Crafting Douglas Fir Key Beams for CNC Software Barn Addition in Tolland, CT

Designing and engineering key beams for use in an 1800s post and beam barn addition is both a science and an art. Learn more about the unique key beams we’re crafting in order to clear span 22' without using glulam beams.

Closeup of Wedges in Key Beam
Closeup of Wedges in Key Beam

The CNC barn is perhaps the most iconic and well known barn in Tolland, CT. We are currently adding a 1,728 sq ft addition to the existing 1800s timber frame barn. The plans for the barn addition project call for two 22' clear span floor girders to span the second floor loft. We used these beams as an opportunity to do something more unique that speaks to an bygone era of beauty and engineering virtuosity. We designed two Douglas Fir “key beams.” The way a key beam works is two solid sawn Douglas Fir beams connected together with maple wedges that remain exposed and add detail to the beam. We used maple in this case because it’s even harder than the oak wedges & pegs traditionally used in our joinery. Our engineering expertise allows us to perfectly angle the maple wedges to join the adjacent timbers in order to transfer shear and limit interlayer slip. It will be a special feature of the barn addition that will be in keeping with the historic period of the original structure.

Here’s what the finished post and beam barn addition will look like.

3D Rendering of CNC Software Post & Beam Barn Addition in Tolland, CT

3D Rendering of CNC Software Post & Beam Barn Addition in Tolland, CT

Posted to Blog: Wednesday, June 22, 2016