While building architectural styles such as "Victorian" continue to be built into the present, the combination of a recognizable architectural style with an inspection of the building materials which have been used provide considerable information about the age of a home as well as its history of changes and additions.

Here is a photograph of an unlined single wythe brick chimney on an 1856 home in New York State.

The location, size, shape, building materials, and use of chimneys on buildings offer good details aiding in estimating the age of a building.

These details can also indicate where additional safety inspections or perhaps repairs or updating are needed for safe use of a chimney, fireplace, building heating system, or woodstove.

Chimney materials vary among none (a hole in a roof), brick, stone, masonry block, metal flues, insulated metal chimney flues, and wood-framed metal flues on buildings.

Here is a photograph of an obsolete 30-Amp electrical meter and fuse panel, ca 1935.

While varying somewhat by area of the country in the U.S., Latin America, Europe, and other areas, there are recognizable generations of electrical wiring (knob and tube, greenfield, armored cable or "BX" wiring, plastic or "NMC" wiring), wiring materials (copper, tinned copper, aluminum, copper-plated aluminum), and also, easily recognized generations of electrical meters and electrical service panels.

Here we illustrate various of these materials and products and we provide information about their safety or about the need to inspect or perhaps replace or upgrade certain problem equipment such as Federal Pacific Stab-Lok electric panels or solid-conductor aluminum wiring.

Here is a photograph of an early (pre-vinyl) continuous floor covering, ca 1900, in an 1840 historic Vermont house.

Note the fabric backing of the flooring material. Here we discuss various common flooring materials (rough wood, finished wood, parquet, carpeting, linocrusta, sheet vinyl, and other items as they assist in determining the age of a house or other building.

Photograph of a buckling, damaged stone foundation on an 1864 structure in Rhinebeck, NY.

In evaluating the probable age of a home when inspecting its foundation, we consider the foundation materials and style of workmanship.

A building's foundation materials and style of construction, stone, wood, brick, masonry block (at least two different generations), and poured concrete (various generations and methods including hand-built and by machine and pumper truck) can give considerable information about the foundation age.

On occasion we'll find a very old structure which has been moved and re-set on a new concrete or concrete block foundation, adding more historical information to the home.

Here is a photograph of post and beam framing with joint number markings.

The observation of framing materials, framing markings, and framing styles provides considerable information about the probable age of a house.

We discuss framing materials and styles here as an aid to house age determination.

Also see our article on "Saw Cuts and Tool Marks" (links at page left).

Above we show a photograph of an "octopus heating furnace", originally coal fired, usually by now (if still in use) converted to natural gas fuel.

These octopus furnaces, also called "gravity heating systems" provided heat by natural convection, hot air rising into the building from the top of the furnace where it was delivered to the building first floor through a wood or iron grate, or perhaps delivered through metal ducts.

The original installation usually supplied heat to a home through a central grate in the first floor of the building from where warm air might rise to upper floors. Later versions or modified original systems added ducts to individual rooms, sometimes still only on the first floor of the building. These furnaces are the ancestor of modern forced hot air heating systems.

Here we discuss types of heating systems (octopus furnaces, forced air heating systems, steam boilers, forced hot water boilers, high efficiency systems) and fuel types (coal, oil, gas) as an aid in determining the age of a home or other building. Where there are special safety or maintenance concerns for certain systems we cite those as well.

Photo of brick wall lining used as insulation and as a wind or draft block. Brick nogging can determine the probable age for the home.

Houses built between 1810 and 1900, or perhaps earlier may have brick-lined walls. I have found brick nogging in the walls of a 1790 Poughkeepsie NY home.

Bricks lining the walls of a home is an indicator of when it was built. See Brick Lined Walls for a detailed, illustrated article about the use, detection, and inspection of brick lined walls in older homes were we describe and explain the reasons for and concerns with brick wall lining or "insulation" sometimes called nogging.

Here we discuss various types of insulation materials (none, air gaps, brick, cellulose, corn or corn husks, hay bales (including hay bale or straw construction), straw, newspaper, rock wool insulation or mineral wool, fiberglass insulation, asbestos insulation and fire barriers, UFFI and other foam insulation materials, and the use of radiant barriers) and their common eras of usage as an aid to determining the age and history of a building. Health and environmental concerns and insulation effectiveness are also addressed.

A close observation of the type of fasteners used in a building is one of the most popular means of estimating its age. Hand wrought nails, machine cut nails, modern round "wire" nails and other details offer considerable information about the time of original construction of a building as well as of the time of modifications to the structure.
Tremont Nail Company continues to manufacture reproduction nails which in appearance are quite like those made by hand more than 100 years ago.

