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ERIC KRAUSE REPORTS
MY HISTORICAL REPORTS
PUBLISHED ON THE INTERNET
by Eric Krause,
There were six major roofing materials in Isle Royale: bark, wood, slabs, sod, shingles, slate and boards. Slate, however, was not used during the early years of the settlement ...
Wooden shingles eventually displaced both bark and plan materials, becoming the most popular roofing choice in the town. The memoir of 1717 merely confirmed that trend. Shingles already cost one-quarter less than bark as a roofing material and a supply was readily available, first from local splitters working during the autumn and winter, then from New England merchants. By 1751 the engineer Franquet was reporting that the New England shingle was totally dominant, having displaced the local product completely. Franquet, however, was not entirely correct. Periodic shortages were always possible, as in 1756, a time of war, when Louisbourg would place an order for Quebec shingles.
Several factors clouded the question whether there was a standardized approach to shingling at Louisbourg. Sources of supply were quite varied, though the New England shingle did dominate, and proposals that never advanced beyond the planning stage were numerous. Yet there were some common characteristics in all the descriptions: shingles were tapered with a reduced thickness from butt to head, they were placed in equal rows with the length of each shingle exposed no more than one-third, and, beginning in the 1730s they were nailed to a beveled board sheathing. The New England shingle, in particular, was pine, 18 pouces long, 4-5 pouces wide and 4 ligne thick, and nailed with two nails to a shingle. Other shingles varied in description: of oak or white fir, supplied in lengths of anywhere from 12 to 14 pouces; in widths ranging from 5-6 pouces to 9-10 pouces; with a butt of one pouce and a head of one ligne; and nailed either with three nails to oak laths of 4 pieds long, 3 pouces wide, 6 ligne thick, or to Boston boards that were nailed in turn with two nails to each rafter.
The beveled roofing board traveled the same evolutionary course, from Newfoundland to Louisbourg, as did the beveled weatherboard. There, at Plaisance, prior to the 1713 settling of Isle Royale, builders who were versed in the traditional use of laths had already begun to experiment with board sheathings and shingle coverings. This development was out of necessity as neither slate nor tile could hold in the wind.
In Louisbourg, the military, though committed to the use of slate, often chose shingles because of a problem in the supply of slate. Consequently, even the barracks of the King's Bastion was shingled for a time. But in those early years neither slate nor shingles were effective against driven water and powdered snow, and the elements were easily penetrating buildings through the spaced laths to which the slate or shingles were nailed. As early as 1716 then, several proposals were put forth for one pouce thick roofing board (of a type also suitable for floors and partitions) in place of laths. Undaunted, however, royal officials continued to use laths for some time. Between 1721 and 1725, for example, laths and wooden shingles - shingles were by now recognized as superior to slate, particularly in conjunction with laths - were placed on the roof of the commissaire-ordonnateur's residence. The use of laths, however, was drawing to an end, and during this transitional period, in 1723, engineer Verville would recommend boards with butt joints as a sheathing for the barracks roof of the proposed Royal Battery.
Finally, in the 1730s, the beveled roof board made its appearance. Always one pouce thick, in every other way it met the same specifications of the beveled weatherboard. A 1738 memoir also clarified its function: beveled roof boards were a second line of defence against the elements. A tight fit was critical, uniform beveling a necessity.
Beveled boards probably assured the continued use of slate on king's buildings, slate being particularly vulnerable to Louisbourg's climate. No less an example was the Block 1 artillery storehouse. Completed in 1737 the building leaked almost immediately, its slate roof (the type of sheathing is unknown) proving incapable of preventing water, snow or ice from entering. A serious situation indeed, it prompted a call for a replacement with shingles, but the military squashed the proposal, fearing an increased danger from fire ...
[Eric Krause, Domestic Building Construction at the Fortress of Louisbourg, 1713 - 1758, Unpublished Draft Report H G 10 (Fortress of Louisbourg, 1996]
An examination of over 200 whole and fragmentary specimens from excavations suggested that wooden shingles used at Louisbourg during the eighteenth century tended to be:
we should mention that the section of roofing found on lot k of Block 2 (Guion house) included a bevelled board: the shingles are placed on a base of boards with a bevel of 1.5 inches. The boards are roughly 1.4 feet wide ...
... the archaeological analysis of the section of roofing from the Guion house ...
[Richard E. Cox, "Wooden shingles from the Fortress of Louisbourg", Bulletin of the Association for Preservation Technology, vol. II, nos 1-2, 1970, pp. 65-69]
- Standard 16" length, grade "A", eastern white cedar shingles purchased generally from Quebec
- Hand planed at Louisbourg to remove the circular saw marks
- Wide and narrow shingles are culled in order to achieve a more uniform variation of widths
- Hand dipped in wood preservation to increase longevity, and allowed to dry before being re-bundled and forwarded for installation
- Nailed to sheathing using 1 1/2 inch small headed, hot dipped galvanised nails
- Layed with an exposure to the weather of 5 1/2 inches
[Philip Hoad, Technical, Trades & Services Supervisor, Asset Management, Fortress of Louisbourg]