N.B Water penetration
at ridges was a recurring problem
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YVON
LEBLANC ~ FORTRESS OF LOUISBOURG
PROJECTS PAST AND PRESENT
PAST PROJECT
THE
ARCHITECTURAL HERITAGE OF LOUISBOURG
(A General Survey)
Notes for course given
to the University
College of Cape Breton, Summer Sessions
(1977 - Reviewed 1978
and 2001)
CHAPTER TWO
EARLY 18TH CENTURY
FRENCH CONSTRUCTION
Adapted to
Louisbourg Conditions
* This is but a cursory look at some of the practical aspects of construction, with no attempt at being complete
(1) GENERAL
for:Traditional Materials:
Masonry (stone and brick)Wood (pegs, then nails for joining)
Metal (iron occasionally)
Methods: grew from materials.
France 18th century:
- more stone than wood- wood
- wood & stone, or other material for lighter buildings.floors (often):
roofs (all the time)
walls (sometimes)
- depending on supply and work ability.
Workmanship:
declining by this period, compared to Middle-Ages, but still fairly elaborate by present-day standards.
(2) MASONRY
(A) Stone
of work was Deteriorating - same reasons as today:-increasing costs, loss of incentives and sense of work well done. Also - industrial revolution was in the offing.Was it before wood? Hard to say:
Stone has lasted, wood has gone.
Although tools techniques were quite sophisticated anything could be done Quality
- Much rough work under plaster covering.- Final jointing added on stone in place, often ignoring true joints (no evidence of this in Louisbourg)
- Technique influencing appearance:
- Levelling courses- Holes for scaffoldinq, sometimes left unfilled ("boulins")
- Corners: more often cut (or at least, shaped) stone ("Quoins")
- Batter to walls - not always used in 18th century - for stability: slight slope in (+ - 1 1/2" in 12-0) from bottom up
- Walls: Thinner at each floor up.
- in Louisbourg: Some, although limited, evidence of fine cut-stone work: Dauphine Gate, etc.
Chimneys in walls.
Cornices to throw water away from wall.- "Coyaux" - (Bell Roof) to protect cornice, gradually became to be seen as a merely decorative future.
- Metal Bars used for clampinq or reinforcing.
- used by Romans- crampons held in with lead»
- visible on ramparts - especially useful there due to bad quality of mortar.
- Jointing
- originally clay, but mortar (sand & lime) used since Roman times, although clay remains in use occasionally (ovens, fireplaces & chimney~, some mention in Louisbourg sources).- Full ("buttered") joint was normal .- called in Louisbourg "crépissage à pierre apparente" - term yet to be absolutely ascertained, - since "crépi" is actually a coating ("enduit") i.e. rough coat.
(B) Brick
Very ancient material & technique, possibly older than stone.
- It is but mud; in ancient times, dried in sun, later burnt.- sizes varied: Roman, etc. evolved to + - 2" x 4" x 8" - easily handled
- Very flexible material - can be shaped - small size gives flexibility of use.- Some made in Port Toulouse not very good
- some locally made?
- Some imported from New England.Paving brick or tile (little use in Louisbourg, except in fire place hearths)
- Very often 6-sided ("Tomette"), at least one found in Louisbourg.
- Some square ones found in Louisbourg.
(C) Mortar - usually one part lime to three parts sand, which is a good mortar with good quality ingredients.
Problems in Louisbourg: All too rapid deterioration due to:
- Possibly bad or uneven quality of water, sand & lime used.
- improperly washed beach sand- Slow drying sometimes made it subject to freezing. and resulting Cracking, spalling, etc.
- Probably poor workmanship as well.
(3) TIMBER
(A) Basic structural material since dawn of civilization. Techniques evolved from use and nature of material.
By early 18th century: Decadence was evident due to:
- Reduced quantity available- Advent of nail & other means of holding together.
Traditional joinery based on wood itself working in all directions possible; i.e. all except one: direction of entry.
Basic Joint - for pressure stress: Mortise & Tenon.: piece of wood into another (Tenon Into Mortise) held in by a Peg in cross-wise to main direction of stress.
Purpose of a Joint: prevent wood pieces from separating, while allowing some slight movement to accommodate shrinkage, wind pressure, etc. Possibility of dismounting.
