Why ECO: Installation

Permeable Paver Installation Guidelines
This overview is intended to be a basic guide. Detailed instructions can be obtained from EP Henry or in our Technical Resources section.

homeowner_why ECO_installationMaterials Needed
Open Graded Base: should be a clean stone (i.e. # 2 stone and AASHTO #57), which weighs approximately 120 pounds per cubic foot. Calculate the depth of stone using the average depth of the stone from the highest point to the lowest point (6-inch minimum depth for patios and walkways, 10-inch minimum depth for driveways). The maximum recommended depth of AASHTO #57 in the base is 4". The remaining depth of the base material should be #2 stone. Calculate the project area and include an additional 2 feet around the perimeter* and an additional 5% for losses.
(* Use of a compacted dense graded aggregate shoulder in the base where the base excavation terminates against soil will allow for a smaller over dig and the use of standard plastic edge restraints that can be spiked in place.)

  • Bedding Material: 3/8" minus chipped stone is required (i.e. AASHTO #8 crushed stone). 3/8" minus chipped stone weighs approximately 120 pounds per cubic foot. Calculate the volume for a 2-inch bedding layer over the project area. Add an additional 20 percent for filling joints and losses.
  • Pavers: ECO Pavers are sold by the square foot. Calculate the square footage needed for your project and add 5%-10% for cuts, waste, etc.
  • Edge Restraint: All exposed edges must be restrained. A 6" wide by 12" deep concrete curb is one option. Calculate the linear feet of edge restraint required. The curb should be either flush with the top of the pavers or set 1 1/2" below the top of paver if grass edge is desired. EP Henry's Curbstone can also be wet set in concrete as an alternative.

    Use of a compacted dense graded aggregate shoulder in the base where the base excavation terminates against soil will allow for a smaller over dig and the use of standard plastic edge restraints that can be spiked in place. This shoulder needs to be as wide as the compaction equipment is at the top, typically 18" - 24". A separation layer of non-woven geotextile such as Mirafi 160/140N is needed between the dense graded aggregate and the open graded stone in the base and sub-base stone to keep the fines in the dense graded aggregate from migrating into the voids of the open graded stone base.

    Plastic edge restraint can also be used on open graded stone base if it is stabilized with cross connecting geogrid wrapping the edge restraint. Consult EP Henry for more details.

  • Separation Fabric: A non-woven geotextile such as Mirafi 160/140N is recommended to be installed as a drainage and separation fabric between the AASHTO #57 open graded base and the natural subgrade soil. In addition, a layer of Mirafi 160/140N can be placed between the bedding stone and the open grade base to best maintain the bedding layer.

Layout & Preparation
Layout the limits of the driveway, the edge restraint system, and the overdig. Mark the limits of the excavation on the ground. Before digging, always call your local utility companies to locate and mark out any underground utilities.

Prepare Subgrade Soils
For best results, the finished subgrade should be level. Excavate the soil providing the minimum recommended thickness at the lowest point of the driveway. For instance, a 50' long driveway with a 1/4" per foot slope will require a depth of 10" of stone at the lowest point and a depth of 22" of stone at the highest point. Extend the excavation beyond the edges of the driveway to allow for the installation of the edge restraint system. The subgrade should be clean and free of any organic materials such as topsoil and have adequate bearing capacity. The subsurface should be firm and not rutted. If the subgrade appears weak or damp, contact a professional engineer for further assistance. Special note; the sub-base soil surface of the excavation should not be compacted.

Mirafi 160/140N geotextile fabric may be used as a separation and drainage layer between the open-graded stone base and natural subgrade soil. Place the geotextile material over the subgrade soil and up the sides of the excavation taking care to remove any wrinkles. Where seams cannot be avoided, overlap the edges of the fabric by a minimum of two feet.

Install Edge Restraints
Concrete edge restraints: place forms for the edge restraints using a steel reinforcing bar to anchor the forms in place. (If the steel bar does not readily puncture separation fabric if it was used, make a small incision in to it to avoid pulling the fabric). Install the forms so the top edges will be at the desired finished grade. The top edges may be left up to 1 ½" below the finished grade of the pavers to allow grass to be planted on top of the edge restraint. Trowel and tool the concrete after pouring to provide the desired finish. Where the depth of the excavation exceeds the recommended height of the edge restraints, the open graded base may be partially installed first.

