GRAVEL PATHS 69 



in the construction bf these roads, the crown could be 

 greatly reduced and equally good drainage secured. 



Exterior walks, that is, sidewalks along streets, have no 

 crown, but are raised on the inside to provide drainage 

 toward the gutter. A slope of 1J inches for an 8-foot side- 

 walk is sufficient. 



The foundation of a cement walk consists of 8 inches of 

 cinders. On this is placed 3 inches of concrete and on top 

 of this 1 inch of rich mortar. The foundation is sometimes 

 omitted hi the South and may be occasionally omitted in 

 the North if the walk rests on a bed of dry gravel. (See 

 Fig. 19, page 55.) 



The surface should be divided into blocks to provide 

 for cracks. For an 8-foot walk, there should be a longi- 

 tudinal marking down the middle ,and transverse mark- 

 ings about 4 feet apart. It is not wise to allow a smooth- 

 troweled finish, as then the walk is apt to be slippery. 

 A rough finish is better; but the roller finish is not to be 

 recommended. Little advantage is gamed by the undula- 

 tions in the surface thus made. 



ravel Paths. The crown should be a little higher 

 than for cement walks, say 50 per cent. more. 



The foundation should consist of 6 inches of cinders and 

 the gravel should be 4 inches deep. 



The selection of the gravel is a very important matter. 

 Crushed stone is not to be recommended, but rather a 

 hard rounded gravel with cementitious properties similar 

 to the famous Roa Hook gravel found on the Hudson River. 

 The gravel should of course be screened and should consist 

 of round flat stones, not spheres. Gravel of this character 

 is much easier to walk upon than gravel composed of 

 spherical stones. Gravel is an excellent material for path 

 construction. It is cheaper than cement, brick and asphalt 



