186 



VETERINARY HYGIENE 



additional precaution may be taken by coating the whole outer 

 surface of the wall up to and about 6 inches above the ground level 

 with Portland cement plaster, pre- 

 ferably treated with a good water- 

 proofing liquid, or, alternately, 

 the same surface may be covered 

 with vertical asphalt, although 

 such work is not worth executing 

 unless the material used is mineral 

 rock asphalt, and this method is 

 probably too expensive. 



A method which may be 



FIG. 86. Section through a 

 wall adjoining high 

 ground with a dry area 

 covered and ventilated. 



FIG. 87. Section of a re- 

 taining wall with cement 

 or rock asphalt vertical 

 course and asphalt 

 damp - proof course. 

 Note the field drain 

 covered by dry stone 

 infilling. 



adopted for new retaining walls is to 

 build the wall hollow, particularly in the 

 case of brick walls, and to form an 

 outside dry area as wide as possible 

 by building the actual retaining wall 

 clear of the building. The bottom of 

 this area should have a properly con- 

 structed cement or tile channel, which 

 must be below the floor level and damp 

 course level, having proper outlets for 

 any water which may gather, the out- 

 lets being arranged in such a way that chokage is impossible. 

 Such dry areas must be covered over at the top and properly 



FIG. 88. Type of retaining 

 wall for a building with 

 very high adjoining 

 ground. The damp - 

 proof course is carried 

 under all the floor and 

 jointed carefully to the 

 vertical asphalt. 



