Masonry Magazine April 1995 Page. 20
DRAIN
GEOTEXTILE
MORTARLESS BRICK PAVING
SAND SETTING BED
COMPACTED
AGGREGATE BASE
COMPACTED
SUBGRADE
PRESSURE-TREATED
TIMBER
EDGING
Flexible Brick Paving
FIG. 3
MORTARED
BRICK PAVING
MORTAR
SETTING BED
DRAIN
CONCRETE BASE
COMPACTED SUBBASE
EXPANSION JOINT
BRICK EDGING
COMPACTED SUBGRADE
Mortared Brick Paving
FIG. 4
neath the pavement and usually lower installation costs.
The design of brick paving systems can be rather complex, depending on the size of the project. Technical Notes 14 Series discusses many of the design and construction parameters in more depth than in this Technical Notes. Only critical or unique information is contained here.
Patios and Walks
Some of the most widely used features of landscape design to which brick is adapted are patios and walks. Patios may be outdoor extensions of the indoor living space and supplement the activities of the occupant. Patios are often adjacent to living, family or dining rooms. Patios may be built as terraces, which are raised levels of earth supported on one or more sides by a wall or bank. A terrace is used to extend living space along a hillside.
Walks are often effectively used to provide an interesting and inviting entrance path to a garden or home. Walks may be used to define pedestrian travel routes and can provide geometric patterns in formal garden layouts. They can also serve as a path through a natural or garden setting.
Bases. The proper design and construction of the base is often the most critical element for long-term performance of the paving assembly. Insufficient base thickness or improperly compacted bases will lead to undulations (rutting) or cracking of the pavement. Appropriate base thickness depends on the type of loading and weathering it will receive. Most residential patios and terraces will only receive pedestrian traffic; therefore, the thickness may depend more on its resistance to frost heave. The minimum recommended base thickness is 4 in. (200 mm) for concrete, asphalt and aggregate bases. Thicker bases and the use of a subbase may be required in areas with poor soil conditions or soils that are constantly saturated. In these cases, the base should be increased in thickness based on local requirements.
Drainage. Drainage is another key design feature which affects long-term performance. Poor drainage will allow water to stand on the pavement and saturate the brick pavement. Problems resulting from poor drainage include deterioration of the paving, moss and algae growth and slippery pavements. Therefore, it is important to slope the pavement to keep water from collecting. Primary drainage of all pavements should occur on the surface. Drainage should occur away from buildings or other walls. For brick pavements, a slope of % to % in. per foot (1 to 2 mm per 100 mm) is recommended. Lesser slopes will allow water to accumulate. Steps and ramps must also be sloped to avoid standing water. Treads of steps should slope to % in. per foot (1 to 2 mm per 100 mm). Cross-slopes of the pavement help drain water off of the pavement, but the slope should not exceed 3 percent. Flexible brick pavements may allow some water to percolate down into the ground. In this case, subsurface drains may be necessary to remove water from the system.
Steps and Ramps
Steps and ramps are used to connect different levels for easy access. Steps have traditionally been used to allow movement up and down steep slopes or within structures. The size and configuration of steps is governed by a combination of physical human dimensions and aesthetics. Ramps are used on gentle slopes and are used to provide access for the physically impaired. Since ramps have low slopes, they will require more space than steps. Brick has been used successfully in all configurations of steps and ramps mainly because it is a small element which permits numerous configurations. Model building codes often dictate certain criteria for steps and ramps such as riser-tread relationships and minimum slip resistance. Other design issues that should be considered include structural support of the steps or ramps and other safety issues. Steps should be a minimum width of 60 in. (1.5 m) for public spaces, or 42 in. (1.1 m) for private residences. There should be at least two, preferably three or more steps, in a stepped walkway, since single steps can be overlooked and lead to trips.