 Curbs
are usually formed of natural stone, although concrete curb,
usually combined concrete curb and gutter, are increasing
very rapidly in recent years—partly because of the decrease
in the price of Portland cement. Granite is the best natural
stone, but it is usually very expensive. Limestone and
sandstone are frequently used, but they are generally too
easily chipped or broken. Concrete, unless made with unusual
care or protected by steel on the edge, is too friable for a
business street where heavy loads frequently back up against
the curb.
They are 4 to 8 inches thick, usually 4 to 6 inches,
depending upon the quality of the stone and the locality.
The depth must be sufficient to prevent the thrust of the
earth behind the curb from overturning it, and is usually 18
to 24 inches. If the section are to short, it is difficult
to keep them in place and the general appearance is not
good; and if they are too long, it is difficult to handle
and set them, and nearly impossible to get a firm bearing on
the bottom. They usually vary from 3 to 8 feet.
Curbs help to define your garden, patio and driveways;
they can be matched with pavers for a uniform look. The main
aim of landscaping to create a smooth transition from the
outdoors to the indoors and curbs help them do the same.
Curbstones are used for roads, driveways, parking lots and
many other landscape construction applications.
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