262 PARKS 



mortar (1:3 mixture) in accordance with the desired pattern, care being 

 taken not to get mortar on the surface of the brick. When these bricks thus 

 placed have had a sufficient time for the mortar to set, clear cement if the 

 joints are small (y inch or less), or a dry mixture of cement and sand (1:2) 

 if the joints are larger, is swept into the joints and the walk is then sprayed 

 carefully in order thoroughly to wet the cement in the joints. With joints 

 larger than one-fourth inch it is best to pour a very wet grout (i : 2 mixture) 

 carefully into the joints until they are rilled. On certain types of brick 

 with other than a very smooth surface it is extremely difficult to remove 

 the surplus cement, which may permanently mar the surface of the finished 

 walk. Brick surfaces are brought to an even grade by laying a board on the 

 surface of the walk and tamping on the top of the board before grouting the 

 joints and before the mortar in which the brick are placed has set. If brick 

 walks are constructed with a herringbone pattern (figure i, Plate 112) it 

 is very desirable that the curved portions of such walks should be radial 

 curves; otherwise considerable difficulty will be experienced in adhering to a 

 uniform and economical method for laying the design in actual construction. 



(ab) Brick walks on sand cushion without concrete base (foundation 

 courses and wearing surface). On the subgrade prepared in accordance with 

 previous instructions and at a depth of approximately 14 inches below the 

 finished surface of the brick at the sides of the walk if the brick is to be 

 laid on edge, and 12 inches if the brick is to be laid flat, a foundation course 

 of cinders is put in place in two layers of equal depth, making a total depth 

 of eight inches at the side of the walk. On the surface of these cinders, 

 which have been thoroughly watered and tamped or rolled, is placed a 

 layer of fine sand (passing J/g-inch screen) to a depth approximating between 

 one and two inches when tamped or rolled. Brick are then laid upon this 

 course of sand, firmly put in place and the joints filled with the same fine 

 sand, to which may be added if occasion required ten per cent of dry cement. 

 The entire surface of the walk is carefully flushed and the brick then care- 

 fully tamped, using a board, in order to bring the surface of the walk to the 

 desired finished grade. On all brick walks of this type it is desirable to 

 have a border course of brick as shown in figure i, Plate 112. 



(ac) Brick walks for southern conditions where frost action is a negligible 

 factor. The following variations from the foregoing instructions are adopted 

 in the construction of brick walks under southern conditions. In clay soil 

 the depth of cinder foundation under the concrete base may be reduced to 

 four inches as a minimum depth and the concrete base may be reduced to 

 three inches in thickness. If walks of this type are laid on sand, the cinder 

 foundation may be omitted entirely, and the concrete base made with a 

 thickness of three inches. In the construction of brick walks on a sand 



