Grant Mills Covered Bridge, Hardenbergh New York

Date added: April 18, 2024

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The Grant Mills Covered Bridge is a rare and substantially intact example of rural vernacular bridge design and construction in the Catskill region. Erected across Mill Brook in 1902 by local craftsmen using native materials, the 66-foot, single-span bridge incorporates the patented Town lattice truss design. Built as a highway bridge to serve the needs of local farmers and millers, the Grant Mills Covered Bridge is a late example of its truss type and method of construction, reflecting the persistence of timber construction techniques in rural New York into the early automobile age. By-passed and removed from service in 1964, the Grant Mills Covered Bridge was restored for pedestrian use in the early 1990s. As one of only ten Town lattice truss covered timber bridges surviving in New York State, the Grant Mills Bridge remains an important vernacular engineering and transportation landmark in the Catskill Mountain region.

Though the first permanent settlement of the town of Hardenbergh occurred around 1800, the area has remained remote and sparsely settled to the present. Forest products quickly became the chief output of this wooded, mountainous region region of the Catskills. Laced by numerous streams, this isolated area relied upon abundant local materials and available rural craft skills to provide needed road bridges, a regional trend that persisted into the first decades of the Twentieth century.

Edgar A. Marks, a local timber framer and sawyer, was awarded a contract to erect a bridge across Mill Brook, in the town of Hardenbergh, in 1902. The contractor hauled stone for the abutments and cut the timber which he sawed into planks (with assistance from his son, Orrin Marks). Assisted by several other local craftsmen, Marks began work in June; on December 8^th, 1902, the completed span was opened to traffic. The builder employed the time-tested Town lattice truss design, a sturdy and easily constructed configuration suited to the traffic loads the Grant Mills bridge would carry.

The Grant Mills Covered Bridge was restored over a two-year period (1990-1992) by descendants of Edgar A. Marks, the original builder. Currently maintained as a local historic landmark by the town of Hardenbergh, the structure remains one of a limited set of covered wood truss bridges remaining in New York State.

Although hundreds of covered wood truss bridges were built throughout New York, only 24 remain.

The history of covered timber bridge construction in New York State spans the period from the first decade of the nineteenth century to the era of the First World War. The earliest known extant covered bridge was built in 1825; the latest in 1912.

Throughout much of the nineteenth century, New York was predominantly rural; its settlement pattern generally consisted of widely separated communities whose economy was based upon subsistence agriculture and local water-powered industry. Few improved roads connected population centers. As the Empire State grew and its economy expanded, however, road and bridge improvements became essential for linking emerging centers of civic market activity.

The earliest permanent bridges in New York were constructed using readily available local materials and skills. Because the cost of constructing bridges generally was the responsibility of local governments, they turned to readily available materials and skills for this purpose. The abundant timber and stone resources found throughout much of New York State made these materials the logical choice for bridge construction during the period of significance. The relative ease of construction was another factor that mitigated in favor of wooden bridge construction. The timber framing skills of local millwrights and joiners were readily adaptable to the construction of timber bridges.

During the Colonial period, the first timber bridges incorporated the Kingpost or the Queenpost truss configuration. These simple, open structures with plank decks were widely erected across small streams, though their use was limited to clear spans less than fifty feet in length. Longer crossings were possible using multiple spans supported by mid-stream piers or timber cribbing. The open timber truss bridge remained an inexpensive and popular form for farm bridges and crossings on minor roads until the early twentieth century, when it was supplanted by the metal span. The open trusswork was sometimes sheathed with protective weather boards to preserve the life of the truss. Because of its horizontal top chord, it was possible to cover a Queenpost truss bridge with a protective roof. The Copeland Covered Bridge (1879), a farmer's bridge in rural Saratoga County, is an extant example of a covered Queenpost truss bridge remaining in New York.

From the early decades of the nineteenth century, the cost of building and maintaining timber bridges generally fell upon local governments or state-chartered bridge or turnpike companies, which were established as for-profit ventures. It soon became evident that protecting the bridge's structural system from the elements would reduce the burden of maintenance and replacement costs. This protection was most readily achieved by covering the timber truss bridge with a roof and board sheathing to enclose the frame structure.

