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Dating the New Room’s Summer Beam

Summer beam inspection

The Mansion Revitalization Project continues to uncover fascinating layers of history. One area of focus has been addressing key structural elements, such as the one in-situ summer beam in George Washington's New Room. The summer beam, a critical framing component, offers insight into the evolving history of the Mansion while also presenting a unique preservation challenge.

What exactly is a summer beam?

A summer beam is a load-bearing beam in a timber-framed building. It’s one of the principal framing members that support the floor joists. With a room as long as the New Room, summer beams are necessary to break the span of the floor joists and support the load. In the 18th century, they would have been large wooden timbers.

Summer beam inspection
The New Room’s one surviving summer beam, the large wooden beam running from left to right, is a principal framing member that supports the floor joists. (MVLA)

What's in a Name?

  • The word “summer” is derived from an archaic English word sumpter, meaning a packhorse used to carry loads.
  • If you prefer the old French derivation, it comes from a bête de somme, which was a beast of burden or mule.
  • Whichever language you choose, the well-named summer beams carry the “burden” of the floor’s weight.

The New Room

After removing the floorboards of the New Room, Mount Vernon’s Preservation team had the opportunity to closely inspect the room’s surviving east summer beam.

The New Room originally featured two summer beams, situated on either side of the chimney stack to provide stability. During framing repairs in the late 19th century, however, it appears that the room’s west summer beam was removed and never replaced. Examination by the Preservation team revealed that the remaining east summer beam was not original to Washington but rather replaced during repairs in the early 19th century.

To confirm this suspicion, the team employed dendrochronology—the scientific process of dating wood by analyzing growth rings. The results pinpointed the beam’s origin to 1838, decades after Washington’s death. 

Dendro on Summer Beam
By taking a wood core sample of the summer beam, the Preservation team was able to use the science of dendrochronology to date the beam to 1838—39 years after Washington’s death. (MVLA)

Scheduled for Replacement

Knowing that the beam did not date to Washington’s era, the team decided it was best to replace it (and its missing counterpart) with steel beams. "We are very careful where we use steel in a historic wood frame," says Director of Preservation Tom Reinhart, "but it was needed here to improve the floor’s structural integrity." The new summer beams will better withstand the weight of and vibrations caused by daily visitors and will allow the team to eliminate supporting brick piers that were later additions in the Mansion cellar. The steel summers will be sheathed in wood so as to appear as the originals did.

Director of Preservation Tom Reinhart (left) and Assistant Restoration Manager Steven Fancsali inspect the New Room’s summer beam. (MVLA)

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