Design & Construction

San Juan County barns range from the period of earliest EuroAmerican settlement in the islands—1860s—to the ‘cut-off’ date of 1959.  The barns themselves are found in a variety of sizes, shapes, and structural systems.  Roof shapes are the most commonly defining barn feature.  Early designs were simple gable roofs, consisting of two equally pitched slopes.  Farmers added shed roofs to one of more sides, giving some barns their ‘spread-out’ appearance.  The need for more space in the hay loft led to the development of gambrel (two slopes per side), gothic (pointed arch), and bow (continuously curved) roof shapes.

Early barns were constructed with timber frames: hewn posts and beams that were connected with pegged, mortise-and-tenon joints. Later, builders erected simple poles with beams attached with nails or spikes.  With the advent of milled lumber and standardized plans, frame walls supported trusses, which were in turn built up with sections of small, dimensional “2xs” to form the distinctive gambrel and bow roofs that we associate with classic dairy barns.  The most common siding of barns consists of thin (¾-1”), wide (9-12”) boards nailed vertically to the frame.  Although the gaps between the boards were often left to allow for ventilation, battens—narrow strips of wood—were sometimes added.  Some barns have milled horizontal siding such as clapboard (lapped boards) or shiplap (boards with rabbeted joints).  Early barns were roofed with cedar shakes or shingles; lately, metal is most commonly used.

For detailed information on how barns in the San Juan Islands were located and sited, designed, and constructed, go to:

Confused about the terms in all this barn talk?  Try our Glossary of Barn Terms.

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