80 Modern Fireproof and Watertight Building Materials, 



against the sides. The continuity of the covering is effected 

 by securing strips of the same material over these divisions 

 in the manner indicated, and finally the whole is treated with 

 asphalt in a fluid state. 



A quite modern construction is the wood-cement roof. 

 The purlins have only a slope of 1 foot to 25 feet ; they are 

 covered with boards well-tongued and grooved. Over the 

 boards is sieved sand J-inch thick, then follow three layers 

 of paper. This is a sample piece, each layer brushed carefully 

 with fluid asphalt. After this being done, the whole area of 

 roof is filled in, 6, 12, and more inches, with coarse gravel and 

 good soil on top. 



Fig. 11. — Here are given delineations of the various 

 roofs in vogue — brick roof, slate roof, corrugated-iron roof, 

 and stone-paper roof. You will observe that, apart from the 

 moderate cost of the latter, a considerable further saving is 

 effected on account of the low pitch which this material 

 renders possible. 



Fig. 12 shows the stone-paper roof as adapted to sheds. 

 Should exception be taken to its dark colour, I may mention 

 that this might be varied to any extent by treating with 

 ordinary lime-wash. 



Fig. 13 represents the so-called wood-cement roof, 

 applied to private residences and to warehouses. In the 

 former it permits of a perfectly flat roof, which can be utilised 

 as a flower garden, whereby the charms of the hanging 

 gardens of Semiramis, so celebrated in ancient history, may 

 be enjoyed at the present day; also, and especially in the 

 latter case, the entire enclosed space is available for the 

 storage of goods and for other rooms. That these rooms are 

 fireproof, with regard to fire in the neighbourhood, is to be 

 taken for granted. If, instead of wooden joists and boards, 

 iron girders on curved corrugated iron be employed, as has 

 been done for the roofs of the Imperial Printery in Berlin, 

 this kind of roof may be considered absolutely fireproof. 



The asphalt felt has its origin in England. It is produced 

 from cotton and other textile waste with an admixture of 

 pitch in a fluid state. It has not proved particularly suc- 

 cessful, and its application seems to be limited to the 

 securing of ridges and for the preliminary coverings of 

 roofs. 



Asphalt plates consist of layers of asphalt alternated with 

 laminse of some coarse fibrous materials. This combination 

 was known to the ancient Egyptians and Babylonians. It 



