This summer the Preservation Trades Network partnered with the Timber Framers Guild to hold our second timber frame workshop the week of June 7-11 at beautiful Shelburne Farms, a membership-supported, nonprofit environmental education center and National Historic Landmark on the shores of Lake Champlain in Shelburne, Vermont. Thie workshop focused on historic restoration and repair techniques. The restoration and repair workshop was taught by Jan Lewandoski, a world renowned master timber framer. Additionally day one of the workshop (June 7th) featureed lectures and demonstrations by wood scientist Ron Anthony and structural engineer David C. Fischetti.
The program venue was the Victorian “Breeding Barn” at Shelburne Farm. It was built from 1889 to 1891 and at the time was said to be the largest open span timber structure in America. The architect was Robert Henderson Robertson. The structure has a footprint of 107’ x 418’ and includes some of the most elegant and truly ambitious trusses ever incorporated in an agricultural structure. Shelburne Farms was created as a model agricultural estate in 1886 by William Seward and Lila Vanderbilt Webb. In 1972, it became an educational nonprofit featuring nearly 400 acres of woodlands which are Green Certified by the Forest Stewardship Council, and a grass-based dairy operation with 125 purebred, registered Brown Swiss cows. Milk produced on the farm is transformed into award-winning farmhouse cheddar. The mission of Shelburne Farms is to cultivate a conservation ethic by practicing rural land uses that are environmentally, economically and culturally sustainable. <learn more>
The workshop covered:
The Breeding Barn at Shelburne Farms as a case-study for the investigation, analysis, and repair of historic timber buildings
Wood investigation techniques for historic buildings, including resistance drilling, digital radioscopy, and remote visual inspection
Historic and current techniques for modeling and analysis of timber frames
Cribbing and shoring for structural timber repair
Dismantling / selective demo
Deciding when to conserve and when to replace timber elements
Techniques such as free-tenoning and scarfed repairs
June 7th One-Day Intensive Workshop Program
Jan Lewandoski – Jacking, Cribbing and in-situ Repair of Timber Framed Structures
Learning Objectives:
Identify load paths (and alternative load paths) in a timber structure, and thus what weight may be accumulated at any given point.
Decide how to jack and shore a timber structure in a way that securely picks up this weight while leaving the artisan free to work on the loaded member.
Analyze choices in the design of structural timber repairs commensurate with the loads upon the member.
Knowledge or skills participants will gain from this program:
Increased ability to structurally analyze a timber building.
Techniques of jacking and shoring.
Design and layout in the field of repair joinery.
Discussion of the aesthetics of timber repair
David C. Fischetti – Evaluation and Repair of Timber Structures
The purpose of this session is to describe the structural engineer’s approach to the evaluation and repair of timber structures. At the barn, the composite roof trusses had to be measured and analyzed to determine how they are performing. Load testing of the structure and non-destructive testing of the timber and wrought iron materials will be discussed as well as laboratory testing of potential repair techniques made in full size specimens.
Learning Objectives:
To develop an understanding of the analysis of timber and composite structures during the last half of the 19th century and through the first half of the 20th century, how they vary from today’s methods, and what ramifications might result.
Learn about the construction of composite structures and how performance of the Shelburne Barn during construction may have affected design modifications.
The attendee will learn how observation, analysis, and testing can form the basis for a rational approach to the repair of timber structures.
Knowledge or skills participants will gain from this program:
Participants will gain an understanding of the array of design, testing, and repair options available to the design team in establishing repair solutions that will ensure continued serviceability.
Learn repair techniques that will result in the minimal loss of historic fabric in keeping with the best of preservation philosophies.
Participants will gain knowledge in the approach to a preservation project consisting of large timber structural components which must be evaluated based on a determination of allowable design values and the effects of deterioration.
