Senior Housing Renovation Supports Local Timber Suppliers
Carpenter and writer Adam Miller recently completed the timber framing portion of a barn that is undergoing renovation in Lyme, New Hampshire. The project is part of a small senior housing development next door to the Northern Woodlands office. Staff here have been watching with great interest the changes to the post and beam barn and the adjacent main house. Notably, property owner Ray Clark is focused on supporting local sawyers and loggers, which has a ripple effect on the local forest products economy.
We caught up with Adam while he was at work next door. He explained the two layout systems often used in timber framing: the scribe rule and the square rule. The scribe rule originated in Europe, where mass deforestation limited most people’s access to quality timber. The best wood was typically reserved for elites, and sovereign uses such as ship building – leaving smaller and irregular timbers for use in building residential and agricultural structures. Scribing is very labor intensive; the builders draw out each assembly for the house or barn at full size, and stack the timbers oriented over the drawing. The use of odd shapes of wood allows for beautiful joinery between timbers, but nothing is interchangeable. Everything is unique. (See Framing with Ancient Timbers: Scribing Together History in Northern Woodlands, Autumn 2022).
“When European colonists arrived in New England, they found more forests and timber than they could imagine but faced a chronic shortage of labor. So, over time, innovations in timber construction developed the square rule which became the dominant style of timber framing here in the United States – and the basis of the original barn construction,” said Adam. “This method allows all joinery to be laid out by square and measure on individual timbers, rather than requiring assembly beforehand, and many of the components are interchangeable.” (In square rule, layout is accomplished by squaring off reference faces and measuring along the length of the timber).
The barn renovation next door to the Northern Woodlands office integrated new, locally harvested and milled timber with much of the original hand-hewn framing. For the barn renovations, Adam worked with local white pine from Mike Gendron, of Mike’s Custom Milling in Newbury, Vermont.
“This barn has been heavily modified in the past. You can see where the tie beams were lowered to accommodate hay storage,” said Adam. “And these beams were never meant to be seen – after the square rule was developed, nothing was meant to be seen. The frames were plastered over to help houses stay warm. One of the great things about timber framing is that old buildings can have new lives.””
Adam and his crew focused on aesthetics rather than historic reconstruction with this project, since the barn will live on adapted to a new use as a home. A key advantage of cultivating good relationships with local suppliers is that everyone in the process knows what the wood is going to be used for, and carpenters have access to exceptionally beautiful materials.
“Relationships built and cultivated through use of local materials can express themselves in the quality of the materials that we have for different parts of the job,” Adam said.
“Sometimes buildings have all wood everywhere and nothing makes an impression because it’s all the same. Here, the surface treatment gives it some diversity – keeps the various sections of wood surface from either clashing, or simply blending together because it all looks the same,” Adam said. While historic house frames built with the square rule were typically covered with plaster, here the ceilings and timber will be left uncovered to reveal the handiwork and varied textures in the wood surfaces. The decoratively surfaced boards are all hand planed to create subtly different textures on the new wood to give some coherence with the old. This requires decision-making along the way regarding where to transition from the old wood to the new to make it coherent.
The gapping seen between the boards is intentional, part of the aesthetics of renovating with minimally processed materials. An advantage to using lumber processed locally is that it is easier to plane. “In timber framing we use wood materials that are green, not kiln dried. The wood is easier to work, but there is some shrinkage over time. The boards were tight when installed; joining the boards together with splined edges allows the boards to shrink and leave a shallow gap,” Adam explained. “This becomes a design element, keeping the ceiling from being just a monotonous field of wood. The lines between boards allow each to be appreciated individually, rather than taken in as an expanse of wood. Each board has its own character. The lines of boards run parallel to the girding beam that connects all the joists, another way the structure expresses itself. This is a nice way to utilize the particular characteristics of the locally produced material to some advantage. Knowing the characteristics of the material and how it behaves over time is critical to using it to its best advantage.”
Once complete, the house will have two floors above a basement, and the scaffolding is where wrap around stairs will come up from the basement to the first floor, with a landing half way between floors that allows the stairs to turn. Another set of turning stairs will continue up to the second floor. A ribbon of new wood material wraps around the perimeter of barn to balance the presence of the new and old material throughout the structure. “Here, we made a choice to use old timbers to interact with the back wall – these timbers are not original to the barn but came out of the adjacent house. The patina in it was very similar and looked as if it could have been hewn by the same person,” said Adam. “This wood blended in very easily, it wasn’t a struggle to make it match with the old barn wood.”
Looking up from the stairwell to the second floor from the first floor, light floods in from windows. “The play of light on the surface can bring subtle life to a timber frame. Frames that are sanded look a little dull – the pursuit of perfect surfaces makes it seem not alive. Wood was something that was alive, and how it is treated can emphasize some aspect of that life,” said Adam. “The surface treatment can give it a very different feeling, and make it more inviting to interact with in the living space. We’re not trying to create a perfect building. Polished, consistent surfaces may be suitable in an institutional setting, but in a home, the differences in wood make it more inviting, brings the wood to life.”
The image also shows empty pockets where a couple of short joists will be added as part of a small landing at the top of the stairs.
Sawmills are limited in length capacity so it’s hard to get timber longer than what sawyers can cut on a sawmill. Scarf joints can be used to join timbers and to make them longer. These are necessary and functional, but can also be decorative. All the wood used here is white pine with the exception of the wedges and pins, which are red oak. The intent is to draw attention to the two types of wood. “I like this scarf joint because it is relatively easy to cut, has a pair of wedges in the middle that draw it up tight, in addition to the four pins in it, and it’s beautiful,” said Adam.
The image also shows curved reductions in the joists where they connect to the beams. “This is an attractive detail, but actually help the joints perform better in practice because they help prevent splitting in the beam from the sheer force of the load above,” said Adam. “The stress of the load is distributed along that whole curve so that the joists don’t split (the stress would concentrate at the corner of a square reduction, often tempting it to split).”
A close up view of the scarf joint. This is also called the lightning bolt scarf joint in English, arising from the French name: trait de Jupiter (“line of Jupiter”), or the lightning bolt. A pair of wedges are driven, one from each side, exerting even pressure as they expand to tighten the joint. Once the joint is tight, the wedges are cut to be square at the end. The pins are installed after the wedges are tightened up a couple times.
Adam demonstrating the fit of a square rule brace in its corresponding mortise. These were removed from the original barn to accommodate changing the use of the building to a house.
The square rule system uses a lot of housings in mortised members and reductions in tenoned members to get everything to fit together without pre-assembly. Typically, houses built using the square rule would not leave the timber visible, the beams would be covered with plaster. Here, the intent is to keep the frame visible throughout the house when renovations are complete. This image highlights the interaction between the new and the old. The barn was built in the 1840s.
“Decorative chamfering, the bevels along the edge of the posts, is a nice feature for softening corners in the living space,” said Adam.
The work area moved upstairs as Adam was working on the attic framing, and here he explains some of the structural factors that influence his decision-making while timber framing. “Even quite late in the 19th century, builders would hew timber on site to get long timbers like the tie beams and plates here, which help keep the building nice and straight,” Adam said. “I am impressed with how square this barn is because it had a lot of modifications over the years which couldn’t have been good for the structure. The fastest way to do in a timber frame is to have a bad roof overhead or bad foundation under foot – these are the most common vectors for deterioration. Often, failures in a timber frame can be traced to problems with roof or foundation.” A new foundation was put under this barn within the past fifteen years.
This Web Extra accompanies the article Framing with Ancient Timbers: Scribing Together History, by Adam Miller in the Autumn 2022 issue of Northern Woodlands.