Paving Solutions

Prepared by CSBE Team, 2005

1. Introduction

A most effective manner for achieving beautiful, water-conserving gardens is through combining planted (softscaped) and paved (hardscaped) areas. There are numerous solutions for this incorporation of paved areas - which can include materials such as ceramics, stone, or concrete - within a garden context. One can create planted areas that surround paved surfaces and that include a mixture of both low plants and trees. This composition affords a sense of lush greenery and also provides shade from the hot sun. Another option is to place small green areas within paved surfaces to create an attractive composition of colors and textures resulting from the combination of the plants and the paved surfaces of the garden.

In addition to providing an aesthetic feature that saves water, paved surfaces serve as an efficient water harvesting system. They harness water that can be directed either into a collection tank or to planted areas where the soil would store it for later use. Also, paved areas can serve various utilitarian and recreational purposes that include sitting, playing, or even parking vehicles.

2. General Considerations for the Creation of Paved Areas

It is important when creating a paved area in a garden to choose paving materials that are appropriate for outdoor use. Select materials that resist glare and slippage, and that do not show the accumulation of dust or dirt easily.

Also use materials that tolerate the various elements since outdoor areas are regularly subjected to potentially destructive forces including climatic changes and heavy uses. Generally, it is preferable to use locally available and tested paving materials. These usually are less expensive, and extra supplies can be found relatively easily when the need arises for maintenance or expansion work. Also, the availability of an experienced work force usually is more readily available for local materials.

Other issues that need to be considered include the composition of the bedding that supports the paving surface. Ideally, the bedding should be placed on top of an undisturbed layer of soil. If such a layer is not available, the soil would require compacting. A compacted layer of aggregate then would be placed on top of the soil. A layer of concrete might be needed over the aggregate, and this concrete layer might require reinforcement. The exact composition of the bedding depends on factors such as the type of soil originally located on the site and the type of use intended for the paved area. Obviously, an area intended for parking will need to be sturdier than one used primarily for seating.

3. Paving Materials

A wide variety of paving materials can be used within a garden context. These include the following:

Pre-cast concrete tiles:
Concrete provides a diversity of possibilities as a paving surface. Concrete tiles can be found in various thicknesses that offer different strengths, they come in a variety of shapes and colors, and can be made to resemble other materials such as stone or brick (figure 1). Concrete tile types include those with relatively smooth surfaces, as well as ones with slightly protruding patterns. Another common type of concrete paving tiles is exposed aggregate tiles, which consist of concrete mixed with pebbles, thus providing a somewhat rough texture (figure 2).

Other possibilities include interlocking concrete paving systems, which provide a number of advantages in relation to rectangular or square concrete tiles (figure 3). The interlocking nature of such systems strongly binds individual paving units and prevents any lateral movement in them. Consequently, they do not require mortar to bond the individual paving units to each other. Because mortar is not used, these systems effectively deal with water ponding problems since excess water simply seeps through the joints to settle in the soil below. Also, the strong bonding created between the individual paving units means that these systems do not require a concrete bedding and can be placed directly on a compacted layer of sand. Another advantage of interlocking paving tiles is that they can be removed easily and placed again in the same location (if maintenance work is to be carried out) or used in a different area.

Cast-in-place concrete:
Cast-in-place concrete can be used to provide various patterns and textures (figure 4). This method relieves one of having to transport finished concrete tiles to the site. However, when using such a system, make sure to place contraction joints at adequate intervals to avoid cracking.

Cast-in-place concrete includes stamped concrete, which allows for creating a wide variety of paving patterns and textures through the use of rubber molds that are applied to the concrete paving before it dries (figure 5).

Stone:
A variety of effects can be achieved through the use of stone (or marble or granite) for paving. Stone paving pieces can consist of geometrically cut pieces, usually squares or rectangles (figure 6), and also of irregular pieces. Irregular stone paving tiles usually are leftover pieces resulting from the stone cutting process, and can be obtained at relatively low prices (figure 7).

Different colors of stone can be combined to create varying effects. Also, if a surface will not be used primarily for utilitarian purposes such as walking or the playing of children, then consider covering it with loose pieces of crushed stone, such as decomposed gravel, or river run rocks. One advantage of such ground covers is that they usually do not require any bedding and can be placed directly on the soil (figure 8).

A major advantage of using stone as a paving material in Jordan is that the country's quarries produce a wide variety of very high-quality stones.

Ceramic Tiles:
Ceramic tiles that are specially manufactured for outdoor use include various colors and textures (figure 9). They provide beautiful compositions that also are sturdy and that resist glare and slippage. However, ceramic tiles can be relatively expensive in relation to other paving choices such as concrete since their manufacturing is more complex. In addition, one might face difficulties after installing ceramic tiles if there is a need to carry out expansion or maintenance work since the original type of tiles might no longer be available in the market. Consequently, when using ceramic tiles, buy extra quantities and store them in case there is a need to replace any of the original tiles.

4. Joints Between Tiles

The joints between individual tiles can be used to provide effective touches that articulate outdoor paved surfaces. For example, use mortar that has a different color than the paving tiles to emphasize individual paving units. Also, widen or narrow the joints between tiles to either differentiate between individual tiles or to give the effect of a continuous surface. In addition, soil can be placed instead of mortar between the tiles and planted with a green cover to create pleasant combinations of green and paved areas. Such an arrangement does not require much irrigation since the water used for cleaning the paving tiles also serves to water the green areas planted between them.