Oaks Designer Resource Guide 6.0 (USA)



We’re in this together.

We know that your role as a designer is to bring the vision of your client to reality through your creativity, knowledge and skill. When specifying Oaks Landscape Products, we assure you that they will do more than just look great; your choices will function properly in their intended roles for the life of the project. To this end, this Designer Resource Guide provides a high-level summary of the design tools and resources available from the product experts at Oaks, as well as recommends which Oaks products are suitable for different applications so you can feel confident that your choices will exceed your clients’ expectations.

Paver: Presidio, Marble Grey and Onyx Wall: Proterra TM Split, Natural

We’re here to help you by understanding your needs... As a manufacturer of landscape products, we get the opportunity to talk with many design professionals, be they architects, landscape architects, landscape designers, planners or engineers. One common theme we’re hearing in these conversations is that there are simply too many product choices and too much information circulating for any design pro to be an expert on all things. The common request that filters out of these conversations is: Can we, the manufacturer, provide product specific expertise and guidance on how to properly use the products we make? Our answer is a resounding “Yes; it’s our pleasure to help”! This Designer Resources Guide, as well as our Continuing Education offering, were developed to provide the design community with the most up-to-date and unbiased technical support available. While this guide provides a high-level summary of the design tools and resources available from Oaks, it also identifies which Oaks products are best suited for different applications. Our Continuing Education offering focuses on innovative new topics such as:

1) F inding Balance Between Place and Movement using the Woonerf Concept

2) Stabilized Backfill Creates All New Opportunities for Segmental Retaining Walls

We want to be your One Trusted Source of not only a quality, versatile product range but also technical guidance and support. Contact your Oaks Sales Representative to arrange a Lunch and Learn session for your team, and learn more about how Oaks is always here to help.

> > > > We have the resources to help you every step of the way! DESIGN/ EVALUATION •  ASCE and CMHA Manuals and Software •  Capital and Life Cycle Costing Software •  ASTM site inspection protocols •  VESPA design software for retaining walls SPECIFICATION TENDER •  CSA and ASTM Standards •  Sample Specifications, Patterns, CAD details •  Direct design assistance complete with stamped drawings •  PAT paver pattern files for use in AutoCAD MAINTENANCE •  Oaks Maintenance Guides •  Warranty •  CSA/ASTM Quality Compliance Reports PLANNING •  Oaks Design Resource Guide •  Comprehensive library of supporting documentation •  Examples of existing LID BMP projects •  Environmental Product Declarations CONSTRUCTION •  Oaks Inspection Checklists •  CMHA Contractor Certification Training •  CMHA Inspector Certification Training



Product Technology and Quality

These advanced manufacturing technologies are used in select product lines to create a higher standard of material.

EliteFinish ™ is an advanced manufacturing process that delivers richer, more vibrant color and a harder wearing, more durable and smoother textured surface. The surface of our EliteFinish™ products is a specially engineered layer of finely-ground, durable aggregates combined with rich color and concentrated cement. The paver foundation uses coarser stone to ensure long term performance in application. The resulting product delivers an enhanced finish and greater structural integrity.

ColorBold ™ is an integral treatment employed during manufacturing that provides a new level of color longevity and stain resistance. ColorBold™ is a proprietary process where supplemental ingredients penetrate the surface of the product to become an integral part of the unit. Enhanced color depth, extended color durability, improved resistance to stains and acidic materials, as well as improved freeze-thaw capability due to decreased moisture absorption are all benefits delivered with products featuring ColorBold™. Other color enhancement products are sealers applied post production, after the concrete has been thoroughly cured; the chemical can only penetrate whatever surface voids are present, with the balance being left as a film on the paver surface.

Products with EliteFinish™: Molina ® 60mm, Market Paver, Molina ® 80mm, Eterna


Products with ColorBold™: Molina ® 60mm, Market Paver, Molina ® 80mm

Without ColorBold™

With ColorBold™

Durable, aggregate base for a strong foundation




For your convenience we have summarized what’s new in this edition…

Introduction 01 We’re Here to Help 02 Product Technology and Quality

Products 40 Terrace Tile NEW 41 Nueva ® Slab NEW SIZE 42 Molina ® 60mm NEW COLOR AND SIZES 42 Molina ® 60mm Ferro Finish NEW 43 Oasis NEW COLORS 43 Cassina NEW SIZE 44 Classic Paver NEW COLORS 45 Beaumont NEW 46 Enviro Midori NEW COLOR 46 Nueva ® Paver NEW SIZE 48 Molina ® 80mm NEW SIZE 48 Molina ® 80mm Ferro Finish NEW

Applications and Solutions 06 Segmental Concrete Pavement Systems 12 What is a Permeable Pavement? 21 Segmental Retaining and Architectural Walls

50 Aria Step NEW COLORS 50 Nueva ® Step NEW COLOR 51 Nueva ® Curb NEW 53 Nueva ® 150 Wall NEW COLORS 54 Nueva ® 75 Wall NEW COLORS

54 Ortana NEW COLORS 57 Modan NEW COLOR

Stay Up-to-Date!

Visit our interactive online designer resource guide for additional photo and video content and post-publication updates. Scan to view!



