Climate and Health in Hot Countries and the Outlines of Tropical Climatology / A Popular Treatise on Personal Hygiene in the Hotter Parts of the World, and on the Climates That Will Be Met Within Them.

by George Michael James Giles

The roofing materials generally employed in tropical countries are thatch, tiling, terraced constructions, and corrugated iron. Thatch is, from many points of view, an excellent material, as while it favours ventilation by being extremely pervious to air, it gives excellent shelter from rain, and is quite unequalled as a protection against the sun; in addition to which it does not, to any appreciable extent, throw out into the house during the night the heat absorbed during the day.

With all this, it has great and, it is to be feared, preponderating disadvantages, the principal of which is that it forms a perfectly ideal refuge for vermin of all sorts, vertebrate and invertebrate. As a rule, owing to the high pitch necessary in this form of roofing, the lower edge of the roof is rarely more than a few feet from the ground, and owing to the usual existence of creepers, trellises and similar facilities, is usually easily accessible to any animal endowed with the most moderate powers of climbing. Owing to this, such roofs are usually honeycombed with the nests of squirrels, rats, civet cats, and half wild domestic cats, to say nothing of snakes, and birds and other flying things. The large empty space between the ceilings and the rafters is usually alive with bats, and as all this extensive population is quite without any system of conservancy, an old thatched roof is simply permeated with guano; and the emanations from this necessarily find their way into the house, and indeed are always plainly perceptible in a thatched house that, for any reason, has been shut up for any length of time.

Besides this, the substance of the thatching is always slowly decomposing under the slow action of mildew, and this adds further musty exhalations to the bouquet. Hence, if used at all, the thatch should be completely renewed at frequent intervals, and its employment should be confined to situations which cannot be scaled by large vertebrate vermin.

Where it is used, the interior of the rooms should be completely cut off from the cavity of the roof by some fairly impervious ceiling, such as one formed of match-boarding, and not, as is commonly the case, by a “ceiling cloth” of ill-stretched canvas.

These “ceiling cloths” are utter abominations, and, even when their untidy appearance is ameliorated by subdividing the cloth into a number of small panels, the improvement is purely one of appearance, and in no way diminishes their sanitary defects, so that no effort should be spared to induce landlords to replace them with match-boarding or any material that will shut out the emanations from the thatch and its inhabitants.

For some reason, the lath-and-plaster ceilings and partitions, so commonly used in Europe, are never employed in Indian house-building. It is difficult to understand why this is so, as the natives are skilful plasterers, and there would be no difficulty whatever in teaching them this particular application of their trade, which would be a valuable and inexpensive expedient in this and a number of other cases.

Tiles of the old-fashioned sort present few of the advantages of thatch, and most of its disadvantages, besides numerous special objections of their own, but these remarks do not apply to roofs formed of large tiles of European patterns laid on a properly graded framework of squared battens. To these latter the only objection is that they let in too much heat unless they are supplemented with a tolerably substantial ceiling; and the same remarks apply even more to corrugated iron, but both these materials, and especially tiles, are excellent materials for verandahs, especially those of upper stories, where weight is a consideration.

Corrugated iron, however, is scarcely tolerable in extreme climates unless it is actually doubled, and the most scientific way of doing this is to form a ceiling of corrugated iron of a thin gauge screwed up to light joists and painted white below. On the upper surface, should be spread about an inch of dry sand, to retain which it is necessary that any ventilation openings should be protected with a wooden edging. The outer roof should be of stouter gauge, and must of course be pitched at an appropriate slope, and it is of the first importance that the space between the two roofs should be freely ventilated by large openings placed at the apices of the gables, but these openings should be secured against the entry of birds and cats by means of wire netting, and all other openings by which they can enter should be carefully closed with plaster. The coolness of a roof so planned depends largely on the thickness of the layer of dry sand, and, provided the joists that carry the sheets are fairly strong, there is no difficulty in raising this to even a couple of inches. The preceding materials all have the disadvantage that they must be pitched at a considerable slope, and hence cannot be used as a platform for sleeping on.

All considered, however, a terraced roof, formed of brick arches supported on steel girders, covered with concrete, is by far the best for most tropical climates. It forms an excellent protection against sun and rain, and the smooth finish of both its upper and lower surfaces offers absolutely no hiding place for even insects; besides which it forms an excellent elevated platform on which to sleep during periods of intense dry heat. Its one disadvantage is that a great deal of the heat absorbed during the day is radiated into the rooms at night, and that it generally is inferior as a non-conductor either to thatch, or to double roofs of any description.

Another form of terraced roof commonly found in dry climates consists of a considerable thickness of beaten clay, spread on mats supported on a system of beams and battens.