Near View of Shelter.
Steps lead downwards where the wall of the smoke-house has been removed.
Roof.—In any type of smoke-house, the roof should fit tightly at the eaves, and the only vent should be in or near the roof-ridge.
In an ordinary smoke-house, the opening should take the form either of a low jack-roof or of squat chimneys protected against rain. If a jack-roof is chosen, it may be so low as to need no scheme of adjustment, or otherwise adjustable swing shutters must be provided. The chimneys may be made with such low fitting between the cap and the body that no interior swinging flaps are required.
During the operation of smoke-curing the smoke vents must remain open to a degree which is arrived at by experience. Failure to provide a comparatively free egress for smoke and moisture will bring trouble in its train. After a house has been in use for some time, it will be noted that the timber becomes covered with a shiny tarry coating deposited by the smoke. If the rubber remained in the house for an equal period, it would take on the same appearance. During the interval between the entry and the exit of the rubber some amount of deposit does take place, and it is this mixture of creosotic substances which plays a part in fitting the rubber to withstand growths of mildew which would otherwise form.
If proper smoke-vents are not provided, the moisture evaporating from the sheets is unable to escape quickly enough, with the result that a great deal condenses at night-time upon the inner surface of the comparatively cool roof, and falls back upon the rubber in unsightly black “drips,” which leave a distinct mark on the sheet. Even if vents are open, this may happen during seasons of rain. The temperature of the moist smoke in the roof-ridge may be as high as 130° to 140° F., while the outer atmosphere may have been cooled by rain to 70° F. Such a difference on the two surfaces of the roof must lead to condensation within the house, with consequent “dripping.” It used to be the custom to drape sacking material above the bays of racks in order to prevent the drops of liquid falling upon the rubber; but often for want of renewal the last state was worse than the first. Modern houses have often an inner lining, a few inches below the roof. This is made of soft wood which receives any product of condensation and absorbs it.
Other Types of Smoke-House.—So far we have confined the arguments to smoke-houses of the usual type. There are others which vary in either design and method of working, or in the material of the structure. Mention may be made of the most prominent of these.
Brick Houses.—Some houses are constructed of brick, and may have one or two storeys above the furnace chamber. The floors are sometimes made of ferro-concrete, and the furnaces may also be of this material. These brick houses give satisfaction, but there would seem to be some difficulty in obtaining and maintaining the desired temperature, although it is not quite plain why this should be so. The principle of these buildings is the same as that of the ordinary iron house, and the suggestions made in previous paragraphs apply with equal force.
“Third Mile” Type.—Reference has been made to the “Third Mile” type of furnace. This is an integral part of a smoke-house, which for clearness of distinction may be known as the “Third Mile” type of smoke-house, the original of which was erected on the Third Mile Estate, Seremban, F.M.S.