Dutch Barn Preservation Society

Dedicated to the Study and Preservation
of New World Dutch Barns

NEWSLETTER, Spring 1990, Volume 3, Issue 1, part two.

The barn owner contemplating repair or maintenance of any barn needs to know as much as possible about the history of the barn in question. The barn's original use, the additions and changes that have been made, and the way the setting has been altered over the years are basic pieces of the puzzle. Before beginning work, the owner should try to unravel the construction secrets of the barn. Last comes assembling information about possible preservation/repair choices as well as about methods for each proposed repair. The following article and Everett Rau's "If a Barn Could Talk" deal with this process.


Suggested Guidelines for Timber Frame Repairs

Text by Dave Carlon
Illustrations by Jack A. Sobon
Over time, barns are subjected to weather, traffic, accident and hard use, and therefore, require periodic maintenance and repair. Where maintenance is neglected, structural repairs to the timber frame itself may become necessary. Whether a barn needs only minor repair or shows signs of serious deterioration, non-barn related debris and stored extraneous materials should be cleaned out on the interior, and moisture-producing trees, shrubs and weeds should be cleared away on the outside. Then, an initial survey identifying two categories of information needs to be compiled. One category should list the frame component or part thereof needing repair (sill end, post bottom, rafter foot, etc.); the other category should name the cause of the problem necessitating the repairs to each part. From this information, a two-phased plan is made to 1) rectify the causes for the problem, and 2) make the actual repairs. Rectifying the cause of the problem may be enough to prevent further deterioration and actual repairs may not be necessary. For example, a leaking roof will cause water staining, which with frequent enough wettings can lead to fungal growth and rot. This sets up favorable conditions for insect damage, and eventual structural failure will be a result. Repairs to the roof at the initial stages of this scenario will preclude the later stages. Unfortunately, often detection occurs at a much later stage and more substantial repairs are required.

There is a story to be told by each component member of a barn - the variety of tree species used in a barn, its place in the frame (i.e. white oak sills for rot resistance), its form (white pine can be straight enough for 60-foot single piece plates), its grain character and wood properties. Each choice made by the builder bespeaks the forest of the period or the wood supply available at the time the barn was built, as well as revealing something about local technology at the time. Each hewn surface has recorded on it the footprint of the tools used and the method used to fashion that component. One part may contain inscribed markings and numberings of consequence to the whole building, which is indeed greater than the sum of its parts. There are also stories in the frame which we have not yet learned to read. In as much as these buildings are a link with our past and with endangered traditions, repairs should be planned and carried out with the underlying philosophy of preserving as much of the original fabric of the structure as possible.

The repair process involves deciding on a temporary or permanent repair, designing the repair, choosing the compatible or appropriate repair material(s), and carrying out the repair. While temporary repairs are generally quick and may reflect an emergency situation, permanent repairs are more thoroughly designed for an effective and eye-pleasing solution, conforming to the original parts in form and function. Choosing a wood with natural decay resistance may be desirable. USDA's Wood Handbook: Wood as an Engineering Material, 1974, lists among others the following species as resistant or very resistant to heartwood decay: black cherry, black locust, white oak, chestnut, and black walnut. More important is that the repair wood be as strong or stronger than the original in load-bearing parameters. Current design values such as those published by the Northeastern Lumber Manufacturing Association should be consulted. Repair illustrations follow.

Temporary repair for decayed or broken rafters, beams, and joists.

The authors are timber-frame specialists with a particular interest in barns.


Dutch Barn Basics - Cues to Understanding Your Barn

The following information on foundations, roofs and siding of barns is extracted from "Dutch Barn Miscellany," an informal publication authored by Dutch Barn Preservation Society Trustee and founding member Vincent Schaefer.

Foundations

The foundation of the Dutch Barn characteristically consisted of piles of flat or semi flat stones arranged to support the sills of the barn; the stones were located at strategic spots around the periphery and under the posts supporting the anchor beams. Thus, the floor of the barn was held several feet above the ground so as to permit adequate air circulation beneath the barn floor. In some instances, if the barn must be located on a moderate slope, a solid dry wall was built so that the sills were level. This never interfered with good ventilation. The sills were large, frequently 12" by 12" in cross section. With larger barns, there was a center or median sill (see illustration) which permitted utilization of floor planks slightly less than half the width of the threshing floor. The stone piers used to support the sills were generally of native sandstone or limestone which splits naturally into convenient thicknesses. When the ground beneath the barns was dry, problems with frost heaving were of no consequence.

Floors

The floors of many Dutch barns are original. They may consist of oak planks 3 to 4 inches thick, 12 to 15 inches wide, and 12 to 16 or more feet long. These rest on top of the sills and in some instances are fitted into a median strip. (See the Dutch Barn Preservation Newsletter, Spring, 1989.) In some cases, the heavy plank floor is made of unevenly split planking-with some of the planks as much as six inches thick. These are recessed on the sills, so as to be even with adjacent, thinner planks. Frequently the planks are fastened to the sills with wooden pins (trunnels or tree nails) similar to those used to secure other framing members.

Roofs

Roof coverings may range from original plank roofs or shingles to modern coverings. In a few instances, slate roofs (not original) have been installed. Metal sheeting has been used on many barns. When properly installed, such a roof is probably less expensive than any other and has a long lifetime.

Siding

The sheathing of the side walls of the Dutch barns of the Hudson, Mohawk and Schoharie valleys consisted of pine planks. The planks of classic barns are generally 1" thick and 13" deep, and may be some 13 to 15 feet in length. They were horizontally applied and lapped by an inch or more and were nailed directly to the posts (above, not through, the board below) with large hand-wrought rosehead spikes. (See illustration.) In most instances the boards were not painted but were allowed to "weather." In the siding on the upper part of the gable ends were three to five martin holes which served a dual purpose; they ventilated the upper part of the barn as well as providing ready access to the barn's interior for martins, other swallows, and any other birds who chose to enter and feed on the insects brought into the barn with the harvest. A number of barns are still sheathed with original planking cut more than two centuries ago. Without paint protection, this asserts the durability of virgin pine lumber so long as it is kept dry. When wet by driving rain, the wood would quickly dry once the storm had passed.

 

The Dutch Barn Preservation Society

c/o The Mabee Farm Historic Site
1080 Main St. (Rt. 5S)
Rotterdam Junction, NY 12150

Site Phone: (518) 887-5073

 

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