As to the extent, number, and situation of terraces, this point is determined by the conditions of the house and site. Terraces come naturally if the house be on an eminence, but even in cases where the ground recedes only to a slight extent, the surface of a second terrace may be lowered by increasing the fall of the slope till sufficient earth is provided for the requisite filling. The surplus earth dug out in forming the foundations and cellars of the house, or rubbish from an old building, will help to make up the terrace levels and save the cost of wheeling and carting the rubbish away.
Like all embankments, terrace walls are built with "battered" fronts or outward slope; the back of the wall will be left rough, and well drained. A backing of sods, Mr Milner says, will prevent thrust, and admit of a lessened thickness in the wall. The walls should not be less than three feet in height from the ground-level beneath, exclusive of the balustrade, which is another three feet high.
PLAN OF TENNIS LAWN, TERRACES, AND FLOWER GARDEN.
The length of the terrace adds importance to the house, and in small gardens, where the kitchen-garden occupies one side of the flower-garden, the terrace may with advantage be carried to the full extent of the ground, and the kitchen-garden separated by a hedge and shrubs; and at the upper end of the kitchen-garden may be a narrow garden, geometrical, rock, or other garden, set next the terrace wall.
The treatment of the upper terrace should be strictly architectural. If the terrace be wide, raised beds with stone edging, set on the inner side of the terrace, say alternately long beds with dwarf flowering shrubs or hydrangeas, and circles with standard hollies, or marble statues on pedestals, that shall alternate with pyramidal golden yews, have a good effect, the terrace terminating with an arbour or stone Pavilion. Modern taste, however, even if it condescend so far as to allow of a terrace, is content with its grass plot and gravel walks, which is not carrying Art very far.
Laneham tells of the old pleasaunce at Kenilworth, that it had a terrace 10 ft. high and 12 ft. wide on the garden side, in which were set at intervals obelisks and spheres and white bears, "all of stone, upon their curious bases," and at each end an arbour; the garden-plot was below this, and had its fair alleys, or grass, or gravel.