Coal Tar Pitch Roofing Handbook - 1896 - Pages 40 and 41
IN mills where a wooden floor is required, resting on the earth, the wooden floors are protected from dampness and decay, rats and vermin are excluded and a firm foundation for machinery afforded by the following method.
After the ground has been properly graded and settled, spread a concrete consisting of 20 gallons of hot Coal Tar to each cubic yard of cinders thoroughly mixed and spread over the surface to a depth of 5 to 7 inches, and rolled or tamped to the required grade, over which may be laid without sleepers 2 to 4-inch plank, over which is laid at right angles or diagonally, the wearing floor firmly nailed to the plank below. It is the custom of some builders to bed sleepers in the Tar Concrete on which to nail the first course of plank, while others apparently obtain as good results by omitting the sleepers. The raw Coal Tar thus used contains its normal quantity of creosote oils, the standard material for preserving timber. With advanced mill engineers, this method of constructing wooden mill floors on the earth is considered standard.
While the bulk of this Concrete is usually of the proportions of tar and cinders mentioned, the top inch is frequently made of sand and tar, which make a somewhat firmer concrete, and grades more satisfactorily than the cinders.
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WHILE we have intended herein to cover in a general way all the chief uses of Tarred Felt and Coal Tar Pitch, in building construction, according to up-to-date methods (exclusive of the use of Ready or Prepared Roofings and building papers, as a separate department of the Company) we invite criticism as to omissions and hold ourselves ready to furnish any additional information on the subject to the interested reader.
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