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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


Draft of a Memo on Masonry Finish

by [Linda Hoad]

In Historical Memoranda Series, 1995,
Unpublished Report H F 25 1995
(Fortress of Louisbourg c. 1972)
[Linda Hoad, "Interior Finish,"
In Historians,
Preliminary Architectural Studies,
Volume 03, Unpublished Report HG 02
(Fortress of Louisbourg, 1972)],
Report Number HF 25 1995 02)

This report will compliment the outline of masonry finishing given in the Chateau St. Louis Historical Report Series I. The first part deals with the relative types of masonry finishes and the second deals with recording their use in the King's Bastion barracks.


The initial specifications of 1718 list the materials to be used in masonry works at Louisbourg. The first is plaster, which is to be drawn from various areas on the Island and to be used on chimneys above the roof and on partitions. The second item mentioned is lime, which again has to be taken from the best limestone found on the Island and to be well baked. It was to be used in a 1:2 ratio and so mixed that one ingredient could not be separated from the other. Mortar for works in water would be made with lime powder which had been burned. The third item mentioned is "Ciment". This is to be used for important work and would consist of powdered old tiles or new burnt tiles passed through a sieve and then mixed with an equal amount of quick lime and whatever water would be necessary. It also was to be well mixed so that neither element could be distinguishable. "Ciment" has come down to modern usage and is directly translatable as cement but in the 18th century it seems to have had the function of a good binding agent.

Ganet's contract of 1726, vol. 8, f. 164, gives us four masonry finishing substances - "crépisage à pierre veu", "crépisage foité oû rustique", "crépisage foité oû rustique et enduit et polie par dessus", and finally "crépisage en platre enduit et poli".

The first, "crépisage à pierre veu", is what we have come, to know as "crépisage à pierre apparente". The second, "crépisage foité oû rustique" seemed to be essentially the same as above only with a roughed coat on the exterior, and is what we would consider modern pointing. [I can find no adequate definition for rustique, but I do not agree with this explanation. L.H. 1971.] The third employes the finish of the second with an added "enduit et poli" on top. This would seem to be a basic masonry coat with another lime coat on top which had been well finished. The last one, "crépisage en platre enduit et poli", would seem to be a plaster second coat which had been well finished.

There are two additional items which are of interest in this particular contract. The first concerns whitewash which is reported done in three coats. The second is the use of brick and tile "ciment" used in arches and other areas thus accounting for the fact that much of the masonry remains on some of the casemates to the present day.

We next encounter the masonry finishes in the 17Z7 Toisé which lists three types: "crépis à pierre aparente"; "crepi et enduits en mortier"; "enduits en Platre". The prices awarded for this work did not correspond with the prices given in the 1726 contract.

A supplement to Ganet's contract of October 1727 returns to three types of masonry finish. The first, "crépis à pierre aparente", has specified that a 1:2 ratio of mortar and sand be used, the sand having been put out for 6 months before use to try and extract all the salt from it. Next we have the "enduit" which would be placed on top and which would have been previously passed over a skuttler [?] to avoid lumps. Finally, we are given the "enduit en platre". Also dealt with in this particular contract is whitewash which, in this case, is done in two coats.

A Marché of 1737 gives us the same three usages of masonry finishes, These are: "crépissage à pierre apparante"; "enduits en mortier ordinaire"; "enduits en platre". There is little change here, as the first item contains elaboration on how the work is to be done. The masonry over which the new masonry is to be applied is to be cleaned and wetted beforehand. The final is to be applied as soon as the plaster has been baked. As well, whitewash is mentioned in two coats.

The final contract which deals with masonry finishes is the Surlaville contract of 1753. It describes the three basic finishes as we have outlined before. With regard to the whitewash, two coats are to be used but the final coat is to have glue placed in it to make it more durable.

Although we begin with four separate finishing substances, the evolution is clearly to three types of masonry finish. The one which seems to have been eliminated, crépissage rustique, would have left a pointed finish. However, I suspect that the ordinary crépissage done with the stone showing was rough enough so that a second masonry coat could be easily applied with good bonding resulting. Hence, the pointed finish was not necessary. [Again, I disagree, but can offer no alternative explanation.)


The following are locations in the King's Bastion barracks for which evidence has come to light concerning the application of the various finish coats:


(a) Officer's rooms and guard rooms

(b) Central Passage

(c) Governor's Rooms; (d) Chimneys - Governor's wing, Officer's rooms and Corps de Guarde

(e) Sale d'armes

(f) Two in Intendant's Wing

(g) Recommended for Soldiers' rooms


(a) Chapel

(b) Lunettes

(c) Big rooms (gable-end)

(d) Governor's rooms

(e) Officer's room

(f) Tableaus (lintel and jamb)

(i) 54 for window

(ii) 6 for doors Chimneys - 24

(g) Clock


(1) Exterior walls of Barracks

(2) One side of Place of Arms

(3) Soldiers' rooms.