Facts and Figures about Cobblestone Masonry:
"Across the northern half of America, from the Atlantic to the Rockies, the Ice Age left a colossal hallmark upon our landscape."
-United States Department of the Interior
Ice Age National Scientific Reserve,
A Proposal for Cooperative Conservation
Our Cobblestone Heritage
As cited in Details of Cobblestone Masonry Construction in North America 1825 - 1860
What are they?
Boulders, cobblestones and pebbles are a glacial legacy shared by our northernmost states and Canada. Glacial action left an inexhaustible supply of rounded stones. Even today, 12,000 years after the retreat of the glacier, wave action along 8,117 miles of Great Lakes shorelines continues to polish boulders into cobbles, cobbles into pebbles and finally pebbles into sand
- taken from Dana Thomas Bowen's book Memories of the Lakes (Freshwater Press, Inc.)
by Delia Robinson
The uniqueness of American cobblestone construction lies in the manipulation and refinement of the mortar treatment. One European precedent to American methods can be found in southern England, along the Sussex Coast in the vicinity of Brighton, Worthing and Shoreham. There, as early as 1750, buildings were constructed of rounded beach flints laid in rows with horizontal mortar joints troweled to a flat projecting "V". In discussing English flint work, Sydney Jones, in his book The Village Homes of England (1912), remarks, "By acknowledging tradition, by treating with respect the memory of former things, the craftsmen did not yield to mere copy ism but added their own stamp and so gave their work a living sturdiness and vitality; they gathered together the bequests of their forerunners and clothed them with their own thoughts." This can just as appropriately apply to American cobblestone.
How can I identify a cobblestone building?
Cobblestones are laid in horizontal rows with decorative mortar treatment to the horizontal and vertical joints.
When were cobblestone buildings constructed?
In general cobblestones were built between the completion of the Erie Canal and the end of the Civil War, 1825-1865.
How many cobblestone buildings were constructed?
It is now believed that between 1,000 and 1,200 were constructed in North America.
Where were these buildings constructed?
The cobblestone building style began in New York State and spread westward to Ohio, Illinois, Michigan, Wisconsin and into the Canadian province of Ontario. There are also a few built to the east in Vermont
Where is the greatest number of cobblestone buildings?
Ninety per cent of the cobblestone buildings can be found within a 75-mile radius of Rochester, NY.
What is a cobblestone?
The word ‘cobblestone’ comes from the Middle English ‘cobelston’. The word came from ‘cob’ meaning a rounded lump and ‘stone’ meaning just what it means today. Geologists classify cobblestones as being 64-256 mm or 2.5 in to 10.1 in. In lay terms, a cobblestone is a stone that can be held in one hand.
What was in the mortar?
The mortar is soft-lime mortar. It was made of locally dug sand, powdered lime and water.
How was the lime made?
Local limestone was broken into pieces, burned in a limekiln, and then slaked with water to form a powder or paste. Slaking was the process of placing the hot limestone in water, which caused a chemical reaction in which the limestone becomes a soft powder.
Perch – 16 ½ cubic feet of rubble stone
Cord – 99 cubic feet of stone in the wall
Joint – The division between the stones; there are two kinds horizontal and vertical
Pointing – the process of filling joints with mortar
Bead –Projecting ½ circle of mortar about 1” wide to embellish the joints
Course – each horizontal layer of stone in the wall
Quoins – Large squared corner stones
Stone boat –flat sled drawn by horses or oxen on which to collect stones from the fields
Sorting Board – a plank with a few holes of various sizes through which cobblestones were sorted
Bee – Gathering of people to collect and sort stones
There were at least three construction methods.
The first was a simple rubble wall, with layers of glaciated cobbles interlaced. The outside showed regular courses, while the inside was random. This was used in the earliest construction.
The second was a rubble core with a facing of smaller lake-washed cobbles, which included longer bonding stones reaching into the core. The facing stones showed perfectly matched faces, yet the stones were of irregular dimensions. This was popular through the 1840s.
The third utilized a rubble wall laid first and then with a cobblestone veneer laid up separately. In this method the stones were small and there were no bonding stones in the veneer layer. This technique is evident in the latest constructed buildings.
Building a cobblestone house.
The following is an excerpt from the memoirs of Henry Lee whose family built the house (1844-1845) on Minsted Road, Arcadia, Wayne County, NY. It was taken from an essay by Verlyn E. Klahn on Wayne County cobblestones. The essay was published in the December 15, 1955 issue of the Newark Courier-Gazette. The essay is on file at the Cobblestone Resource Center.
“Father had accumulated a large quantity of stone and lumber. On the last sleighing that spring there was a “bee” and a large pile of sand was taken from the back of the woods where Mr. Farnsworth’s farm now stands. . . it being the first ever taken from there. We got two or three loads of cobblestone from the lake for facing of the wall. The “cut-stones” (caps and sills) came from Phelps (then Vienna). The job was let to a Mr. Skinner. . . have forgotten the price but I think it was less than $200. They came and laid the cellar wall; then went away and did other jobs to let this harden; then returned and laid the first story; then went away again for several weeks and so on until it was finished.
The first stone he drew from the lake, he took a man with the team and went to the bar off the bluff across the bay on ice. I went with him and we reached home about one o’clock in the morning. Father went about 20 times but sometimes being rainy he got only part of a load and often reached home 10 or 12 o’clock at night”. According to the son, his own hands and the hands of his father became so sore picking up stones that they had to bandage them. Sometimes the stones were so heavy that they had to dump some from their load. Also, since their horses wearied easily under the heavy load, they frequently had to stop and un harness the animals to rest them before completing the trip.
“In laying the walls after getting out of reach from the ground there were poles set about 6 or 8 feet from the wall and about as high as the walls were to be, then long poles were lashed to them with hickory withes an inch or an inch and a quarter in diameter and six to eight inches long and then scantling laid across them to the wall and planks laid on them making scaffolding all around the house. Then a crane and tackles and rope were fastened to the northeast post. Buckets a little larger than a molasses cask cut in two would be filled with either mortar or stones and hoisted up, using a horse, to the scaffold and their contents distributed with a wheelbarrow. When they were above reach from a scaffold the staging would be raised again. . . “