US homes by city architecture for mansion buyers: six cities

US homes by city architecture reads better in a fixed order: massing, roof, openings, materials, then ornament. Most people identify a house by its ornament, the part most likely to have been added, removed, or copied.

Better evidence is coarser and harder to fake: the shape of the mass, the roof line, the rhythm of openings, and the wall material. Work in that order and you can place a house without knowing a single name.

The order matters most with big houses, where the ornament is thickest and the sales copy is loudest. Whether you are on a mansion tour or weighing a very large old house you might buy, the mass, roof, openings and wall material are what will still be there in thirty years. The trim is the part a previous owner chose.

What to take away

Read a house in five passes

The systematic version of this, walking a building at three distances and asking what each one shows, is set out in Preservation Brief 17 on identifying visual character.

Massing. Stand back far enough to see the whole block. Is it a single simple volume, or a main body with wings? Is it wider than it is tall, or the reverse?

Is the composition symmetrical about the entrance, or deliberately picturesque with parts of different heights? Symmetry about a central door is a formal tradition; an off-center entrance under a projecting gable belongs to a different one.

Roof. The roof carries more information per glance than any other element. Note the pitch, whether it is steep enough to shed snow or shallow enough to be nearly invisible from the street.

Note the shape: a simple gable, a hip sloping on all four sides, a gambrel with two pitches, a mansard with a near-vertical lower slope full of windows.

Note the overhang, since deep eaves with exposed rafter ends mean something different from a roof cut flush at the wall. Note where the roof stops: a parapet hiding a flat roof is a different building culture from a projecting cornice.

Openings. Count the windows across the front and look at the spacing. Even spacing suggests rooms of similar size behind a corridor or a central hall. Grouping, with a wide opening in one bay and narrow ones elsewhere, suggests the plan is being expressed rather than hidden.

Then look at the proportion of each opening, the number of panes, and whether the glass sits deep in the wall or close to its face. Deep reveals mean a thick load-bearing wall. Flush windows usually mean a thin skin over a frame.

Materials. Ask what the wall is really made of, not what it looks like. Brick laid in a pattern that includes headers is doing structural work; brick in a single repeating stretcher pattern is often a facing.

Stone can be cut and coursed, or rough and random, and the difference is money and intent. Wood siding varies by board width and profile. Stucco hides whatever is behind it, so look at window reveals and corners to guess the substrate.

Details. Only now look at columns, brackets, porches and trim. Ornament tells you what the house wanted to be. The four passes before it tell you what it is.

What the combinations usually mean

None of these are proof on their own. A house can carry a steep roof and classical trim because it was altered, or because its builder liked both. Treat each observation as evidence and look for agreement across the five passes.

Why the same style looks different in different cities

Style travels through pattern books, magazines and trained architects. Materials do not travel nearly as well, and climate does not travel at all. So a style arrives, and then local conditions bend it.

Where good building stone is close by, walls get thicker and openings smaller. Where timber is abundant and cheap, the same style appears in wood with the stone details reproduced in painted boards. Where clay is local, brick dominates and the ornament migrates into brickwork patterns.

Where snow load is serious, roofs steepen. Where summer heat is the problem, porches deepen, ceilings rise and windows are placed to cross ventilate. Where lots are narrow, the whole composition turns to face the short end.

Two houses in different cities can belong to the same family and share almost no surface material. Plan logic and massing survive the journey; the skin does not.

This also explains why a regional survey is more useful than a national one. The mapped comparisons are on the US homes by city map.

Comparative material is easier to find than most people expect. The architectural survey photographs held by the Library of Congress include elevations and details recorded to a consistent standard, which makes them useful for training your eye on the differences rather than the similarities.

Six cities: what to keep and what to drop

Each city below gets a keep list and a drop list. The keep list is the structure and fabric a review board will defend; the drop list is what is most often done to these houses and is hardest to reverse. On a tour, or before you make an offer on a house in one of these districts, start with the keep list.

Boston, Massachusetts

Back Bay rowhouses went up on filled marshland between roughly 1860 and 1900, in brick with bow fronts, mansard roofs and heavy cornices. Triple-deckers, the wood-frame three-unit buildings of Dorchester, Roxbury and Somerville, arrived between about 1880 and 1930.

Keep the brick sidewalls, the slate mansard and the stacked wooden porches. Drop vinyl siding laid over original clapboard, and railings swapped for vinyl. The Back Bay Architectural Commission reviews exterior changes inside the district.

