Tuesday, January 13, 2015

A Barn and its Daisy Wheel


Not a very neat daisy wheel is it?

About 8" across, it was found during the dismantling of an upstate NY barn, c. 1790, scribed onto a board used to sheath the roof. The lines were drawn with the pin of a divider, not a marker. They can be seen in a raking light.The board is still in its proper place. This is a tracing made of the pattern carved by the pin of the divider.

The barn is probably the first of 4 connecting barns, c.1790. Green Mountain Timber Frames recently dismantled, repaired and sold this barn for reuse along with the barn I wrote about in December, 2014. http://www.greenmountaintimberframes.com.

It has modified gunstock posts, a 5 sided ridge pole, rafters spaced 38" on center.

The daisy wheel determines the framing layout for this barn.

The petals are not important. They are just the arcs of the radii. The tic marks around the circumference of the circle are what counts and the lines - the spokes - which connect those marks. The wooden board with the daisy wheel was the template, the reference for lengths and relationships. When it was no longer needed it became sheathing.

The master carpenter rotated the daisy wheel first with one diameter (2 'spokes') vertical and then with one diameter horizontal. He used all 12 points and spokes.

So how did the carpenter begin? He and the farmer knew the approximate size and location of the proposed barn. He decided on a width and drew his daisy wheel.

The diagrams show how to start with a length  -line A-B - and create a circle whose circumference runs through those 2 points.

Swing arcs the length of the line -  A-C and B-C drawn in red. C is the center of the circle. The arcs mark the 6 equal point on the circle and make the daisy petals. The dashed green lines are the spokes.            
To rotate the spokes, divide the segments in half - extend the arcs - C-B-D - so that they meet . The line C - D  is the rotated stoke extended. The daisy wheel rotated is drawn in black

Here's the floor plan, a 22 ft. by 32 ft. rectangle that uses only one daisy wheel. The plan is outlined with double black lines. On the left end the line between 2 points on the daisy wheel is 22'-0" wide. The red spokes are the daisy wheel. The green lines connect every other spoke. Where they cross marks 32 '-0" in length.

The framer had the size of the barn. Next he needed the height of its walls. He knew that a daisy wheel could become a 6 pointed star. I have drawn it here. He knew that 'A-B' was his width,- black dashed line - and that he needed 'D-E'

Here is how he could have laid it out on the barn floor.

A-B is the width of the barn. Use that width as a radius to draw 2 arcs. They meet at C. The green lines which connect A,B. and C make one half of the 6 pointed star. Then he could swing arcs from each point. The intersections of the arcs gave him second points so he could draw straight lines A-D and B-E.  They cross in the middle of the triangle which is the middle of the 6 pointed star, the daisy wheel.

A-B-D-E is the size of the barn's end and interior bents.

Below is the layout of the interior bents: first the daisy wheel with vertical axis defining the rectangle - dashed red line; then the daisy wheel rotated, the rectangle defined again - dashed green lines - and the location of the cross girts located -  see the green circles.

The gable ends of the barn fit neatly into the daisy wheel geometry. The rectangle is defined by the 'vertical' wheel, and the cross girt location by the center of the wheel - horizontal dashed green line .

The gable's ridge is 22' high.  22' is also the width of the bent, the side of the square which enclosed the gable end -  square laid out in green dashed lines with diagonal.

The 32 ft  east and west  walls may have began with the center bay. It laid out the door and the center aisle.
The farmer and the framer must have had a good idea how large that door needed to be. A square centered on the wall would have been simple to lay out.

Each side was laid out with girts similar to the end walls and the 2 bents.The red dotted line connects the 4 points of the daisy wheel to make a rectangle.

To make the daisy wheel application on each side of the central square clearer I have drawn the center square in red, and added green circles at the centers of the daisy wheels.

I also added a small green circle where the diagonals of the daisy wheels cross to mark the height of the braces.

The cross girt - the header above the barn door - is placed on the intersection of the diagonals of the 2 daisy wheels. Here one daisy wheel is drawn in red; the other, rotated, is in green. A small green circle marks the intersection.


