Building a Terrace
Terraces present wonderful possibilities in the garden. They are outdoor living rooms during good weather and form a transition from the outdoors to the indoors through-out the year. The terrace may be either at ground level, below ground level, or raised above it. In another article we will talk more about the above ground and sunken terrace.
The simplest type is ground level, which requires only the grading we have indicated below. There is a wide choice of flooring materials to use. One may use cement, poured and leveled with a large board. Smooth turf may be used, in maintaining the drainage grade or including shallow drainage paths, in which case the preparation will be the same as for other lawn areas and various other types of bases.
The use of flagstones is made simple by applying a load of sand or gravel to the subsoil and digging the flagstones into the sand or gravel. The niches between the stones can be dug out and filled with topsoil and grass or other cover (mosses, creeping thyme, etc.) planted between them. This gives a very pleasing effect.
Another idea is that hollow clay building tiles can be split and laid as units in the terrace floor, their rough edges in the soil.
Another good surfacing material is “exposed aggregate,” which is free from glare because of its rough finish. For this type of surface, build a form of 2 x 4′s. Pour the flooring in squares, one square at a time, and level with a straight board. The material used is concrete of from which the top layer of cement is washed to expose the pebbles that make up the concrete. If you wish, a mixture of cement, sharp sand and crushed rock or pebbles can be mixed so you are able to pick the type of stone or pebble you wish to expose.
If you are able to find them, redwood or cypress blocks may also be used for terrace floors and are very attractive, although somewhat less durable than stone or brick. You can buy the blocks cut to size and lay them directly in a bed of sand, which in turn has been laid on compacted gravel.
Unmortared brick, laid in a pattern, on 2 to 4 inches of well-tamped sand, with loose sand in the crevices for grass, makes a hardy and simple-to-construct terrace floor. The bricks may be laid flat or on end, and to keep them from spreading, drive an angle iron against the corners. Use a pattern that follows the lines of your terrace.
Grading for Terraces
In leveling an area for a terrace, there is no need to insert subsoil drainage. Save the topsoil. For almost all terraces, it is a good idea to tamp the soil, and even to pour a quantity of gravel cinder or crushed rock as a base. Terraces require a level area as a rule, but the grade sloping away from the house should be maintained.