The proper installation of permeable paver systems is one of the most crucial steps in
ensuring their success. It is recommended that installation of interlocking concrete paving
blocks be performed by a contractor experienced with these systems. The interlocking blocks
can be installed either manually or mechanically but must be seated and leveled with a
vibratory plate compactor. Then the joints and drainage openings are filled with pervious
material through a combination of sweeping and vibrating. Grass and gravel pavers, on the
other hand, are designed for fast, low-cost installation. They are composed of flexible grids
that can be easily installed around obstructions and contours, cut with ordinary hand or power
tools, and do not require special fasteners or connection devices, forklifts, cranes or
concrete saws.
Although porous concrete is not shown in the photographs here, it, in particular, requires
high quality control during installation. For example, the amount and timing of the addition
of water to the mix is critical, and when improperly done, the mixture is useless as far as
permeability. It is absolutely crucial that a project be completed using a certified crew
specifically experienced with porous concrete.
Most permeable paver manufacturers include detailed construction specifications from which
installation time can be estimated using the project's area and crew size. However, as with
all construction activities, total time for installation can be affected by site and weather
conditions, timeliness of material shipments, crew productivity, and special installation
requirements. While a system based on interlocking concrete paving blocks or gravel pavers is
ready for use immediately after installation, grass pavers will typically require several
months for proper vegetative growth (sod can be applied for quicker use), and porous concrete
requires a covered curing period of about seven days.
The first step in
construction is excavation. Depths typically range from 8 to 15
inches, with about 12 inches being typical.
After excavation, the gravel layer is
installed, which serves as the strength of the paver system.
Once the gravel layer is placed, a permeable geotextile fabric can be
rolled on top of it.
This fabric separates the rock from the overlying sand layer. Wetting of
the sand should occur to even out the surface before placement of the pavement grid.
The concrete block or plastic grid layer goes on top of the sand. This
layer can be laid by hand...
...or equipment can be used to efficiently lay the interlocking concrete blocks, and certain
plastic grid pavers come in spools that are easy to roll.
After the paver grid is placed, the voids are filled with material. Just as
with the grid, various fill options are available depending on the system's use and purpose. Pea
gravel, larger washed gravel and loamy sand can all be used. For turf pavers, grass root systems
tend to flourish once stabilized.
