Question 1

Under which CSI division is Flexus specified?

Accepted Answer

Flexus is specified under CSI Division 32 — Exterior Improvements. The most applicable section numbers are 32 14 13 (Permeable Unit Paving) for the permeable pavement category, or 32 14 16 (Permeable Surfacing) where the project manual uses that designation. The Flexus specification is provided as editable Division 32 language in the spec pack and can be adapted to project-specific lift, base, and edge restraint conditions.

Question 2

What LEED credits can Flexus contribute to?

Accepted Answer

Flexus can contribute to LEED v4 / v4.1 credits including Sustainable Sites (Rainwater Management for permeable surface, Heat Island Reduction for non-roof SR value, Open Space contributions), Materials & Resources (Building Product Disclosure and Optimization for recycled content from the SBR component), and Innovation in Design where stormwater treatment trains exceed prerequisites. Actual credit contribution depends on project design, scope, and documentation submitted to the certifying body.

Question 3

Is a CSI-formatted specification available?

Accepted Answer

Yes. A CSI three-part format specification for Flexus permeable pavement is available as part of the submittal-ready spec pack. The specification is formatted for Division 32 and is provided in editable form so it can be adapted to project-specific requirements including series (CP or AP), lift thickness, aggregate blend, base specification, and edge restraint conditions.

Question 4

Is Flexus referenced in any industry standards?

Accepted Answer

Flexus is a proprietary permeable pavement system within the broader category of resin-bound permeable pavements. The closest industry standards reference for permeable pavement system design is ASCE 68-18 (Permeable Interlocking Concrete Pavement) — which addresses PICP specifically but provides relevant context for permeable pavement site suitability, subbase design, and hydrologic sizing principles that apply to Flexus installations. Individual ASTM standards (C501, F1551, E303, D2859, G154) and EPA methods (1311, 1312, RCRA) are referenced directly in the spec pack.

Question 5

How is Flexus documented in a submittal package?

Accepted Answer

The Flexus submittal package — referred to as the spec pack — includes the product overview, CSI Division 32 specification language, installation guidelines, typical cross-section details, edge restraint detail options, ASTM test reports (C501 abrasion, F1551 permeability, E303 slip resistance, D2859 water absorption, G154 UV exposure), EPA leaching test reports (1311 TCLP, 1312 SPLP, RCRA metals), and a maintenance protocol. The complete package is available on request and can be tied to a live project for sealed delivery.

Question 6

Is Flexus appropriate for an ADA-aligned accessible route?

Accepted Answer

Flexus is designed to meet the ADA surface requirements of firm, stable, and slip-resistant when properly installed. Slip resistance is documented via ASTM E303 in the spec pack. Cross-slope must not exceed 2% and running slope must comply with applicable accessibility standards — these are field conditions controlled by the design and installation, not by the material itself. The specifier and contractor are responsible for confirming that the installed route meets local accessibility requirements.

Specification element	Flexus reference
CSI division	Division 32 — Exterior Improvements
Primary section	32 14 13 — Permeable Unit Paving (or 32 14 16 — Permeable Surfacing, per project manual conventions)
Format	CSI three-part (Part 1 General, Part 2 Products, Part 3 Execution), editable
Related sections	31 23 23 (Fill), 32 13 13 (Concrete Paving — for edge restraints), 32 17 23 (Pavement Markings — where applicable)
Performance requirements	Permeability per ASTM F1551, slip resistance per ASTM E303, abrasion resistance per ASTM C501
Product data	Series (CP or AP), lift thickness (1.5″ / 2.0″ / 2.5″), aggregate blend, binder type, base specification
Submittals	Manufacturer's data, mix design, ASTM/EPA test reports, installer qualifications, mock-up
Quality assurance	Manufacturer-installed by Flexus in-house crews, mock-up panel, in-process permeability verification (optional)

LEED credit category	Credit	Flexus contribution
Sustainable Sites	SS Credit: Rainwater Management	Direct — Flexus functions as a permeable surface, reducing effective impervious area and supporting on-site stormwater management to the 95th percentile event or local equivalent
Sustainable Sites	SS Credit: Heat Island Reduction (Non-roof)	Supporting — surface solar reflectance (SR) varies by aggregate blend. AP series light-tone blends and CP-150 neutral blend can contribute toward non-roof SR requirements; SR documentation available on request
Sustainable Sites	SS Credit: Open Space	Supporting — Flexus paths within open-space areas can support open-space credit calculations where local definitions accept permeable surfaces
Sustainable Sites	SS Credit: Site Development — Protect or Restore Habitat	Supporting — replacing impervious cover with Flexus reduces hardscape impact in restoration zones
Materials & Resources	MR Credit: Building Product Disclosure & Optimization — Sourcing of Raw Materials	Supporting — the SBR rubber component is post-consumer recycled content (sourced from end-of-life tire rubber); documentation provided in spec pack
Materials & Resources	MR Credit: Building Product Disclosure & Optimization — Material Ingredients	Supporting — material ingredient documentation available on request to assist with credit pursuit
Innovation	Innovation Credit (ID)	Potential — projects integrating Flexus into a stormwater treatment train that exceeds Rainwater Management prerequisites may pursue an ID credit for exemplary performance

Permeable pavement specification, LEED credit mapping, and submittal-ready documentation

CSI Division 32 — drop-in specification

LEED v4 / v4.1 credit contribution

Submittal package contents

Specifier FAQ

Specify with confidence