Please see Part 1 for the history of the Beatty-Cramer House in Maryland now owned by the Frederick County Landmark Association.
The Beatty house was built in the 1730's. The Cramers encased that house with a new one about 1850. These posts focus on the first house, the Beatty House, which is inside the house in the photograph.
The first post:https://www.jgrarchitect.com/2019/11/beattie-cramer-house-and-its-daisy-wheel.html
This daisy wheel and the 3 petals - the 'eye' - were found on an original stud on the 2nd floor frame of the Beatty House.
I was asked to explore how the diagrams could have been used to lay out the frame. This is part 2 of my report.
The Beatty Cramer daisy wheel with its 3 petals, its 'eye' in red,
showing how they are part of each other.
This daisy wheel was found on an upstate NY barn built about 60 years later. Note that it is not perfect, as the one I drew is not perfect.
The diagram in the Beatty Cramer House is just that - information for the builder.
The diagram on the barn sheathing was also information.*
Neither daisy wheel needs to be perfect to be useful. It's a 'setting out' tool, a record, notes to the builders and those who will work on the house later.
My first blog post laid out how the master builder would have used the 3 petal diagram to lay out the width and length of the house, the size of the 2 rooms up and down, and the location of the bents.
A bent is a part of a timber frame , the posts and beam, that runs front to back.
This photograph shows 4 bents about 4 feet apart in the east room, first floor. The beams hold up the second floor . The posts extend above the floor of the upper room to the plate . The second floor on the east side of the house has half walls.
The second photograph shows how the west side of the house was originally stepped down. See the tie beam which is being photographed in the center of the existing wall on the left. That beam was part of the floor frame for the west side upper room.
The drawing shows the east and the west end elevations. The floor and wall frames that were part of the Beatty House can be determined by the mortises left behind when the frame was changed. The pitch and frame of the roof, especially the east end, is not as easy to ascertain.
The master carpenter has his first dimension: the width of the house, and he has left us his note about how to apply that dimension: the red line at the right is the width of the house. The arcs of the eye is the way he sets out a square, finds his next dimension.
A note about laying out the daisy wheel to find the next dimension: the carpenter could have used a Line to draw the arcs. He could also - when he wants square - have used a long compass like then one shown to step off the dimensions. Every rectangle could be trued by checking the diagonals, as framers do today.
The framing elevations
First the west end - the frame on the right in the drawing above.
The width of the house becomes the radius for the arcs that determines the height of the bents. The tie beams and the plates are set where the arcs cross This is the same geometry that determined the floor plan of the house: the 3 petals of the daisy wheel, the eye - see the previous post.
The height is divided in half to determine where the 2nd floor will be located.
The plates extend from this west side of the house to the east end. The builder has to work with that height. See the red arrow from the west to the east elevation.
The east rooms are a few feet higher than those on the west. How did the builder set that floor height?
He may have used the height where the diagonals cross the arcs to place the 2nd floor of the east side. See the black dashed line. The daisy wheel could then have set the sill location.
The edge of hearth in the 1st floor west room also uses those points.
Or perhaps the difference in height was set by daisy wheel from the beginning.
The house was built into the slope of the land. The simple way to excavate the storage cellar under the east rooms could be by digging into the hill from the west end. The kitchen on the west needed to be only a few feet above grade - for easy access to the spring house. The formal chamber on the west also needed to be a few feet above the grade to keep the wood sills dry.
I have indicated the slope of the land with a black dashed line below the framing drawing of the north elevation. The grade on the west (left) side is as seen today. The grade on the east (right) side would have been at least 12" below the top of the stone foundation.
The dirt removed to create the cellar hole could have been been used to level the area on either end.
The diameter for the daisy wheel for the west rooms is the height from the sill to the plate.
The daisy wheel is drawn with its axis horizontal to show the location of the second floor joists.
The diameter for the daisy wheel for the east rooms begins at the sill and ends above the plate. The petals of the daisy wheel are located at the underside of the plate. Here I have drawn the daisy wheel with its vertical axis. The builder would have begun his layout from the under side of the plate, which was a given.
The daisy wheel on a horizontal axis could locate the plate for the east 2nd floor ceiling. The braces could have extended to that height. The petals already locate the studs on each side of the fireplace.
The roof ?
It's not there. Nor is the ceiling height for the east 2nd floor chamber. Only an original window location, the stud locations, and a brace with an angled cut from a reused collar beam remain. I have extended it here.
2 roof pitches have been proposed.
One, shown here, matches the Jan Breese roof built c. 1723, in New York State.
That roof would be based on the daisy wheel and a second interlocking circle. It is not a diagram used for other parts of this frame.
The roof pitch could also be based on the eye - or as described: rafter length 3/4 the length of the roof span. The arc of the width of the house fits the lower pitch.
The arcs have arrows. I have added the roof line.The plates are red.
I prefer this pitch because it comes from the geometric notes the builder has left for us. It is consistent with his overall layout.
It is time to look again, on site, with twine to mark the dimensions, swing the arcs, and especially, consult directly with the members of the Frederick County Landmark Association.
*How that daisy wheel was used is in my post: https://www.jgrarchitect.com/2015/01/a-barn-and-its-daisy-wheel.html
Post a Comment