Turfstone Grid by Belgard

Permeable or Pervious

Understanding Permeable Paver Systems

What is Permeable Interlocking Concrete Pavement (PICP)?
PICP is a stormwater management solution that allows rainwater to filter through the joints between pavers, down through engineered aggregate layers, and into the soil below — reducing runoff, flooding, and pollution.

How the System Works

PICP is not just a surface material — it's a layered drainage system. From top to bottom:

• Pavers – Solid concrete units (3⅛"/80mm thick) with open joints filled with No. 8, 89, or 9 stone aggregate
• Bedding Layer – 2" ASTM No. 8 stone beneath the pavers
• Base Layer – Min. 4" ASTM No. 57 stone for structural support
• Subbase Layer – Min. 6" ASTM No. 2 stone for water storage and drainage
• Geotextile Filtration Fabric – Placed on the bottom and sides of the open-graded base (when required by a design engineer) to prevent soil migration
• Subgrade – Prepared native soil; depth and conditions determined by geotechnical analysis

Pedestrian-only applications may simplify to a single 6" ASTM No. 57 base layer.

Manufacturing Standards

Permeable concrete pavers are manufactured to meet:

• ASTM C936 – Solid Concrete Interlocking Paving Units
• ASTM C1782 – Segmental Concrete Paving Slabs
• CSA A231.1/A231.2 – Canadian standard for precast concrete pavers and slabs

Key Uses & Applications

• Driveways, parking lots, plazas, and pedestrian walkways
• Low Impact Development (LID) stormwater strategies
• Areas subject to local stormwater regulations or impervious surface limits
• Sites needing reduced heat island effect or improved groundwater recharge

Important Design Considerations

1. Subbase depth must be determined by site-specific hydraulic and structural engineering — not a one-size-fits-all spec.
2. Traffic loading affects paver dimensions and aspect ratios — consult a structural engineer for vehicular applications.
3. Geotechnical input is required to balance structural stability with soil infiltration rates.
4. Geotextile selection must be verified against clogging resistance and must meet AASHTO M-288 requirements.
5. Stone substitution – ASTM No. 2 stone in the subbase may be substituted with No. 3 or No. 4 stone where appropriate.

Maintenance & Long-Term Performance

All permeable pavements collect sediment over time, gradually reducing infiltration rate. This is expected and manageable:

• Sediment accumulates near the surface where it's easiest to remove
• Routine vacuum street sweeping is the primary maintenance method
• Surface infiltration testing should confirm rates exceed 100 in/hr after any major maintenance or restoration
• A site-specific Operations & Maintenance (O&M) Manual is recommended for commercial and municipal installations

Construction Site Protection Tips

Protecting a newly installed PICP system during ongoing construction is critical:

• Schedule PICP installation strategically — early installation allows it to serve as a sediment trap, with joint material replaced at project completion
• Avoid washout and debris from concrete, masonry, and drywall trades directly on the paver surface
• A sacrificial asphalt layer over the base aggregate can protect the system during heavy construction traffic, but must be removed and the base re-graded before final paver installation
• Plywood, tarps, and fabric covers have generally proven costly and ineffective as surface protection

Recommended Resources

• ASTM C936 Standard – Paver manufacturing specification
• AASHTO M-288 – Geotextile specification for filtration
• EPA Permeable Pavement Overview – LID stormwater context
• Interlocking Concrete Pavement Institute (ICPI) – Industry technical guidance and installer resources

*Special

Special Terms and Conditions for Special Order Materials

Special Orders may have Mold Charges, Set-Up Charges, and Add-On Fees.

Special Order Shapes

• 5 Cube Minimum for the designated Standard Color Offering
• Orders may not be cancelled once manufacturing begins
• Delivery to the job-site is to begin within 30 days after receipt on our yard, and 100% of the materials ordered must be delivered no later than 90 days after receipt on our yard
• Purchaser is responsible for determining all quantities
• Purchaser is required to pay for all materials ordered; if product comes on a Pallet you will be charged for a pallet
• 50% Deposit may be required at time of ordering
• Remaining 50% is due prior to shipment from manufacturer

White/Yellow Reflective Pavers

N/A — No longer available

Add-On Fees

Sizing Guide

Understanding paver specs helps you order the right product and calculate exactly what you need for your project.  Each product's packaging info is listed in your product descriptions.

Nominal vs. Actual Size The size listed in a product name (e.g., 4"x8") is the nominal size — the working dimension including a standard joint gap. The actual size is the physical measurement of the stone itself, which is slightly smaller. Both are listed on each product page.

Thickness & Use Case

• 3/4" (20mm) Porcelain — Residential & Commercial pedestrian & light vehicular
• 1" (25.4mm)  — Residential & Commercial pedestrian & light vehicular
• 1-5/8" (41.275mm) — Residential & Commercial pedestrian
• 2-3/8" (60mm) — Residential & Commercial pedestrian & light vehicular
• 2-1/4" — Residential & Commercial pedestrian & light vehicular
• 3-1/8" (80mm) — Commercial pedestrian & light vehicular
• 4" (100mm) — Heavy Industrial & commercial vehicular

Coverage & Pallet Coverage tells you how many square feet one pallet covers. To estimate your order: divide your total square footage by the coverage number, then round up. Always add 10% for cuts and waste.  Sales are sold in full pallet quantities.

Mix Ratios (3-Piece Systems) Some products ship as a pre-mixed pallet of multiple stone sizes. The mix ratio (e.g., 17/33/50%) reflects the proportion of each size per pallet — you cannot order individual sizes separately.

20mm Porcelain  pavers ship at 20mm thickness.

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