Though the stone, when exposed to air, hardens somewhat, it remains too soft and porous to stand well without protection. When burned it gives an excellent lime, which is used with sand as a mortar in which to set the stone, and as a stucco inside and out to protect from moisture and disintegration, and finally as a whitewash for finish and cleanliness.
Besides the influence on building forms that this stone had, as a universally available and easily worked material, its presence throughout the island had another effect. In spite of abundant rainfall, the stone structure of the island is so porous that there is no natural accumulation of fresh water resulting in an entire absence of springs and streams, so that the inhabitants have been at all times dependent on catching and storing rain water. Thus each roof serves not only its usual protective purpose, but must also serve to catch fresh water. The result is a feature, a marked Bermudian characteristic of roofs immaculate with whitewash and a system of gutters leading to that necessary adjunct of every Bermuda dwelling, "the tank."
The form of roofs employed varies considerably. Roofs with gable end and hipped roofs are both used, sometimes in the same building. There seems to be no generally adopted angle of pitch. One finds roofs almost flat and in different degrees of steepness to the sixty degree pitch of some of the outhouses and butteries. The roof surfaces are never interrupted by dormer windows.
The roof spans are in no cases large, rarely exceeding eighteen feet, probably governed by the limited sizes of the cedar lumber available for floor beams, but in any case apparently quite sufficient for the needs of the inhabitants. This smallness of span forced a smallness of division in plan, and contributed to the general small scale, a characteristic of island architecture referred to elsewhere.
The roof construction consisted of rather light sawn or hewn rafters, either butted at the summit or framed into a ridgepole, and securely fastened to a heavy plate placed on the inside line of the masonry wall. These rafters were tied over interior walls or partitions by long ties at the plate level, but elsewhere by ties placed too high up for structurally efficient service, with consequent thrust at the ends and irregular sagging of rafters. This was done for the purpose of allowing the ceilings of the rooms enclosed to run well up into what otherwise would have been dead roofspace, giving the rooms a surprising height and airiness in spite of low eaves. This form of ceiling, finished either in plaster or wood, gives rise to the not ungraceful, so-called "tray" ceilings, from a fancied resemblance to a serving tray. These, I think, are peculiar to old Bermuda, and Bermudians point them out with pride to visitors.
In the carpentry of many of the roofs, construction details of the shipwright rather than the carpenter prevail. Bermudians of the older days were well known for the excellence of their sloops and smaller sailing vessels, and one sees constantly the introduction of shipbuilding ideas in their houses—cedar knees locking at the angles, the timbers serving as roof plates, and tie-beams with the gentle curve or camber of a deck beam, are not infrequent.
The surface of the roof is constructed of sawn slabs or tiles of Bermuda stone about one and a half inches thick, by some ten inches to a foot in width with a length slightly greater, known locally as "slates." These are fastened to strips of cedar set transversely to the rafters at proper intervals. An occasional slate is slightly raised, to secure necessary ventilation of enclosed roof space. These roof tiles usually overlap in the fashion of slates or shingles in horizontally parallel rows, but sometimes are laid flat with butting edges. The eaves have but a small projection of six to ten inches, and are supported on stubby square sectioned jack-rafters projecting from above the plate line to the edge of the tiling above. With the plate on the inside of the wall, this arrangement gives a shadow at the eave line that is decorative in its varying intensity, without the use of any mouldings whatever. In all likelihood, however, this type of eave, so different from the greatly projecting eaves of other sunny climates, was adopted to prevent the occasional hurricanes from unroofing the houses.[1]
[1] In spite of this a hurricane of unusual violence destroyed many roofs in September, 1922, uprooted hundreds of fine cedars and other trees and did thousands of pounds damage generally.
The whole roof surface is heavily coated with semi-liquid cement, which when it hardens serves to make the roof water-tight and softens the edges and angles to the eye. This, when freshly whitewashed, gives to the roofs the resemblance to "icing on a cake" spoken of by Mark Twain.
From the engineering point of view, the construction of the roofs may not be mechanically scientific, but whatever the deficiencies, the lack of precision and exactness has given to them that delightful quality of accidental irregularity and unevenness that is the despair of architects for new work, and can hardly be obtained by even obvious affectation.