A separate and higher federal designation reserved for properties significant to the history of the entire nation, not just a community or state. Roughly 2,600 properties nationwide hold the designation, and every NHL is automatically listed in the National Register. The Gamble House in Pasadena is a National Historic Landmark.
Historic district. A defined geographic area recognized for historic significance, made up of contributing and non-contributing properties. The term covers two different things: districts listed in the National Register, which are federal recognition, and districts designated by a city under its own ordinance, which carry local review authority. The same neighborhood can hold both, and in Pasadena some do.
Contributing property. A building, structure, object, or site within a designated district whose character and features relate to the district’s historic significance. Its opposite is a non-contributing property, one that stands inside the boundary without adding to the historic character. The status matters: a contributing property in a National Register district qualifies for benefits available to individually listed properties, and in many cities contributing status opens the door to incentives such as the Mills Act. Major alterations can move a property from contributing to non-contributing.
Landmark district. Pasadena’s local designation for a grouping of contiguous properties with citywide significance, created under Chapter 17.62 of the municipal code. A minimum of 60 percent of the properties inside the boundary must qualify as contributing. Designation puts exterior work visible from public streets through a design review process. Bungalow Heaven became Pasadena’s first Landmark District in 1989. Neighboring cities run their own versions of local designation under their own ordinances.
Local landmark. An individual property designated by a city for its historic, cultural, or architectural significance under the city’s preservation ordinance. Local landmark status is the designation that typically carries real review authority over exterior changes, and in most participating cities it is a qualifying path to a Mills Act contract.
Mills Act. A California law that lets participating cities and counties lower the property taxes on a qualified historic property in exchange for the owner’s binding commitment to restore and maintain it.
The mechanics, under the 1972 statute: the owner signs a contract with the city, the county then assesses the property by an income method rather than the market method, which generally lowers the tax bill, and the contract runs a minimum of ten years, renews automatically each year, and transfers with the property when it sells. Terms, eligibility, and program caps vary city by city, so the local planning department is always the first call. Pasadena’s version, the Historic Property Contract Program, was established in 2002 under Mills Act authority.
Preservation easement. A recorded legal agreement that permanently protects a historic property’s character-defining features by giving a preservation organization the right to review changes to them. Unlike a Mills Act contract, which runs in renewable terms, an easement is written into the deed and binds every future owner. Pasadena Heritage holds more than eighty preservation easements, a program it describes as the largest west of the Mississippi.
California Register of Historical Resources. The state-level counterpart to the National Register, established under the California Public Resources Code. It is the authoritative state listing of buildings, sites, structures, objects, and districts significant in California history, and listing on it is one of the qualifying paths cities use for local incentive programs.
Certificate of Appropriateness. The approval a designated property typically needs before exterior alterations, issued through the local design review process. The name and process vary by city, but the principle is constant: in a designated district or on a designated landmark, publicly visible exterior work is reviewed against the district’s guidelines before a permit issues.
Secretary of the Interior’s Standards. The federal benchmark for how work on historic buildings should be done, published by the National Park Service. The Standards define four distinct treatments: preservation, rehabilitation, restoration, and reconstruction. Mills Act contracts, tax credit projects, and most local design guidelines measure proposed work against these Standards.
Historic integrity. The degree to which a property still physically conveys its period. The federal criteria evaluate integrity through seven aspects: location, design, setting, materials, workmanship, feeling, and association. Integrity is not condition: a worn house that keeps its original fabric can hold high integrity, while a freshly renovated one can have little left. That distinction is why two houses of identical age and style can carry very different designations.
Period of significance. The span of years during which a property or district gained the significance that justifies its designation. Inside a district, contributing properties are generally those built during the period of significance that still convey their appearance from it.
Architecture and construction vocabulary
Period-correct. Consistent with the materials, methods, proportions, and detailing of the era in which the house was built. A period-correct repair uses what the original builder would have used, or the closest available equivalent. The term is the working standard for evaluating whether past work on a house respected it or erased it, and it is where a builder’s eye earns its keep: the difference between period-correct and merely old-looking sits in the joinery, the profiles, and the materials.
Original fabric. The physical material that survives from a house’s construction: the framing, plaster, flooring, millwork, glass, hardware, and cladding the builder installed. Fabric is what integrity is made of. Every question about restoration, designation, and authenticity eventually comes down to how much original fabric remains and what condition it is in.
Millwork. The shaped wood elements of a house produced at a mill: casings, baseboards, crown molding, window and door parts, paneling, stair parts, and built-in cabinetry. In pre-war SGV homes the millwork is a defining feature, and original millwork in original condition is one of the strongest signals of an intact house.
Finish carpentry. The final stage of carpentry, the visible woodwork: hanging doors, setting casings and baseboards, running crown, building stairs and built-ins. It is the trade that installs and repairs millwork, and it was my specialty during my building years. In an architectural home, the quality of the finish carpentry is where authenticity is easiest to read and hardest to fake.
