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Researching the Fortress of Louisbourg National Historic Site of Canada
  Recherche sur la Forteresse-de-Louisbourg Lieu historique national du Canada

DOMESTIC BUILDING CONSTRUCTION 
AT THE FORTRESS OF LOUISBOURG, 1713 - 1758

By

Eric Krause

1996 Draft Report

(Fortress of Louisbourg
Report Number H G 10)

CHAPTER FIVE

EXTERIOR WALL FINISHES

The Louisbourg climate was harsh and varied: temperature, while moderate compared to the Canadian interior, would fluctuate widely, producing destructive frost/thaw cycles; cold summer fogs moving in routinely from the sea would mean that dampness would never entirely disappear; and winter gales springing up suddenly would drive rain, snow, sleet, ice or spray against a town built on the edge of the Atlantic Ocean. Building damage mounted yearly and repairs were excessive. Some traditional protections failed and new ones were tried in a frantic attempt to save investments, and the face of the town of 1713 quickly changed.

The common protection in the early years, the covering of an exterior surface like a wall or chimney, first with an earth-based or a lime-mortar-based finish, followed perhaps by a limewash (whitewash), or perhaps even paint, took two forms: crépi or crépissage, the rough coat applied either as a preliminary or as a final covering; or enduit, a crépi more expensively refined through a screen, to produce a final, fine, uniform finish less apt to crack, and technically, though not always, trowelled over a crépi.

Local clay, suitable and inexpensive as an earth-based finish, by itself would have demanded constant attention since it lacked staying power, and so a builder sometimes combined it with lime. This combination was only a slight improvement, and a rendering based solely on lime proved to be more popular. The common recipe was one part lime to two parts sand, but did not include directions regarding thickness or precisely how much of a wall to cover.

Louisbourg kilns provided a relatively inexpensive source for the lime. Gypsum, found in great quantities on the island, was also the base for some renderings. An enduit en plâtre, however, was rare and specifications reserved its use to inside work alone.

A mortar rendering, done in 1721 at government expense, followed the complaint of Father Hilaire, chaplain to the Louisbourg troops, that he could virtually see the outside through his piquet walls. Yet, it was not every owner who would render his piquet home, and some left caulkings exposed both within and without.

Building views also suggest the sparing use of renderings on piquet structures, revealing visible joints and the occasional rounded piquet. Had these owners used only enough of a crépi to cover the caulkings alone? In contrast, views of charpente buildings, certainly some with piquet infilling, illustrate structures with exposed framing members but with hidden fills.

With laths, it was possible to maximize the degree to which a wall might be covered. In Port La Joie, in 1733, small exterior laths, to which was applied an enduit of lime and sand, were to be nailed to the framing members of a charpente building. The contract noted that this was a common practice (inexplicably the plans themselves show framing members). In Louisbourg, in the case of an early administrative building, the lathing was both inside and out, and the fill piquets with a lime and sand crépi.

In contrast, the English style of lathing differed noticeably from the English method. In 1749 the French authorities, now returned to Louisbourg following the English occupation, found the prefabricated charpente fame of a large imported New England barracks standing incomplete in the Queen's Bastion. Ordered to apply the exterior lathing in the English manner, Louisbourg's carpenters probably had little difficulty in proceeding, given that a trickle of New England frames had been arriving in Louisbourg since as early as 1732.

Rubblestone structures also required the protection of a rendering, traditionally a jointing or pointing procedures, known as crépi à pierre apparente. As the name suggests, the crépi shielded bonds and bedding joints while leaving a degree of the stone exposed. The greater the amount of crépi the less the face of visible stone.

Not until 1726, as stone structures and fortification walls took form, did a contract mention the use of crépi for rubblestone. Ganet, the king's contractor, concerned about proper payment for past and future work not covered in his current contract, had demanded clarification. Shortly afterwards he received a new agreement that included payments for crépi à pierre apparente and for two less frequent but more expensive lime and sand renderings - a rustic crap finish by itself, or a polished enduit to follow.

In Europe a limewash often followed an exterior crépi or enduit, although the degree to which this practice was followed on Isle Royale is unknown. The standard military recipe for limewash in Louisbourg specified two coats of lime slaked that day, with the second, containing glue, to be applied only after the first had dried. Unfortunately, these specifications were meant for interior crépis and enduits only (and never for wood). Nevertheless, the description of a Block 15C house as "in a very bad state without any whitewash" was perhaps an indication that exterior limewashes were somewhat popular.