Tremont supplies restoration contractors and others working on historic buildings and for historians, Tremont offers a reference set of old fasteners. (See Tremont at "More Reading" below.)

Shown is Tremont's standard Clout Nail: Similar in design to Shingle Nails, but made from lighter gauge steel. this nail was (and is) used for the application of thin siding and paneling. It was and is also used for furniture repair, cabinet work, batten doors and counter tops. (Photo courtesy Tremont Nail Company).

Photograph of hand-split wood lath and plaster wall, from the wall-cavity side. Ca 1800.

There are several generations of plaster and lath, plaster board, and drywall which have been used in buildings.

We name and illustrate these and discuss their periods of use below as an aid in finding out how old a building is and tracing its history.

Photograph of an active gaslight found in a 1900 home in New York.

Often old gas lines have been disconnected entirely and sometimes they have been re-used to route electrical wiring to new light fixtures or to gaslight fixtures which have been converted to electric. Don't assume that an old gas fixture or valve on a wall or found in a fireplace are inactive.

We turned-on and lit this fixture which was a surprise to everyone.

Plumbing fixtures and piping materials offer considerable age in dating a building, including easy clues such as the presence of a date of manufacture stamped into many toilet tanks to the periods of use of types of water supply piping (lead, galvanized steel, black iron pipe, copper, plastic piping) and building drain piping (lead, cast iron, copper, plastic, clay).

Often on older buildings multiple types of piping will be present as repairs and changes have been made in the building plumbing system.

Wood shingle roofing has been in use for hundreds of years in the U.S. and Europe.

But an inspection of interior and exterior roofing details can indicate the probable age of a wood roof (which can last up to 40 years) as well as the roofing history of the building, the number and types of roofing layers, and related house-age-determination details.

The wood shingle roof shown in the photo below is on a building in Key West, Florida, adjacent to the Hemingway house, viewed from the Key West tower. Notice the absence of lichens on the wood shingles in the roof area below the metal-flashed rooftop tower?

We discuss here various roofing materials (Wood, slate, asphalt shingles (in several generations), clay tile, metal roofing (several styles and generations), and how they assist in finding the age of a house below.

The saw cuts visible by flashlight on this sawn beam form an irregular "vee" shape, a clear indicator that this beam was cut by hand using a two-person pit-saw.

This beam was cut before mechanical saws were available, but after hand-hewn beams or raw logs were in common use. This places the age of this structure perhaps in the mid 1700's.

We can contrast these saw marks with the mechanical pit saw which followed, then with circular saw marks, and later with planed dimensioned modern lumber of two generations. We include illustrations of these markings and surfaces below.

Adze marks on hand-hewn beams, generations of types of saws used in cutting beams, and similar details are readily available on many buildings and offer both clues to building age and wonderful aesthetic detail.

An understanding of how hand-hewn beams were cut, for example, can permit the careful observer to not only recognize the type and age of building framing, but even to understand just where the worker was standing when a blow from a tool was delivered to a building framing member.

This detail offers a very personal connection to the age of a building and to its past construction.

A photograph of stencil numbers on wood framing shown here confirms that this building was a Sears Kit House whose model and probable age we can determine.

Other kit homes were sold by Montgomery Ward and by a few other manufacturers including copies of some of the popular Sears and Roebuck houses that continued to be sold after Sears had discontinued their production.

Here we discuss types of kit homes including kit houses and log home kits which, in the latter instance continue to be improved and sold.

For more details, photographs, books, and references on how to identify Sears Kit Homes see Sears Houses: How to identify Sears catalog kit houses photos and tips for identifying these interesting homes.

Asphalt siding such as that shown in the photo of an extension on the rear of the Coolidge Hotel in White River Junction, Vermont, was the "aluminum siding" of the 1930's and 1940's in the United States.

That is, it was a popular "no maintenance" siding material sold often as a cover-up product for older siding in poor condition. (Aluminum siding and then vinyl siding were sold both for that purpose and also as exterior wall cladding for new construction as well).

Asphalt siding material was made in two common versions, one much like asphalt roof shingles and the other (as in this photo) was comprised of an asphalt coating laminated to hardboard siding material.

Commonly made to look like brick, it also appears in faux-stone versions (not to be mistaken for "perma stone" which has been sold since the 1960's as an exterior wall covering. It would be rare to find asphalt-based exterior siding material as original wall cladding on a building; usually it was applied over wood clapboards which in turn were badly in need of paint or repair.

Details of how this material deteriorates and examples of its variations are discussed below along with other exterior siding materials and their common dates of use.

Here is a photograph of an 1840 window latch on a historic landmark property, the Justin Smith Morrill Homestead in Strafford, Vermont.

Here we discuss windows and doors as clues to building age, including window style, size, placement, construction, and hardware, as well as door style and hardware.