Character-defining features. The visual and physical elements that give a historic property its identity: the porch, the windows, the roofline, the cladding, the interior millwork, the floor plan itself. Preservation review focuses on these features, and thoughtful ownership starts with knowing which features carry the house’s character before changing anything.
Deferred maintenance. Upkeep that has been postponed rather than performed: the unpainted siding, the unserviced furnace, the roof past its life. It is distinct from damage and from defect, but in an older home it compounds quietly, and the cost of catching up is a real number that belongs in any offer on a house that shows it.
Bungalow court. A grouping of small detached bungalows arranged around a shared courtyard, a housing type that originated in Pasadena. St. Francis Court, designed by Sylvanus Marston in 1909, was the first bungalow court in Pasadena, and the type became one of Southern California’s signature contributions to American housing.
Ultimate bungalow. The largest and most fully realized Craftsman commissions, where the bungalow vocabulary was executed at estate scale with total design integration, down to the furniture and fixtures. The Greene and Greene houses in Pasadena, the Gamble House among them, are the defining examples.
Provenance. The documented history of a property: who designed it, who built it, who owned it, and what was done to it over time. For architectural homes, provenance is the paper trail, permits, drawings, photographs, and archives, that turns a story about a house into a fact about it.
Attribution versus documented authorship. An attributed house is credited to an architect on stylistic or circumstantial evidence. A documented house is proven, by original permits, drawings, contracts, or archival records, to be that architect’s work. The two are not the same claim, they do not deserve the same confidence, and they do not command the same value. Honest listings and honest analysis say which one they mean.
Restoration, rehabilitation, and remodel. Restoration returns a property to its appearance at a particular period, removing later work. Rehabilitation keeps a property in use while preserving its historic character, allowing compatible alteration. A remodel simply changes the house to suit the current owner, with no preservation standard implied. The three words are often used interchangeably, and they should not be: which word a listing uses, and whether the work matches the word, tells a buyer a great deal.
Transaction terms
CRMLS. California Regional Multiple Listing Service, the database through which the large majority of SGV listings are published and shared among brokers.
Two of its structural features matter for architectural homes. CRMLS does not enforce an architectural style field, so style attribution in listings is only as good as the agent writing it. And its data licensing restricts how hyperlocal data can be republished, which is why serious hyperlocal data access runs through a broker relationship.
MLS remarks. The free-text description an agent writes for a listing. Because no style field is enforced, the remarks are where architectural identity lives or dies in the data, and they routinely underspecify or misname it. A Spanish Colonial Revival labeled Mediterranean, or a Craftsman labeled simply as vintage, is found and corrected by literacy, not by search filters.
Escrow. The neutral third-party process that holds funds and documents while a sale’s conditions are satisfied. In Southern California practice, opening escrow follows an accepted offer, and closing escrow is the moment ownership and money actually change hands.
Contingency. A condition written into a purchase agreement that must be satisfied or removed before the sale closes, commonly covering inspection, appraisal, and financing. For architectural homes, the inspection contingency carries extra weight: the period systems, materials, and any designation obligations deserve specialist attention within the contingency window.
As-is sale. A sale in which the seller offers the property in its present condition and is not agreeing to make repairs. What as-is does not do is waive disclosure: California law is explicit that the required Transfer Disclosure Statement cannot be waived in an as-is sale, and a seller must still disclose known material defects. As-is limits repair expectations. It never licenses concealment.
Comparables. Recently sold properties similar enough to a subject property to inform its value. Architectural homes strain the standard approach, because style, architect attribution, integrity, and designation status all move value in ways square footage does not capture. A comparable that shares the bedroom count but not the architectural identity is a weak comp.
Days on market (DOM). The number of days between a listing going active and going under contract or off market. Definitions and reset rules vary by MLS, which is why any days-on-market figure should name its source and method before it is trusted.
Seller disclosures. The documents through which a California seller tells a buyer what they know about the property’s condition and history. For designated properties, disclosure of the designation and any contract obligations, such as a Mills Act contract that transfers with the sale, is part of a clean transaction.
Data and methodology terms
Empirical probability. A probability computed from observed outcomes rather than from assumption or theory. If a question is how likely a home like this is to sell under given conditions, the empirical answer comes from counting what actually happened across comparable attempts.
This is the foundation of the Sell Odds engine: probabilities built from recorded sold and unsold outcomes.
Outcome data. Records of what happened to listings, both the sales and the failures. Most market statistics describe only successful sales. Outcome data includes the listings that expired or were withdrawn, which is precisely the information a seller pricing a home needs, because the risk of not selling is invisible in sold-only data.
Curated sample. A set of properties hand-identified for analysis against stated criteria, with the sample size disclosed, used where no reliable data field exists. Style-level market analysis works this way by necessity: because CRMLS enforces no style field, properties must be identified by professional judgment, and honest analysis says so and shows its sample size.
Median. The middle value of a data set, with half the observations above and half below. Market analysis here favors medians over averages because housing data carries outliers, and a single estate sale can drag an average far from what a typical seller should expect. When a figure on this site is a median, it is labeled as one.