O’Kane Notebook IX: Down, Cape, DOWN!

Dave, Jim, Scott and Andrew, dismantling rafters, with Pete represented by the lull forks

Dave, Jim, Scott and Andrew, dismantling rafters, with Pete represented by the lull forks

Over the past month, an injection of new blood has invigorated the dismantling process. Not only have we three new Maine Preservation interns; Dave Ewing, Andrew Cushing and Noah Kerr, but Jim and Kendra, two clutch workers, to boot.  Brian Cox has been on site, managing the inventorying and dismantling of the windows (stay tuned for his upcoming window article) and Pete Dellea has been working his lull magic.  The eager crew dismantled the entire cape ell one full week ahead of schedule.  We can only hope that the rain stays away, and the house comes down as smoothly.

The Neat Stuff Update:

Dragon Spikes!

Dragon Spike

Dragon Spike

These spikes were used to pin the main house and ell frames together.  There were seven spikes in all, one in a rafter, one in the front gable tie, and five distributed between a corner post and a beefy stud.

Scott and Dave, Vanquishing the Dragon Spike

Scott and Dave, Vanquishing the Dragon Spike

Using levers, and some brute force, the rafter, post and stud were able to be pried, preserving master smithery.  The spike that did need cutting was in the gable tie beam, which needed to be lifted straight up, and could not be pried out.  It took six sawzall blades,  ground to nubs, to cut through that unlucky nail.

Half Doves!

Tie Beam to Plate Joinery

Tie Beam to Plate Joinery

For those non-timber-framers out there, a half dovetail is just like the first dovetail in a drawer, with one straight side, and one slanted one.  The geometry that a drawer-dovetail employs in order to resist the outward pull of the drawer front is the same geometry that is used in buildings; the half dovetail in a tie beam is resisting the outward thrust created by rafters.

Half dovetailed tie beam (with trunnel hole) and two adjacent joists

Half dovetailed tie beam (with trunnel hole) and two adjacent joists

In most English barns, only the tie beams have a half-dovetail joint on the end, and the attic joists half-lap over the plate.

Attic Joists, Upside Up and Upside Down, photo by Noah Kerr

Attic Joists, Upside Up and Upside Down, photo by Noah Kerr

In this building, every one of the attic joists had a half-dovetail joint, which helps to explain why these buildings stayed so square and straight for more than 200 years.

Teasel tenons!

Post hacked back, revealing mortise and pin that used to hold teasel tenon

Post hacked back, revealing mortise and pin that used to hold teasel tenon

In an English tie joint, the tie beam cogs over the plate with the aforementioned half dove.  The tie beam is also connected to the post directly below it, by means of a teasel tenon.  The confluence of so much joinery at the top of one post, i.e. tenon into plate AND tenon into tie beam, results in most posts flaring at the top, to as much as 11 1/2 inches in the case of the O’Kane house.

Two Mortises, One Plate, photo by Noah Kerr

Two Mortises, One Plate, photo by Noah Kerr

One tenon runs parallel with the eave of the house, and inserts into a mortise in the plate, (pictured directly above), and the other tenon runs perpendicular to the plate, parallel to the tie beam, and extends from the interior plane of the flared post.  This tenon inserts into a mortise on the underside of the tie beam. If that’s difficult to imagine, a few of the posts in the O’Kane ell were shaved back, revealing the innards of teasel tenon joinery (previous photo, above).

Interns!

Andrew and Kendra, preserving wrought nails

Andrew and Kendra, preserving wrought nails

We are fortunate to have been blessed with so many terrific Maine Preservation interns, as well as interns from North Bennett Street School and other interns with an unaffiliated, but unabashed interest in preservation.  They are always eager to learn and participate, as well as share their varied knowledge and experiences.  Thanks to interns past and present for your indelible contributions.

Please peruse the slideshow below for more photos of our process:

One thought on “O’Kane Notebook IX: Down, Cape, DOWN!

  1. Pingback: O’Kane Notebook XI: Demeritt Notebook? | Preservation Timber Framing

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