Ron Anthony – Investigating Hidden Conditions in Timber Structures
Session Description: Determining a repair strategy for timber structures should be based on a sound understanding of architectural, engineering, material, and craft issues. It also requires knowledge of the type and extent of deterioration, which is often not visible. Resistance drilling is one technique that provides information about the hidden conditions of wood. The term “resistance drilling” has been used to describe any drilling technique intended to measure the ease of drill penetration into wood. In this context resistance drilling is a quasi-nondestructive assessment method where a specialized drill pushes a small diameter needle through wood and displays a graph of the relative wood density. Demonstration of this method will show that it is reliable for quantifying the extent of internal voids due to decay or wood-boring insect activity. Using the inspection results to specify material requirements will improve communication between project team members and increase the likelihood of a successful repair.
Learning objectives:
Using wood issues as a backdrop, develop an understanding of the benefits of using an interdisciplinary team approach for creative problem solving in preservation projects.
Learn about behavior, deterioration, and assessment of wood as a building material.
Learn key components for writing specifications for wood repairs.
Knowledge or skills participants will gain from this program:
Learn about the causes of wood deterioration.
Gain an understanding of considerations when conducting a wood condition assessment.
Learn about nondestructive testing techniques for inspecting wood.
Gain an understanding of key factors to consider when writing a specification for wood repairs.
Instructors:
Jan Lewandoski is a timber framer with more than 30 years experience in the repair of the frames and finish work of barns, houses, wooden bridges, churches, and public buildings constructed during the 17th to the 20th centuries and across several cultural traditions. Recent projects include the construction of four medieval type raised bottom chord trusses for a new church (Lyndonville, VT), restoration of the roof trusses and floor systems of a 90-foot long stone barn (Isle laMotte, VT), restoration of the tower and octagonal cupola of the Grand Isle County Court House (Grand Isle, VT), and the reconstruction of a 20-room restoration 18th century house moved from China to the Essex-Peabody Museum (Salem, MA). Jan’s company, Restoration and Traditional Building, is currently working on timber frame repair of the Breeding Barn.
Doug Porter (School of Engineering, University of Vermont / Conservation Associates LLC) is an architectural conservator who directs grant-funded research in the conservation of historic sites in cooperation with academic, federal and non-profit partners. Recent projects include investigation of structural and decoratively painted wood at Mission San Miguel, organization of a Colloquium on the Development of Curricula for a Program in Heritage Preservation Engineering, stabilization of the Las Flores Adobe NHL, conservation of architectural redwood at Scotty’s Castle in Death Valley National Park, and structural evaluation and stabilization of the aerial tramway in the Keane Wonder Mine. Since 2005, he has been supervising the investigation and structural stabilization of the Breeding Barn at Shelburne Farms.
Ronald Anthony (wood scientist for Anthony & Associates, Inc.) has applied innovative inspection technologies to the assessment of wood in historic structures since 1985. His projects in the U.S.A. include the Shenandoah-Dives Mill and Tram Terminal (which was also a HAER/ HALS Workshop), the Hanging Flume (on the 2006 World Monuments Fund Watch List), Benjamin Latrobe’s Basilica of the Assumption in Baltimore, the Breeding Barn at Shelburne Farms, and Gustav Stickley’s Craftsman Farms in New Jersey. He has authored approximately 85 publications; participated in conferences and seminars; and consulted throughout North America, Europe, Asia, Africa, Australia and the South Pacific. Mr. Anthony is the 2002 recipient of the James Marston Fitch Foundation Grant for his approach to evaluating wood in historic buildings.
David C, Fischetti, P.E. (DCF Engineering, Inc.) is a structural engineer specializing in timber construction, and the author of Structural Investigation of Historic Buildings: A Case Study Guide to Preservation Technology for Buildings, Bridges, Towers, and Mills (John Wiley & Sons). David has 39 years of structural design experience, is registered in 19 states, and is the engineer of record for the investigation and stabilization of the Breeding Barn. Recent projects include James Madison’s Montpelier in Orange, Virginia, and Lake Mattamuskeet Lodge Repair and Renovation in Hyde County, NC. In 2003 Mr. Fischetti was honored as a Kentucky Colonel for his contribution to the restoration of covered bridges in Kentucky.