Basic Joint for Tension Stress:
- Dove-Tail - tension makes joint, tighter.
Conditions not always ideal
Combinations of 2 basic joints often necessary.Leading to very elaborate joints found in Middle Ages.
Ex. Roof of bakery building.
(B) Louisbourg Adaptation
- Local conditions: climate, materials, etc.
(1) Piquet Construction: stakes close together in a row
- No still visible precedents in Europe except stave buildings in Scandinavia churches - often vertical planking
Very few in Great Britain: Half-logs in ground: may be a development of basic post in ground technique.
- Return to a primitive method: palisade with a roof,
- possible Indian influence (tilt huts in Newfoundland)
Theory for construction
Very word "Piquet" in this sense seems to be particular to Louisbourg - hardly used anywhere else. "Pieu" used in other places.
Normal meaning: a pointed stake, usually-small.
Most very early buildings
- rapidity
- material available
- Techniques: 2 basic ones
(1) Stakes stuck in the ground sometimes in a trench, points sometimes charred.
- A few archaeological remains - enough to indicate technique at ground level, more often just soil discoloration
(2). Logs standing on a sill on ground, then "piquet'.' is a misnomer, but word remained. - much evidence of this - not good building, subject to rotting.
Wall treatment - influence of half-timber or "colombage" (see below) construction: No "Torchis": in Louisbourg smaller spaces between logs filled with moss, clay, mortar, etc. Props at corners.
Roof - Sometimes sod or boards, but more often shingles
(2) Timber Frame Construction - called "Charpente" in Louisbourg documents, since it consisted mostly of main structural members. When there are bracing pieces making patterns, which vary in different regions, it is called "pan de bois,"
(A) Walls- Verticals usually spaced at 4'-0" or more: this.. technique is not not often found in France except in South-West where many of fishermen came from.(B) Floors- In Normandie: closely spaced up-rights ("Colombage") with fill of: "torchis" (wattle and daub), brick or small rubble with coating. In Quebec word "colombage" now applied to studding.
- Adaptation to Local Conditions: wood field stone being most available materials - limited bracing.
- Very ancient technique:
- Sometimes reveted with:- lightness
- inferior materials- Sometimes "piquet fill", not found in France.- mortar with or without lath ("crépi")
- boards, most often laid horizontally, chamfered over lap ("a sifflet")
- Usually long joists full width of building (in Louisbourg sources)- Previous usage: beams & smaller joists closely spaced by width of joist ("tant plein que vide")
- Change occurred around 1700 - to accommodate plaster ceilings
- By secondary sources: joists less closely spaced, (but in Louisbourg: more likely 3'-0" or so between)
- Flooring
- Typical
(in France) short boards ("Bardeaux") Laid
length-wise between the joists supporting plaster or mortar under tile, etc. or wooden patterned
Parquet.
- Louisbourg - 2-pouces
plank nearly always used.
Note: Attic
floors
were often made of rough plaster smoothed over with ox blood to harden and
make fire proof, while giving color of tile. No evidence of this in
Louisbourg?
(C)
Roofs - 2 basic systems:
1 -Trussed Rafters
- older
- less braceable
- every 2 feet or so.
-Need for longitudinal bracing brought on the following system.
2. -Main Truss System3. -Louisbourg- spaced at 10 to 12 feet, with purlins between trusses, supporting loose rafters.
-Usually pretty large members due to tile, slate, even lead roofing. (Westminster Abbey lead roof still in existence since original construction (13th-14th century).
(D) Calculations for sizes and spans.- Typical 2 systems used.
- Due to habit and tradition, fairly large pieces are still called for in "Toisés," although shingle roofing is fairly light. i.e. Our roofs are over-designed by present-day standards.
Quite elaborate methods found in Belidor (1729) book:
- Although quite different from ours: based on tests making no differentiation between hardwood (oak or chestnut recommended) and softwood (spruce, fir, pine).- Some quite arbitrary formulas evolved which still work today when checked with modern practice.
- Multiplying "Toises, Pieds & Pouces": unfamiliar methods used are hard to follow today, since their basic operations are taken for granted and often left unexplained.