Mortar and non-mortar renderings were no match for the Isle Royale climate, particularly when questionable techniques such as salt in the mortar reduced their effectiveness to an average life span of just three years, and expensive annual repairs to both fortification works and king's buildings became the result. By the early 1730s the situation with bonds and caulking had reached a critical state; for example, a 1734 military report commented upon frost action on Isle Saint-Jean and concluded that it was becoming too costly to replace the earthen caulkings that were routinely falling from buildings each year.

It was, therefore, inevitable that a change in technique, the introduction of the beveled weatherboard, occurred. The course of change was also evolutionary. In 1715 a general inventory of the Newfoundland buildings that the Isle Royale colonists had abandoned in 1713 had listed over 200 wooden structures, mostly piquet. At that time, only one building - newly constructed - was sided with boards (of oak).

The beveled weatherboard, although used as a sheathing beneath clapboards in New England, at least as early as 1700, likely evolved in Louisbourg out of local roofing techniques. By 1713 Newfoundland builders had switched from laths to boards as a sheathing for wooden roofing shingles. In Louisbourg laths again reappeared, and boards too, with butt joints, but as a sheathing for slate and shingled roofs they were a failure. Then, in the 1730s, the beveled roof sheathing board appeared, along with the beveled weatherboard.

The military establishment at Louisbourg, unlike the inhabitants of the town, were slow to adopt the beveled weatherboard. As late as 1739 Governor DeForant and commissaire-ordonnateur Bigot were still complaining about the effectiveness of crépissage, while observing that the civilian population had already made the switch to a Boston board cladding to solve the exact same problem. Even into the 1750s military men like engineer Louis Franquet, who nevertheless recognized the protective value of beveled boards, continued to view them as only a temporary measure, to be removed once the masonry had finally dried.

In the town, though, beveled weatherboards were a proven, permanent technique, and despite the numerous examples of clapboard houses which the English occupation forces left behind in 1749, the returning French populace, both civilian and military, continued to use beveled weatherboards throughout the 1750s. Beveled weatherboards were a success, encouraging new, even expensive, constructions of piquet homes (as late as 1754 for example), and allowing for the continued use of piquet as a relatively cheap insulation fill in charpente buildings.

Weatherboards were also a welcome solution to the problem of deteriorating masonry. Consequently, they were chosen to cover both the executioner's brick-filled charpente house and stone and brick-filled charpente residence on 16E; and in 1749, in the guise of beveled planks, became a 67,000 livre proposal to protect the town's masonry fortifications.

In Louisbourg the use of weatherboards was not regarded as an opportunity to dispense with a fill entirely, as was the practice in New England. Perhaps only once, in Block 41, did any Isle Royale builder capitalize upon the technique of a dead air space in between the walls. There, in Block 41, he completed a building with only beveled boards outside and a wooden finish inside.

Louisbourg weatherboards, known locally as Boston boards, a softwood probably pine, occasionally planed but usually left rough, and imported from New England as a board (one pouce thick) or as a plank (2 pouces), were placed horizontally but not in the overlapping clapboard style that was popular in the American colonies. Rather a bevel of 2 to 4 pouces along their lengths (it is not known whether or not they were imported pre-beveled) made for ease of application: the boards were nailed directly to the walls of piquet and charpente buildings, bevel overlapping bevel, to produce a flush finish. Masonry constructions, of course, would have required the added expense of wooden nailers. A cross-section of the Frederick Gate and an elevation of the Block 13 hospital illustrate weatherboard characteristics quite clearly.

Beveled weatherboards were, technically speaking, both adaptable yet limiting, in actual application. One builder, in Block C, chose to cover the foundation of a charpente building with 2 pouce planks, the main and lower gabled walls with one pouce boards, and the upper gables with 2 pouce planks. Another, in Block 20G, placed weatherboards everywhere except on the foundation. A third builder, in Block 5A, decided to protect the ground floor walls of a 2 1/2 storey charpente building with 2 pouce planks, but on the walls above he used one pouce boards.

In contrast, weatherboards with bevels would not have been suitable in vertical applications such as suggested by two houses palissadée de planche in Block 37D. Boards or planks with tongues and grooves instead, always in good supply at Louisbourg, would have proven more weatherproof. Was it such a circumstance then, the requirement for a vertical wall cladding, that prompted the use of tongued and grooved boards and planks on a variety of royal and private structures? - a winter lean-to over the governor-occupied engineer's house, several Royal Battery charpente sentry boxes, the first engineer's house in Block One (to close off the open partitions to the elements), and a Block C building (the upper gabled end only, in contrast with the wall below which had English beveled boards).

