Preservation Carpentry: How to Accurately Restore the Sherburne House at Strawbery Banke

Hi Everyone!

    My name is Libby Ware and I am a rising senior at the University of Rhode Island majoring in Anthropology and Spanish and minoring in Political Science. For the 2022 Summer Field School, I chose to focus on preservation carpentry. Preservation carpentry is the craft of carpentry applied to historical buildings in preservation and restoration projects. The goal of preservation carpenters is to achieve historical accuracy in their craft. 

    In my study, I focused on the window lead cames, bricks, slate roofing, and window glass recovered at the Sherburne site during both the original excavation between 1977 and 1983 and later in 2019. 

    When looking at the bricks, the goal was to determine if the bricks recovered from Sherburne were produced at the nearby Toogood brick production site at Strawbery Banke, or put in later. The Toogood bricks were larger than the bricks recovered from Sherburne used at the time with their measurements being 8-9x4.25-4.5x2.25-2.5. This was one of the easier things to determine in my study as I measured the brick and it was the slightest bit smaller at 8x4x2.5. This leads me to believe that these bricks were installed in the 18th century when an addition was added.

Pictured above is one of the bricks recovered from the hearth.

    The slate roofing was an area of interest as the current roof is asphalt. Slate lasts 125-200 years which makes it hard to date but we can still learn from it. According to CopperWorks' "The History of Slate Roofing," slate roofs did appear in the 1600s but the first quarry did not open until 1785, and slate was not mass quarried until the later part of the 19th century. At the site, a burnt slate was recovered indicating a possible fire. When looking at the Portsmouth Fire Department's Historical Records, I learned that there was an "incendiary fire [that] consumed entire contents of a barn owned by Samuel Sherburne at the Plains," on December 10th, 1804. While trying to figure out where this fire took place, I read an article from the time of the fire that was converted to an online article at Seacoast NH that described an arsonist, or as Brewster put it, an "incendiary," that set multiple fires in December of 1804. Although Samuel Sherburne is part of the same family as that of the Sherburne House, this fire took place at a farm they owned outside of town at the "Plains," and destroyed two barns, one containing valuables and another containing livestock.

Above are pictures of burnt slate recovered at Sherburne.

Above is an example of a regular slate.

    My main focus was the window lead and how to identify potential dates and/or names on the heart as seen on the Jamestowne Site. In order to be able to do this, I first had to soak the window lead in apple cider vinegar to loosen the rust that had built up over the years. Then I used a dental pick and tweezers to carefully unfurl the window lead. I did not uncover what I thought I was going to. Instead of a date or name, there were uniform lines inscribed on the heart. 

The above images are pictures of the window leads in relation to a scale bar.

These are closeups that show the slight line indentation in the lead,

        Upon more research, I was able to identify these lines as a quality control technique for window lead makers from this article. Additionally, I was able to determine the type of came, a flat lead came. 

A wide variety of came has been used for ornamental glass in America: (a) flat lead came; (b) round lead came; (c) “Colonial” zinc came; (d) double-heart lead came with a steel core; (e) “Prairie School” zinc came.

Original Site

   One of the issues faced when trying to restore Sherburne is that the windows, like other features of the house, were altered inaccurately in the early days of Strawbery Banke's ownership and it has been difficult to determine what type of glass diamond was utilized originally. 

    When looking at the number of window glass fragments uncovered at Sherburne, I was able to find one mend in the devitrified, meaning diseased, glass. In this single mend, there are three edges visible meaning we are now able to determine the shape of diamond used for the glass panes. There are lines indicating window lead presence along the edges.

Above is a magnified image of the glass showing the line indicating window lead.

Above is the mend pictured in relation to a scale bar. 

    I hope that my contributions through this Field School provide a better understanding of what Sherburne was like when it was in its original form and help clarify previous uncertainties surrounding the window panes and lead cames. It was a bonus to be able to piece together the history of the fires in Portsmouth during the early 19th century and the Sherburne family and their property.