CONSTRUCTION NOTES 263 



cushion without a concrete base the bricks may be laid directly on the 

 foundation of natural sand after the sand has been thoroughly wet and 

 tamped or rolled. 



(ad) Tile walks on concrete foundation (foundation course and wearing 

 surface}. Tile walks are usually constructed in locations where refinement 

 of grade and permanence of surface are required. For this reason such 

 walks are built as solidly as possible and without any sand cushion between 

 the bottom of the tile and the top of the concrete base. A foundation course 

 of cinders is put in place in the same manner as for brick walks, allowing 

 the proper depth to provide for the thickness of the tile and bed of mortar 

 under the tile (see figure 3, Plate no). The depth of cinders at the side of 

 the walk should be six inches, the depth of concrete four inches (1:3:5 

 mixture), and the depth of mortar one inch (1:2 mixture), well moistened 

 but not thoroughly wet. On this mortar surface the tile are carefully laid 

 to the desired pattern and grade. Neat cement is then brushed into the 

 joints between the tile, and the entire surface of the tile walk is sprayed 

 carefully with water. Any trace of cement on the tile may be removed 

 with a diluted solution of muriatic acid (not over one pint of acid to each 

 gallon of water) after the cement has set for a period of three or four hours. 



(ae) Concrete walks (foundation course and wearing surface). The 

 foundation course of cinders is installed as outlined under \aa. On the 

 surface of the cinders a layer of concrete four inches in thickness (1:3:5 

 mixture) is put in place and is then finished with a smooth trowelled surface 

 or with a wood float. If the concrete walk is to be subjected to intensive 

 traffic then this concrete course should be constructed in two layers, both 

 of which must be completed during the same day. The bottom layer of 

 concrete three inches in depth (1:3:5 mixture) should be placed and the 

 wearing surface of one-inch depth (1:3 mixture) should be applied within 

 a period ranging from four to six hours after the bottom course of concrete 

 has been finished (see figure 4, Plate no). 



Forms are necessary for construction of concrete walks. These forms, 

 usually two by four inches, are securely staked on required lines and grades. 

 Cross strips are placed at four or six-foot intervals. Sometimes every other 

 section is constructed, the cross pieces removed, and tar paper is then put 

 in place for the joints, extending the entire depth of the concrete. 



Surface colors of concrete walks may be varied by the use of lamp- 

 black (to darken the walk) ; copper filings (to obtain brown tone) ; hematite 

 (to obtain reddish brown). These substances are mixed with the surface 

 layer only. Concrete walks should not be used for a period of 48 hours 

 after completion. During early spring and late fall, walks should not be 

 used for a period of four days after completion. Newly finished concrete 