Weatherboards, whether applied horizontally or vertically, or shingles, were natural choices for the upper triangular gabled areas of roofs. At 14E, one pouce thick boards were nailed to the upper framing members. For the charpente executioner's house, the shingled upper gable would have contrasted markedly with the beveled boards walls below. At 19B shingles over Boston boards covered a lower gabled wall (and perhaps the upper as well), while Boston boards alone were reserved for the remaining lower walls. At Baleine, the charpente church there had shingled upper gables but an exposed piquet  fill and frame in the walls below.

It is not known if builders routinely infilled the upper gables prior to the placing of weatherboards or shingles. A few non-weatherboarded piquet building views illustrate piquets at these locations, but those contacts that called for weatherboards, suggest, albeit ambiguously, that builders did not always first insert a fill.

The military, which was to bear a remarkable expense in their attempt to solve their maintenance nightmare, not only owned the majority of masonry structures (private individuals were to build but a few) suffering from mortar failure, but also had to face the added cost of wooden nailers before it could ever begin to repair them. Yet, as engineer Boucher argued (and lost) in 1750, concerning the lighthouse, beveled boards were the only real solution. The structure had to be either covered in planks or he would be facing the enormous cost of a maintenance cycle that had no end: erecting scaffolding, repairing structural damage, replacing crépis - every four to five years. On the other hand, a 1744 repair of the masonry barracks of the Island Battery had demonstrated that Boston weatherboards, at three times the cost of a single rendering of crépissage à pierre apparente, were themselves an expensive initial proposition.

A proper retrofit of masonry with beveled boards or planks, according to military specifications, meant not only the use of wooden nailers but, significantly, the added task of embedding them in the rubblestone. Iron cramps were to fix them firmly. Embedded nailer dimensions and spacings varied: 4 by 4 pouce common rafters or 7 by 8 pouce pine timbers, for example, were usually spaced 4 pieds apart; though in one case the distance was 4 pieds 10 pouces. Planks not exceeding 12 pieds in length, or 14 pieds 6 pouces (given the use of four vertical nailers) or 9 pieds 8 pouces (three nailers) of at least one pied in width, fastened by two 6 pouce nails to a nailer, were acceptable.

Some military variations included half-laps rather than bevels, and possibly no embedding of nailers at all if, for example, a building wall were only one pied 6 pouces thick. In this case the nailers were probably fixed with iron clamps against the wall, not unlike the procedure for the interior finish of a certain powder magazine. Embedding, quite obviously, would have weakened any wall and, in fact, was a technique of which the minister of marine, Rouillé, was quite critical. He believed that the practice of embedding the nailers in fortification works, which was done, he believed, to prevent the enemy from using them to scale the walls once the wooden facings had rotted away, was causing more damage to the walls than if no protection had been taken in the first place.

The engineer, Franquet, disagreed, inferring that previous Louisbourg engineers had shown a total disregard for quality control in the construction of masonry works, and so wooden facings could not but help. Certainly a wooden covering would allow the original mortar to at least dry, preventing further buckling. However, he did not favour wooden facings on new works; instead he encouraged the use of better materials in original construction.

Exterior painting was always a possibility in Louisbourg, but in reality a lack of sustained military or civilian commitment to the idea and a continued problem with supply meant that painting was not general practice. Usually in short supply - 1742 was a possible exception - the paint was to have come from France, but one year, 1743, the supply had all leaked away on board ship. In fact, that year there was no paint at all in the colony.

For certain, the military wanted to paint all its exposed wood, a deep red - for reasons of protection rather than aesthetics - all doors, shutter, [window] frames, gates, railings, sentry boxes, gun carriages, even iron cannons, but it did not make this plea until 1739. By then the problem with rot was critical. In fact, a series of 1736 Louisbourg contracts, for the maintenance and repair of crown-owned buildings failed to even mention paint (unlike a similar 1733 contract for Quebec).

Only a few individual examples besides the 1739 plea mention exterior painting in Louisbourg at all: two coats of red oil paint (the recipe: 40 livres of oil, 20 livres of red [ochre] for the pigment) for the windows of the lighthouse and/or lighthouse keeper's house (1731 - military building); Duhaget will see to it that the first coat is applied this year, and Augier will apply the second coat in the following year (1753 - private home).

In 1741 the engineer wanted the commissaire-ordonnateur to approve a new contract with the entrepreneur, that included payment for red paint. The clause, however, did not appear in the 1742 amended contract. In 1744 the authorities paid for the services of painters. The low charges, however, suggest that it was for minimal work. The conclusion: exterior painting was not generally practiced at Louisbourg. Even private building contracts, even those sufficiently detailed to provide precise details on the size of bevels for the weatherboards, did not include any rider concerning exterior painting.