A permeable paver is a paving unit or system that lets water pass through the surface into the ground, rather than shedding it as runoff like solid concrete or asphalt. Permeable pavers are used to manage stormwater, reduce flooding and pollution, and recharge groundwater — while still providing a firm, drivable or walkable surface. Grass and gravel pavers are two of the most permeable options.

NDS EZ Roll Gravel Pavers, a permeable paving surface.

What is a permeable paver?

Permeable pavers are engineered to be porous. Where solid pavement forces rain to run off into drains and streams, a permeable paver lets water filter down through the surface, into a stone base, and on into the soil. That infiltration is the whole point: it cuts runoff, filters pollutants, eases the load on storm systems during heavy rain, and returns water to the ground.

How the grid carries load

The reinforcing grid is installed over a compacted, free-draining base. It carries vehicle and foot loads and transfers that weight to the base, so the fill inside the cells — soil and grass, or gravel — is protected from compaction and rutting. Water infiltrates through the surface into the base and soil below, making the system both load-bearing and permeable.

Types of permeable pavers

• Grass pavers: a reinforcement grid filled with soil and grass; the surface is living lawn and fully permeable.
• Gravel pavers: the same grid filled with gravel, which stabilizes the stone so it does not migrate or rut while staying porous.
• Both use a structural grid to carry loads while keeping the surface open to water.

NDS EZ Roll Grass Pavers, a permeable grass surface.

The NDS paver systems

• EZ Roll Grass Pavers: a flexible honeycomb mat in 4 by 150 and 4 by 24 foot rolls; vehicle weight transfers to the base while grass grows through the cells.
• Tufftrack Grass Pavers: rigid 2 by 2 foot interlocking pavers, 1-1/2 inch thick, for higher-load uses like fire lanes, golf cart paths, and parking.
• EZ Roll Gravel Pavers: the roll-out honeycomb filled with gravel, made from 100 percent recycled material to reduce erosion and runoff.
• EZ Marker: a clip-in delineator that snaps into the cells to mark lanes, stalls, and fire lanes.

Benefits of permeable pavers

• Stormwater management: infiltration reduces runoff volume and peak flow.
• Pollution control: water filters through the base instead of sheeting pollutants into waterways.
• Groundwater recharge: rain returns to the soil.
• Cooler, greener surfaces: grass and gravel do not store and radiate heat like asphalt.
• Regulatory help: can assist with impervious-surface and runoff limits.

Where permeable pavers are used

Permeable pavers suit driveways, parking areas and overflow lots, fire lanes, paths, and access roads — anywhere a firm surface is needed but runoff should be minimized. The right choice between grass and gravel depends on the look you want and the traffic the surface will see.

Installation: base prep and steps

NDS EZ Roll Grass Pavers are designed to be placed on an engineer-specified compacted base. The base is what carries the vehicle load, so base preparation is the most important part of the job. A typical sequence:

1. Excavate. Remove unsuitable soil and excavate deep enough for the aggregate base plus the paver and soil. Longview's product guidance calls for a 4 to 6 inch aggregate base directly below the pavers; without that base a "cookie cutter" effect occurs as the pavers punch into soft ground.
2. Place the base course. Use a free-draining aggregate (NDS suggests AASHTO #57 stone or a local equivalent), placed over the prepared subgrade in lifts not exceeding 6 inches.
3. Compact each lift. Compact every lift separately to a minimum of 95 percent Modified Proctor density, so the base is firm and uniform before the pavers go down.
4. Optional sandy loam layer. An engineer may add about 2 inches of sandy loam between the paver and the gravel base; if so, place a non-woven geotextile filter fabric between the sandy loam and the base to keep fines from migrating into the stone.
5. Roll out and connect the pavers. Unroll the mat over the prepared base; the top-down locking tabs snap together with no tools, and each 2 by 2 foot section has 72 honeycomb cells.
6. Stake the pavers. Anchor with the supplied stakes (each roll ships with 40 stakes, 12 inch by 3/8 inch galvanized, NDS part GPSTAKE), following the recommended staking pattern. Use edge restraints at borders to prevent creep.
7. Fill with soil and plant. Fill the cells to the top surface with sandy loam or loam soil (sand is not acceptable), leaving a minimum of 1-1/2 inches for grass pavers and soil. Seed, sod, or hydroseed, and plant within 30 days of installing the pavers.
8. Establish before traffic. Keep vehicles off until the grass is sufficiently established to handle traffic.

NDS EZ Roll Gravel Pavers install much like the grass version, but the rolls go down fabric-side-down and the cells are filled with gravel instead of soil and grass. A typical sequence:

1. Prepare and compact the base. Excavate and place a free-draining aggregate base; base course thickness depends on the native soil and the anticipated wheel loads. Compact the base with one to three passes of a 5-ton steel wheel roller or equivalent.
2. Consult a geotechnical engineer for weak soils. For poor subgrades (CBR under 5 percent or R-value under 10), NDS recommends the engineer of record consult a geotechnical engineer about soil modification and compaction.
3. Roll out fabric-side-down. The pavers come with a thermally welded geotextile (Typar) fabric that prevents gravel from migrating downward and is porous for stormwater. Lay one roll first, then pull the edge of the adjacent roll snug against it and connect the lateral snap locks.
4. Leave clearance and stake. Leave a 1 inch minimum clearance between the pavers and fixed objects or structures, and stake per the recommended pattern (stakes are included).
5. Fill with gravel. Fill the cells with gravel to finish the surface; the cells confine the stone so it cannot rut or migrate.

Load and durability specs

For context on why the base matters, the EZ Roll pavers have an unfilled compressive strength in the range of about 53,683 to 57,890 psf and are rated to support H-20 and H-25 vehicle loads, with a life expectancy of 25 years when well maintained. Each paver weighs about 2.31 pounds and is made of HDPE with UV inhibitors. Those load ratings assume a properly prepared and compacted base, which is why the base-prep steps above are not optional.

For complete installation specifications, download the official NDS EZ Roll Grass Pavers Installation Guide (PDF).

Frequently Asked Questions