(E) Members
JOISTS = "SOLIVES": more or less closely spaced members supported on
BEAMS = "POUTRES": widely spaced large horizontal members braced into walls orPOSTS = "POTEAUX": vertical structural members., (not "vertical beams" nor "poutres verticales" which are misnomers)
RAFTERS = "CHEVRONS": fairly closely spaced small roof members bearing on
PURLINS = "PANNES": widely spaced horizontal members, held on
PRINCIPAL RAFTERS = "ARBALETRIERS": large- sloping member of the
TRUSS = "FERME": main roof frame held together by bracing. ("contreventement") into
TIE-BEAM = "ENTRAIT" which in turn carries the joists of the attic floor.
(4) ROOFING
1. Slate & Tile
No tile in Louisbourg.Very old roofing materials, most common in France, then and now.
Tile is older- easier to produce
- (clay) various forms evolved
Slate
- Expensive: only use in Louisbourg is for King's buildings, But as a matter of course, (very common in France) Not known in ancient times.Fine Technique:
Ridges:
overlapping ridge course ("Lignolet") common today in France.Hips:with sometimes elaborate cutting, for decoration.
but with water infiltration problems.
gradual slanting of pieces toward Hip Ridges:2. ThatchN.B Water penetration at ridges was a recurring problem
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common in Middle Ages, exceptional to-day.3. LeadVery-dangerous fire.
Highly developed techniques.
None in Louisbourg, although Bark & Sod were sometimes used.
- None in Louisbourg (except for flashing)4. Shingles- Used in cathedrals, etc.
- Very heavy
- Long lasting Westminster Cathedral's medieval lead roofing still in place.
- Reason why roof structures are traditionally so strong (Tile also heavy)
- Most common roofing material in Louisbourg.(5) METAL- Slate technique: ridges, etc and mortar flashing: presumed
assumption from tradition & 19th century restorations.
- Exceptional in France. except in mountain areas, where horizontal log construction is common. Varied sizes and names: "Tavaillons" for long ones used in mountain areas.
None used structurally except as ties or crampons, etc. as structural aids.Mostly used as "Serrurerie" (=lock-making) but the meaning of the term is extended to include hardware in general, including ornamental work:
Very much in vogue In 17th and 18th centuries.- gates
- stair-rails, etc.
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Details
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Door & Window Hardware
- From Renaissance times & even Middle Ages:Very elaborate locks - several turns
Highly decorated keys and plates.
More sophisticated approaches were developing during this period.
"Espagnolette""Crémone" - 2 bolts, top one hooked, bottom one joined to it by a bar with a button' so that both can be engaged or disengaged in one movement.- still visible in France- first described in 1738
- pivoting hooked bolt for windows
Turning knobs associated with latches No knobs associated with locks - at least by early 18th century.
(6) GLASS
- Interesting changes in progress in this period:- In Middle Ages: Windows made to admit light more often by means of:
- oiled paper- Stained glass windows all the more extraordinary for Middle Ages.-parchment
- skins (still used occasionally in 18th century)
- 17th Century
- gradual change from small pieces set in lead cames, patterned in panels, set in wood frames, to panes set in wood frames as today.- Windows:Casements (single or double) have always been most common in France. Occasional double-hung ("à guillotine") but quite different detailing:- Late 17th & Early 18th Century- Some use of double-hung window. (Some in Louisbourg ("Toisés")- Method - came from England (originating possibly in Holland) where it kept on being used nearly all the time.
Peculiar sliding techniques:
English way: -Sash slides in a groove the width of the sash.. -N.E. Canada, etc.Fixing of GlassFrench way:-Sash is grooved and slides over a tongue in the frame. (Laperelle H.)
- Points & glued strips of paper very often mentioned in French sources,- Very interesting, but mystifying, as to actual application and materials used.
- Putty used only gradually after late 1720s.
- First mentioned (French sources) in 1710; However mentioned in 1729 as a new invention. (Used in New England and England: in 1701).
- Blondel
-1750-70 Still mentions points and paper as typical. - Very little mention of "mastic" (putty) in Louisbourg (1737 and post 1745)- Some evidence of class set in lead cames found in Louisbourg.