The Back Bay also shows where district rules stop. The Boston Landmarks Commission's study report on the Frederick Ayer Mansion at 395 Commonwealth Avenue calls it the last surviving example of a complete and in situ residential commission by Louis Comfort Tiffany. Its exterior is protected by the landmark district guidelines of the Back Bay Architectural District, but the report notes that the interior remains vulnerable to change, which is why a petition asked the Commission to designate the Tiffany-designed interior spaces as well. For a buyer, district review covers the facade, not the rooms.

Charleston, South Carolina

The single house is the city's best-known plan: one room wide and three deep, set sideways to the street, with a two-story piazza facing south or west. The 1886 earthquake left brick walls stitched with tie rods and star plates, known as earthquake bolts.

Keep the piazza, the shutters, the raised basement and the earthquake bolts. Drop the enclosure of a piazza into an interior room, and vinyl sash on the front wall. The Board of Architectural Review governs the Old and Historic District; the city records that the BAR was established in 1931 with the creation of the first preservation ordinance in the United States.

Santa Fe, New Mexico

Santa Fe took Pueblo Revival as its civic image in the early 20th century, and a city ordinance dating to 1957 fixed flat roofs, earth-tone colors and rounded parapets in the historic districts.

Keep real vigas and latillas, canales that carry roof water through a parapet, and recessed portales. Drop foam viga ends glued to a flat wall, and asphalt shingle edges showing above a parapet. The Historic Districts Review Board reviews exterior work.

Chicago, Illinois

Two house types define the residential city. The greystone is an Indiana limestone veneer over brick, and the bungalow is brick with wide overhanging eaves and masonry piers. Tens of thousands of bungalows went up in the region between about 1910 and 1940.

Keep the limestone face, the brick piers, the wide eaves and the raised basement entry. Never paint greystone. Drop the enclosed front porch, which removes the sheltered outdoor space the plan was built around.

The Commission on Chicago Landmarks reviews proposed exterior work on designated Chicago landmarks and landmark districts, and that review is part of the city's permit process under the Chicago Landmarks Ordinance.

San Francisco, California

Rowhouses on narrow lots share sidewalls and push their front rooms into projecting bays, which is how Victorian and Edwardian blocks in Pacific Heights and the Western Addition get their light. Sunset and Richmond houses, built from the 1920s into the 1940s, put the garage at grade with a stucco sunroom above it.

Keep the projecting bay, the wood double-hung sash and the original garage opening. Drop vinyl replacement windows, and any remodeling that flattens the bay. Exterior work in a city landmark district needs a certificate of appropriateness from the Planning Department.

New Orleans, Louisiana

The shotgun is one room wide with no hallway, rooms in a line from front to back, raised on brick piers with a gallery under the roof extension. A camelback adds a partial second story at the rear. Most went up between about 1850 and 1920.

Keep the raised foundation, the gallery roof, the tall narrow windows and the shutters. Drop the enclosure of the front gallery into living space, and brick veneer laid over the original wood frame. The Historic District Landmarks Commission reviews exterior changes.

Read the review boards the same way in all six cities: they decide whether a new owner may change the exterior at all. Ask the board's staff what has already been approved at an address before you buy, and what a new owner would need to file. The architecture is what you are buying; the board sets the limit on what you can do to it.

Common questions

How do I date a house from the outside?

You usually cannot date a building to a single year. Be suspicious of anyone who claims otherwise from a photograph. Instead, place it in a sequence: which parts are earliest, what was added, and what changed later.

Look for changes in brick color, breaks in the foundation, roof lines that do not meet cleanly, and windows of different proportions on the same wall.

Does a revival style count as the real thing?

It is genuinely of its own moment, and reading it as such is more interesting. A revival house tells you what its builders admired and what they could actually afford to construct, which is a different and often better story than the original.

What if the house has been re-clad?

Then trust the massing and roof, and look at the reveals. New cladding rarely changes window positions or roof geometry, and the depth from the glass to the outside face of the wall usually gives away that a layer has been added.

Where does interior evidence fit?

It confirms or contradicts the exterior reading. Ceiling heights, stair position and door widths are hard to change, so they survive refits. The same reading is applied to specific rooms in New York homes interiors.

Which cities control what you can change?

Local review boards decide exterior work in all six cities covered here: Boston's Back Bay, Charleston's Old and Historic District, Santa Fe's historic districts, Chicago's designated landmarks and landmark districts, San Francisco's landmark districts and New Orleans' local historic districts. Ask before ordering materials.