Pre-cast concrete edge restraints may also be used on smaller installations. In addition, EP Henry's Curbstone may be used as an edge restraint when set in concrete.

Use of a compacted dense graded aggregate shoulder in the base where the base excavation terminates against soil will allow for a smaller over dig and the use of standard plastic edge restraints that can be spiked in place. This shoulder needs to be as wide as the compaction equipment is at the top, typically 18" -24". A separation layer of non-woven geotextile such as Mirafi 160/140N is needed between the dense graded aggregate and the open graded stone in the base and sub-base stone to keep the fines in the dense graded aggregate from migrating into the voids of the open graded stone base.

Plastic edge restraint can also be used on open graded stone base if it is stabilized with cross connecting geogrid wrapping the edge restraint. Consult EP Henry for more details.

Preparation of Open Graded Base
Open graded base materials must be free of fine materials allowing them to provide maximum storage capacity of runoff and ensuring a free flowing path to the soil. Take care not to track soil onto the fabric or allow sediment to wash into the excavation during construction, potentially clogging the system.

AASHTO #2 and #57 stone are recommended for this installation. The #2 stone sub-base (open graded) needs to be installed before placing the # 57 stone. A maximum of 4" of #57 stone is recommended in the base on top of the #2 stone. The remaining depth of base stone below the # 57 stone should be #2 stone. Place the #2 stone on the sub-base soil or on geotextile fabric if it is was used in a 6" layer and compact it. The material should be moist during installation.

If available, a 10-ton steel drum static roller should be used for compaction. A vibratory plate compactor can be used for smaller projects. There should be a minimum of four passes with the compactor or roller with no visible movement of the material. Continue installing the stone in layers until the desired elevation is reached. The base should be smooth and level when completed and there should not be more than a 1/4" gap at any point along a straight edge. R12.02

Bedding Layer
Using screed boards, spread a two-inch layer of moistened AASHTO #8 3/8" minus stone onto the open graded base. The 3/8" minus AASHTO #8 stone should be firmly set in the underlying stone. In order to ensure that the finer materials of the 3/8" minus AASHTO No. 8 stone do not migrate into the open graded base and cause settling, a separation fabric such as the one used under the open graded base may be used.

Install Pavers
Install the pavers in the desired pattern. For ECO pavers place the pavers in a stacked or running bond pattern, ensuring that the lugs are in direct contact. Pavers can be cut with a wet saw as needed. ECO Cobble may be installed in any standard pattern that uses 6"X 6" and 6"X 9" or either individual size. To protect the pavers during compaction, place a medium such as a piece of separation fabric between the plate compactor and the pavers. Using a 3-5 HP (5,000 pound force) vibrating plate compactor, begin at the outside perimeter and work inward. Make at least 2 passes over the pavers with the plate compactor. Fill paver voids with No. 8 stone level with the paver surface. Voids may be topped with colored decorative stone (1/2") if desired.

Engineering Notes

  1. For best results, subgrade soil infiltration rates should be confirmed. Soils should have better than 0.5"/hour infiltration rates.
  2. The bottom of the stone should be a minimum of 2' above the seasonally high water table.
  3. Avoid over compacting or contaminating the natural subgrade soils with excavation equipment.  Do not use compaction equipment on the natural subgrade soils.
  4. Underdrain piping and storage systems may be used if designed by a qualified professional engineer.
  5. For moist or subgrade soils with a high clay content consult a geotechnical engineer.
  6. A sieve analysis of the 3/8" minus bedding stone material and open-graded stone material should be reviewed to confirm it meets the following filter criteria:
  • D15 open graded base / D50 bedding material < 5 and D50 open graded base / D50 bedding material > 2
  • open graded base = AASHTO #2
  • open graded base = AASHTO #57
  • bedding material = AASHTO #8
  • D15 = sieve size for which 15 percent of material is smaller
  • D50 = sieve size for which 50 percent of material is smaller