CONSTRUCTION NOTES 267 



clay soil where the frost action creates a serious problem. On sandy soils 

 and in the southern climates stepping-stones may be laid directly on the 

 natural soil which has previously been tamped to the required surface 

 grade. 



Terraces. Terrace areas with various types of surfaces present much 

 the same problems as those involved in the construction of walks with 

 similar surfaces. There are a few important points which should be kept 

 thoroughly in mind as contributing largely to the successful construction 

 of terraces. The surface of the subgrade should be so formed that any 

 water reaching it will immediately be carried over it to drainage lines 

 installed at intervals not exceeding ten feet. The surface of any terrace 

 should be very carefully studied so that no surface water will stand on 

 any portion of the terrace without ready access to a drain inlet. Preferably 

 such terraces should slope on a grade of one-fourth inch in each foot of 

 terrace width away from the house. If split flagstone is used in terrace 

 surfacing this flagstone should present a rather even surface, especially if 

 the terrace is to be used freely as an outdoor dining room or living room 

 area. Where a terrace is to be used for such purposes the joints between 

 the stones should either be filled with cement and the terrace constructed 

 on a concrete base, or the joints should be filled with a sandy loam, and 

 be not greater than one-fourth to one-half inch in width in order that the 

 legs of chairs cannot readily slip into these crevices. 



5. Curbs for Walks. 



Where it is desired to construct a curb along either side of any walk 

 this curb should be constructed in a permanent manner in accordance with 

 figures I and 2, Plate in, unless it is not necessary that the curb should 

 maintain permanently the line of the original plan. Curbs for concrete 

 walks may become a part of the concrete foundation and wearing surface, 

 and should preferably be constructed as a single operation in connection 

 with the construction of the walk. Curbs for the sides of brick walks on 

 concrete foundations (see figure I, Plate in) should be constructed by 

 immediately putting the brick curb in place before the surface of the walk 

 is paved with brick. Curbs for any walk, other than a walk surface on a 

 concrete foundation, should be constructed as shown in figure 4, Plate in, 

 in order to be permanent. The depth of the concrete foundation or such 

 curbs should approximate eighteen inches with a concrete mixture of 1:3:5. 



For items of cost data as follows: excavation and trimming to sub- 

 grade; spreading and tamping cinders; concrete foundation; cutting and 

 laying flagging; laying drain tile, see Landscape Construction Notes I, 

 Volume XII, No. 2, January 1922. 