During the Federal period, inventor Theodore Burr (1772-1822) designed a highly successful long-span bridge form that combined the structural advantages of a simple timber truss with a relieving arch. Burr patented his timber truss design in 1817. His first successful bridge was a four-span structure erected across the Hudson River at Waterford, New York in 1804. Built of hand-hewn pine structural members, the Waterford bridge was sheathed with pine plank siding and covered by a shingled roof. Burr's bridge stood for more than a century until it was destroyed by fire in 1909. The Burr Arch Truss is represented in New York by three extant historic covered bridges: Perrine's Bridge (1844), Ulster County, Salisbury Center Bridge (1875), Herkimer County, and the Hyde Hall Bridge (1825), Otsego County.

A successful truss design nearly contemporary with the Burr truss was the Town lattice truss, patented in 1820 by the versatile builder/architect Ithiel Town (1784-1844). Consisting of a horizontal top and bottom chord connected by a web of closely spaced, alternating diagonal timbers, the Town lattice truss included no vertical members; the required stiffness was achieved by connecting the intersecting diagonals with wood pins. Carried on piers placed at intervals, bridges incorporating the Town lattice truss could span considerable distances. Its inherent strength coupled with its ease of construction made the Town truss design a popular design for highway and early railroad bridges until the post-Civil War era. The covered bridges at Eagleville and Shushan, Washington County, are notable examples of the Town truss form.

During the 1830s, Colonel Stephen H. Long (1784-1864) of the U.S. Army Corps of Topographical Engineers perfected a rigid timber truss form that incorporated panels consisting of intersecting diagonals and counters. Long's initial patented design of 1830 for an "assisted truss" included a redundant Kingpost relieving truss above the center panel points (where the greatest flex would occur). With practical experience, Long refined his design to eliminate its "overbuilt" characteristics, receiving additional patents in 1836 and 1839. The Old Blenheim Bridge (1855), Schoharie County, (destroyed 2011) was a notable example of the Long truss design.

The final major timber truss design to achieve widespread popularity during the late nineteenth century was first patented in 1840 by William Howe (1803-1852). The Howe truss consisted of horizontal timber top and bottom chords and diagonal wood compression members combined with vertical tension members made of wrought iron. The ends of the iron tensions rods were threaded and secured to iron shoes at the panel points of the web. The inherent properties of wood and iron as construction materials were effectively used in Howe's truss; this hybrid truss became the most widely constructed, standard American timber bridge form of the nineteenth century. The Rexleigh (1874) and Buskirk (1857) Covered Bridges in Washington County and the Jay Covered Bridge (1857), Essex County, are Howe truss structures.

By the third quarter of the nineteenth century, the covered timber truss bridge was being supplanted by the manufactured metal truss bridge on the roads and rail lines of New York State. Stimulated by wartime growth and development, iron manufacturers turned to production of standardized metal bridge components in the post-Civil War era. The increased strength, ease of construction, and reduced cost associated with metal bridges won favor among local governments and railroad companies; by the 1880s, the heyday of wooden bridge-building had passed. Although several examples of covered timber truss spans remain from the early twentieth century in rural areas of New York, the advantages of iron bridges were clearly understood and widely applied well before 1900.

Bridge Description

The Grant Mills Covered Bridge is a wood plank framed, gable-roofed, single-span structure located in the town of Hardenburgh, Ulster County. Built in 1902, the span was constructed as a highway bridge on Mill Brook Road. Set amid the picturesque surroundings of the western Catskill Mountains, the bridge remains on its original site spanning Mill Brook. The structure is sited with its portal ends oriented east and west. The Grant Mills bridge was removed from service in 1964; at that time, Mill Brook Road was re-aligned a short distance south of the former right-of-way, thereby leaving the span isolated parallel to the modern road.

The general dimensions of the Grant Mills Covered Bridge are as follows:

Overall length: 69' 5"
Overall width: 16' 10"
Deck width: 13' 10"
Portal height: 11'

The timber bridge is a single span carried on roughly built abutments constructed of dry-laid fieldstone. The web of the superstructure incorporates the Town lattice truss. Heavy paired planks form the top and bottom chords, as well as the intersecting diagonals, which are joined by paired wood pins ("trunnels") at each point of intersection. Alternate timber floor beams extend beyond the sides of the bridge to form a series of four buttresses. The deck consists of planks laid on stringers running longitudinally between the portals. The entire bridge is covered with vertical board sheathing attached to horizontal nailers; the roof boards and buttresses are shielded by wood shingles.

An extensive program of restoration was carried out on the Grant Mills Covered Bridge from 1990 to 1992. The sagging trusses were jacked into alignment and failed truss members were repaired or replaced in kind; wood connecting pins were replaced at many panel points. Finally, the entire bridge was resheathed and a new roof was installed.