(7) HEATING AND COOKING FACILITIES
Fireplaces, most common for heating and cooking, and this is reflected in Louisbourg.Kitchen Fireplace and Ovens- "Potager" seems to be a 17th century invention: masonry table with grilled openings 'for slow cooking over glowing embers: (Not quite the modern-day barbecue). First called "fourneau potager".
- New ideas starting in this period or before:
i.e. Hot air circulation around metal fire box (metal plates) proposed in 1620s (100 years before Louisbourg), but did not seem to take, even in France. Fire-back common with adjoining room for more efficient use of heat
- But it is only in 2nd half of century that real improvements took shape - provoked possibly by Ben. Franklin's fertile mind.
Stoves: various forms of closed fires had been in use for some time in colder parts of Europe and 18th century saw this evolve into iron and even "faience" stoves of very fine design. (See note below).
- No change till 2nd half of century.Cranes- Pot hangers - Ratchet Hooks ("cremaillère") very common since Middle Ages.
- very little evidence before 19th century (in France). Some wooden ones in Quebec and France in 19th century.(9) Some DIFFERENCES OF CONSTRUCTION in fairly rapid adaptation to local conditions, or perhaps the influence of acadian building practices:- pivoted just outside fire-place - (may be a clue to lack of evidence found for cranes in Louisbourg).
- some used in reconstruction for safety reasons.
Note: Stoves in Louisbourg: - Brick stoves for additional heating are most often mentioned in Louisbourg, but descriptions are scanty, and there is still much left to conjecture as to their actual design. From the size of plates and number of bricks mentioned, they were rather small. N.B. - There is no evidence of use as kitchen stoves, except for the lack of evidence of fire place in kitchen of La Perelle House, would this mean that mean a brick cooking stove? Something like the one tentatively designed.
- Some mention of iron stoves.
(1) The "PIQUET" building: literally "stakes"either driven into the ground or framed into ground plates, chinked with a mixture of clay and moss, or plain mortar, roofed with sods, slabs or boards. Unknown or long since- forgotten in France this type of construction, found in America to a limited extent, seems to have been well known and used by the French arriving from Newfoundland. It was used for the first wave of presumably temporary buildings, some of which lasted fairly well, often as outbuildings.
(2) The"CHARPENTE" type (half-timber) was not quite the «pan-de-bois» nor the "colombage" as known in France, the posts being in general of larger size and usually fairly regularly spaced (around 4"pieds" = 1.30 m = 4' - 3" or so). The fill was not, as often in France, "torchis" (wattle and daub) but rather "piquets", horizontal or vertical, rubble or even brick as sometimes in France. Revetments were either mortar coating ("enduit") with sometimes the stone partly visible, as in France, but perhaps more often, just boarding or planking overlapping "à sifflet" (beveled). Sometimes, in the case of planking, there was no in-fill, which was "less costly and brought the same returns".(3) STONE houses were much less common than in France. The local stone available was generally of poor quality and subject to many problems mainly due to the frost action on the mortar (lime and sand also of poor quality) even though the amply buttered jointing ("crépissage à pierre apparente") covered a good part of the stone surface.
(4) ROOFING for houses was normally wood shingles, nailed on edge-to-edge bevel boarding, whereas in France shingles were used mostly on out-buildings (except in mountain areas) and nailed on spaced lath.
(5) FLOORS in Louisbourg houses were always made of planking, sometimes «tongue and groove», on long joists bearing on exterior walls, spaced 2 or 3 "pieds" (0.65 to 0.96 = 2'- 1-1/4 to 3'- 2"), whereas in France the more common and heavier tile or parquet flooring required beams, spaced at 12 feet or so, supporting smaller and more closely spaced joists. 16
(6) PARTITIONS were nearly always "t & g" boarding or planking and non-bearing, due to the wall-to-wall joists, which had the advantage of providing a freer space and therefore modifiable interior. In France partitions were normally plastered or paneled "colombage", the origin of our present-day studding.
(7) PAINT remained a problem in Louisbourg and the lack of it is often mentioned; the usual pigments, red and yellow ochre and a few others, were available but in insufficient quantities, so that they had to make do with lime whitewash or, to protect the wood revetments, oil which had a blackening effect on the weathering, whence the rather dull aspect of the town even today.
