Caring for an old barn

Understand the barn first

The National Park Service's preservation brief on historic barns starts not with tools but with study. Before restoring a barn or adapting it to a new use, it says, an owner should find out when it was built, who built it and why, how it changed over the years, and what condition it is in. Old photographs, family records, deeds and insurance papers can help, as can neighbours, former owners, local libraries and historical societies.

The point of that study is to recognise what gives the barn its character, so that work does not destroy it by accident. The brief lists the elements to look at: the setting of fields, fences, silos and outbuildings; the form, especially the roof; the materials; the few, large openings; the open interior spaces; the exposed structural frame; and decorative features such as paint schemes, cupolas, weathervanes and painted signs.

Keep water out

The brief names water as the biggest single cause of decay in building materials, so repairing roof leaks comes first. Its routine maintenance list follows from that:

• Inspect regularly for damage and decay, and fix problems as soon as possible.
• Replace broken glass in windows and cupolas, and broken ventilation louvers.
• Clean gutters and downspouts once or twice a year, and make sure the ground drains away from the foundation.
• Remove soil and manure built up against the foundation; it holds water and snow against wood and invites rot and insects.
• Check for termites, carpenter ants and powder post beetles.
• Clear vegetation growing on the barn, and trees or shrubs whose roots threaten the foundation.
• Repair loose clapboards, check foundations for cracks and settling, lubricate door hardware yearly, and keep lightning rods working.

The USDA Forest Service's Wood Handbook explains why dryness matters so much for a wooden barn. Serious decay happens only when wood's moisture content rises above the fiber saturation point, on average 30 percent, which takes liquid water from rain, condensation or contact with wet ground; humid air alone is not enough. Air-dried wood is usually at or below 20 percent moisture, a reasonable margin of safety. Wood kept air dry will not decay, and decay already present will not progress.

Fire and hay

Barns hold a great deal of fuel. The National Park Service brief notes that curing green hay can generate enough heat to start a fire, which is why barns need good ventilation. Penn State Extension's fire safety guidance for horse stables, which applies to any barn that stores hay, adds detail: most hay fires occur within 6 weeks of baling and are usually caused by too much moisture in the bale, and hay is ideally baled at 15 to 18 percent moisture. It warns that there is no such thing as a fireproof building, that most barn fires happen in winter when feed and bedding are stored and electrical use is high, and that faulty electrical systems are high on the list of causes. The brief notes that wiring in an old barn may need a major overhaul.

Structural warning signs

The brief lists signs of structural trouble that may need a structural engineer to evaluate:

• major cracks in masonry walls;
• walls that bow, lean or are out of line, and windows and doors that sag;
• siding pulling away from the frame, or trusses pulling away from their seats;
• sagging joists and rafters, and dips in the roof between rafters.

Typical remedies, it says, include resetting or partly rebuilding masonry foundations, repairing or replacing sills and plates, straightening walls and tying them back into the frame, and bracing or splicing individual members.

Repair before replacing

The core principle in both the brief and the Secretary of the Interior's Standards for Rehabilitation is the same: repair deteriorated features rather than replace them, and where replacement is unavoidable, match the old in design, colour, texture and other visual qualities and, where possible, material. Missing features should be replaced on the evidence of what was there, not by guesswork.

• Roofs. Replacing one roofing material with another can change a barn's appearance drastically. The brief's first priority is to replace in kind. Dormers, cupolas and ventilators provide needed ventilation and should be repaired, not removed.
• Siding and paint. Repair and repaint historic siding rather than covering it. The brief warns that artificial siding can hide craft details and conceal continuing decay underneath. Unpainted brick or stone barns should never be painted.
• Masonry. Repoint with mortar compatible with the old in appearance and make-up; mortar high in portland cement can damage historic brick and stone. Clean only when needed, by the gentlest means; sandblasting and high-pressure power washing damage historic material.

The brief illustrates these principles with a bank barn at Antietam National Battlefield, owned by the National Park Service. The ground was regraded for drainage, a deteriorated metal roof was removed, the rotten wall plate and rafters it had hidden were replaced, new gutters, downspouts and drain pipes were fitted to carry water away from the foundation, and damaged structural members were strengthened with new sections. The barn remains a working farm building.

New uses

Some barns still do the job they were built for. Others need updating for modern farming, and some can only survive in a new use. The brief gives seven approaches for rehabilitation: preserve the setting, including the barn's relationship with its silo; repair siding rather than covering it; repair windows and avoid adding many new ones; avoid changing the size of door openings; add a new addition only if it is essential, and make it compatible but distinguishable; keep the interior spaces; and keep as much of the historic structural system as possible. The Standards for Rehabilitation, codified in 36 CFR Part 67, say the same in general terms: a new use should need minimal change, and new work should be differentiated from the old and removable without harming it.

The brief is cautious about housing. Conversions usually add many windows, heavy insulation, new floors and residential landscaping, and rarely preserve a barn's character; it notes that some "conversions" keep only the frame inside a new building, so that the timbers survive while the barn itself does not. Successful conversions start with a modest barn whose volume can be used almost as it is. Some types are hard to reuse at all: the Maryland Historical Trust notes that the tiers of poles in a tobacco barn fill much of its interior.

Recognition and records

The National Register of Historic Places is the official list of the nation's historic places worthy of preservation, authorized by the National Historic Preservation Act of 1966 and holding more than 100,000 listed properties. According to the National Park Service, a nomination usually starts with the State Historic Preservation Office; a property is judged on its age (generally at least 50 years), significance and integrity. Under federal law, listing places no restrictions on what a non-federal owner does with the property unless a federally assisted project is involved, and a property is not listed if its owner objects. Listing can open the way to some preservation incentives; the brief adds that State Historic Preservation Offices can help with rehabilitation plans and with finding experienced professionals.

The Historic American Buildings Survey, begun in 1933, is the nation's first federal preservation program. With its companion programs for engineering works and landscapes, it creates measured drawings, large-format photographs and historical reports, archived at the Library of Congress and available to the public without restriction. Its collection deliberately includes utilitarian and vernacular buildings, barns among them, and several photographs in the barn brief come from it.

Money is limited. The North Carolina State Historic Preservation Office, for example, says that with extremely rare exceptions there are no grants for private restorations of tobacco barns, though its staff offer consultations when time allows. Ask your own state office what applies where you are.

Example: a first season

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