Repair

Note:

This paper was prepared as a statement of personal opinion. It is based on hands-on experience working on perhaps two hundred antique barns and timberframed houses since 1974 in and around Tompkins County, New York. This paper has been reviewed by the Technical committee of the NYSBC, and by members of the Traditional Timberframers Research and Advisory Group (Timberframers Guild of North America) and several suggested revisions have been made. However, all reviewers do not agree with all the opinions stated here, so it remains the personal opinion of the author. Many recommendations contained here are the guidelines of the US Secretary of the Interior or the NY State Office of Parks, Recreation and Historic Preservation.

General:

Please see the standards for preservation as outlined by the US Secretary of the Interior. It is important to preserve not only the original fabric of old barns but also the carpentry skills and technologies as well as the layout and framing system used to create a building from trees in the woodlot. My idea of a proper barn repair is one that, except for the glow of green wood, and perhaps a scarf joint in the frame, cannot be recognized as a repair.

Layout System:

A layout system is the method that a builder uses to mark timbers for cutting so that the intent of the building's design can be realized when it is erected.

During the period most of our historic timberframed barns were built there were three layout systems used: scribe rule, square rule, and mill rule. Repairs should be made in whatever layout system was used by the original builder, and that joinery should match the original. Using traditional layout and joinery makes sense economically as well as historically.

The barns with the magnificent heavy timbered frames were built using the scribe rule, square rule, and mill rule layout systems. These layout systems are similar. The very oldest barns in NY were built to the scribe rule. Scribe rule barns are most readily
identified by marriage marks on the layout faces of mated timbers. Marriage marks are usually scratched-in roman numerals with other identifying marks. The scribe rule died out in use pretty much before around 1820 and was replaced by the square rule layout system, which was very much in use by 1810. The mill rule is an adaptation of the square rule made possible and recognizable by the use of accurately sawn timbers

Understand the square rule layout system and all the mysteries of timberframed barns disappear. Illiterate carpenters with only a pencil or scratch awl, a framing square and the ability to remember 10 principle dimensions of a barn could lay out all the cutting of a frame without plans. Education of modern carpenters is important in acquainting them with old time layout systems. Why ruin an old frame because of modern ignorance?
Barns timber-framed in the square rule should be repaired with replacement members cut in the square rule. Barns timber-framed in the scribe rule or mill rule should be repaired with replacement members cut in the scribe rule.

For explanation of the square rule and scribe rule, please consult the Timberframers Guild of North America. The guild offers publications that do an excellent job of explaining and teaching the square rule and scribe rule, such as the Look for postings by Rudy Christian and Jack Sobon.

Starting around the turn of the twentieth century, barns were beginning to be built from sawn 2" sticks of various widths. (commonly called two by's). Some of these barn frames were built by nailing together two by's to resemble heavy solid timber frames (built up frames). Later, house framing (balloon framing) was adapted for building barns. Balloon framing is still widely practiced and understood by frame carpenters today. Repairing a balloon frame is usually a case of removing a rotten or broken frame member and replacing it with a stick sawn to the same size as the original and nailed into place. Repairing a built up frame is similar.

Timber:

For the most part, the earlier the barn, the more the likelihood that it was built from trees growing close to the site. The later the barn, the more likely the materials were brought in from afar. Hemlock timbers from the Southern Tier of New York were transported by rail all over the state starting with the spread of rail service. In the1890's yellow pine siding was shipped up from the south for the cost of rail transport.

If the barn is early it may contain timbers of species that are not replaceable because the species is extinct (American chestnut). Or species may have been used such as walnut,
cherry, beech, tulip poplar, maple, or red oak, which have become very expensive (cherry and walnut timbers today cost almost 10 times as much as hemlock) or are inappropriate for use in the location of the original timber (most of the above species as sills, beech as floor joists etc).

If the species cannot be matched because of expense or extinction, replacement timbers may be cut from an alternate species that could or would have also been used at the time of original construction. There are small and large lumber mills all over New York. These mills buy local trees to cut and most will custom saw boards or timbers to your
specifications. Lengths, however, are usually limited to 24 feet. In general hardwood timbers should be replaced with hardwood, softwood with softwood. Where a timber to be repaired or replaced was originally hewn, I think, in the interest of conservation, (hewing creates a lot of waste) replacement timbers may be sawn but should be sawn to the original size of the timber to be replaced.

There is no place for modern dimension lumber and certainly no place for pressure-treated lumber in making repairs on historic barns. These buildings were mostly built with green lumber; they have stood the test of at least a century's time and with adequate maintenance are still standing.

Barns in the best condition had the best maintenance. I don't think that chemical treatment for rot prevention can keep a barn standing where maintenance is poor. And replacing locally sawn or hewn timbers with dimension lumber built up to match what
could be a locally sawn timber matched to the original barn frame in size and joinery makes no sense economically or in a preservation sense.

There are those that would argue that using dimension lumber makes the job more affordable but I strongly disagree and am willing to back up this statement with facts and demonstration. Dimension lumber sawn in 1 1/2 " thickness cost twice as much as an equal cross section of rough cut timbers and labor time to install such built up timbers is greater because the carpenter is working and installing many more members. As far as material cost goes, suppose you are replacing a twenty foot section of 8"x10" sill. If you have an 8"x10"x20' milled locally at say $.60 per board foot, the cost of the timber would be $80. If you buy 7 - 2x8x20 at a current price of $22 each to build it up, the cost would be $144 and you end up dealing with a timber with a cross section of
7 1/2 "x10

© 2010 New York State Barn Coalition