I have rewritten this post 4 times as I see simpler ways to design with a daisy wheel.
So far, the diameter of the wheel found on the sheathing  - 8.1" - does not seem to be germane to the layout. It is a marker, a guide.
8"+8"= 16". 16" stepped out 3 times is 48", or 4 feet. The barn is 32 ft long.
8.1" stepped out 6 times would be  4.6 ft.  8 x 4.6 ft. = 36.8 ft.
5 x 4.6 ft = 23 ft.   The barn width is 22 ft.

I need to borrow Dr.Who's Tardis. I want to talk to this framer.



Saturday, January 3, 2015

Just 2 Squares: Geometry in Construction, c. 1917

This house, c. 1917, once sat on several wooded and landscaped acres. Today that land has become a modern subdivision.

The house's owner and I stood in the front yard last fall, considering repairs. He asked why his house looks and feels so much better than the new Neo-Colonials which surround it. He knew his house had presence the others lacked, but wondered exactly why.

We talked about  the obvious things: His house is sited to be seen as one comes to it, its porch inviting.  The new houses' front doors face the street; however often a visitor's introduction to a house is at its garage. Cars first, people later.

The new houses have doors and windows of varying sizes with skimpy casings. They have 3 or 4 different eave details.  Lots of things to look at but no unity or focus.

This house uses 3 window widths, all the same length with the same sash and panes framed by generous casings. The entrance sidelights match the windows in length. The porch and house share eave details.  The centered bay window, the double windows above, the triple windows below, the porch columns, even the minuscule, almost non-existent corner boards, all focus the viewer's eye on the front porch, the entrance.

I told the owner I'd try the geometry of his house to see if it contributed to the sense of wholeness and calm which his neighbors' houses lack.

I was not sure his house used geometry; I had not explored geometry on houses build after 1860.
However, I had measured much of it and - as is clear from the photograph - it was symmetrical.

The house uses a basic geometry: the square.

The front facade is 2 squares. 
The sloped lines are the diagonals of the squares.

For clarity I have only laid out the geometry for the square on the right side.
The diagonals define the center of the square and simplify dividing the square into 4 equal smaller squares. The horizontal center line ( red dot and dash line) determines the height of  the porch roof.
The vertical center line may be one of the determining lines of the 3 mulled windows. The windows are also centered in the rooms; that center-line may have been more important to their placement.
 And see my paragraph below*.

The porch's width and height come from the first squares. The square of the porch is directly related in placement and size to the double square of the house.

Divide the squares into even smaller squares and the center of one is the center of the sidelight.

In the triple sash on the left I have superimposed a square with the diagonal extended. It doesn't fit.

However, looking at the photograph of the house it is clear that it is the complete window with its casing that we see. When a similar square with extended diagonal is drawn over the casing of the window, it almost fits - within 1-2".

Hmmm, I could have missed part of an inch here or there... My work for this house doesn't require changing windows. I measured them from the inside to get a sense of the rhythm of the space. I probably wasn't accurate enough.

* 2 geometries which expand a square are
 The Square Root of 2 - using the diagonal of the square as the length of the rectangle (red lines) and
  The Golden Section - using the diagonal of half the square to find the length (green lines).
 Beginning with the left hand square I have drawn and labeled both.  They mark the center and the width of the triple window.

A careful look at the photograph will show that the right hand triple window is a modern replacement that's not the right dimensions. This window will be restored to its original proportions.

Friday, January 2, 2015

House to save!

WHOM  do you know  who is just yearning for a c. 1780 western  Vermont farmhouse with a pristine post and beam frame?
The house itself is quite plain inside, fitting to its time and place. There are few parts to salvage beyond the frame. perhaps the clapboard and brick, doors and hinges. The window sash are c. 1900 or later.

HOWEVER:The frame is chestnut with gunstock posts. It could be exposed to the roof if an owner wanted.


I will be measuring and analyzing this house on Monday - if the roads from here to there aren't too icy.

More later after I have dimensions.