In this section... 06 Segmental Concrete Pavement Systems 08 Traffic Defines Product Choices 09 Pedestal Set Applications 09 Creating Patterns and Mosaics 10 Safe Pavements 11 Capital and Life Cycle Costing

12 What Is A Permeable Pavement? 13 Selecting Which PICP System To Use

13 PICP Pavement Design 14 Hydraulic Design Factors

15 Storm Water Quality Modelling 15 Storm Water Quantity Modelling 16 Paying Attention To The Details 18 Designing For Northern Climates

19 Economics Of PICP 20 PICP Maintenance

21 Segmental Retaining And Architectural Walls 22 Wall Classifications (Design Options) 23 Stabilized Backfill Wall 23 Multi Depth Gravity Wall 24 Wall Design – How Can Oaks Help? 25 General Costing Comparisons 25 Project Specific Quantity Estimates 26 Stamped Wall Drawings 27 Creating Outdoor Features Or Spaces 28 Getting Back To Nature With Planting Beds 29 Segmental Retaining Walls Increase Usable Space 30 Constructing Ramps, Staircases and Seating 31 Incorporating Guards, Fences and Barriers 35 Drainage Design and Water Considerations


Oaks Segmental Pavement Systems are developed for various degrees of traffic, living street appeal, permeable pavement applications and northern climates, with consideration for pedestrian safety and wheelchair accessibility. Whether your intent is to enhance an entrance way, build a staircase or manage grades, Oaks Wall Products offer you design solutions for a variety of wall classifications. This section will guide you through making the right choices for your project, including detailed installation techniques, design tips, capital/life cycle costing and maintenance considerations. Applications and Solutions

Paver: Enviro Midori, Custom Color



Segmental Concrete Pavement Systems There are several different locations pavers and slabs can be installed. Some of the most common are: at grade on native soil, over an existing concrete or asphalt road, or above grade on a concrete patio or roof deck. The following two pages provide guidance for the majority of these installation practices, while information on Pedestal Set applications is covered on Page 09. CAD details, material specifications and testing requirements, and installation instructions for each option are available online or upon request.



Fill joints with Jointing Sand

25mm of Bedding Sand

SUITABLE APPLICATIONS: Most pedestrian and vehicular projects. BENEFIT: Economical installation. DESIGN NOTES: See ASCE 58-16 for recommended base thickness subject to traffic conditions and subgrade soil type. Need for separation geotextile subject to subgrade soil type. Underdrains may be needed over tight soils (clays). INSTALLATION NOTES: Ensure subgrade is properly compacted before commencing with Granular A placement. See ICPI (Interlocking Concrete Pavement Institute) for recommended installation practices. SAND SET ON SUBGRADE

Minimum 2% slope to storm drain

Min 150mm Granular A (or equivalent)

Compacted native soil subgrade

Optional geotextile separation fabric


Fill joints with ASTM 8 Clear Stone (or equivalent)

SUITABLE APPLICATIONS: Most pedestrian and vehicular projects where stormwater management is also an objective. BENEFIT: Utilizes the same area for traffic/parking and storm water management, frees up other space onsite for revenue generating purposes. PERMEABLE STONE SET ON SUBGRADE DESIGN NOTES: See ASCE 68-18 for recommended base thickness subject to stormwater management goals, traffic conditions and subgrade soil type. Need for separation geotextile and/or liner, and underdrains, subject to site conditions. See Page 12 for more information. INSTALLATION NOTES: Consult with Oaks staff on providing contractor training to ensure correct installation practices are being followed.

50mm of ASTM 8 Clear Stone (or equivalent)

100mm ASTM 57 Clear stone (or equivalent)

ASTM 2 Clear stone (or equivalent), thickness based on site design

Optional geotextile and/or liner (see Page 14 for more details)

SAND SET OVERLAY ON CONCRETE OR ASPHALT AT GRADE SUITABLE APPLICATIONS: Recommended over weak native soils. Bituminous set for high traffic areas, crosswalks or intersections BENEFIT: Combines structural benefits of concrete/asphalt with the aesthetics of pavers and slabs. DESIGN NOTES: Drain holes are required throughout the pavement area to allow water in the bedding layer to easily drain. SAND SET OVERLAY ON CONCRETE OR ASPHALT AT GRADE

Fill joints with Polymeric Jointing Sand

25mm of Bedding Sand (add a bituminous binder in vehicular applications)

Minimum 2% slope to storm drain

INSTALLATION NOTES: Recommend stabilized jointing sand to minimize water infiltration and tighter height tolerances on the pavers or slabs. For bituminous set, consult with Oaks staff on providing contractor training to ensure correct installation practices are being followed.

Concrete or asphalt layer (designed by others)

Weep hole lled with gravel

Geotextile over weep holes



Fill joints with mortar or Polymeric Jointing Sand


SUITABLE APPLICATIONS: Interior applications over concrete. BENEFIT: Creates a very rigid surface.

18mm of latex mortar

DESIGN NOTES: For pavers or slabs with small joints, use polymeric sand in lieu of mortar between the units. Control joints in the reinforced concrete need to extend up through the mortar and pavers/slabs. INSTALLATION NOTES: When using mortar in the joints, be careful to prevent mortar from spilling over the joints, which stains pavers/slabs.

Reinforced Concrete (designed by others)

SAND SET ON CONCRETE PATIO OR ROOFDECK SUITABLE APPLICATIONS: Exterior patios or roofs over concrete decks. BENEFIT: Provides decorative surfacing over concrete that can be lifted/ replaced for maintenance or repairs. DESIGN NOTES: Concrete deck needs to be sloped away from building to drains as pavement surface follows same slope. Control joints in the reinforced concrete do not need to extend up through the bedding sand and pavers/slabs. Also, see Note 1 below. INSTALLATION NOTES: Geotextile required above protective board to prevent bedding sand loss. SAND SET ON CONCRETE ROOFTOP

Fill joints with Polymeric Jointing Sand 25mm of Bedding Sand

Minimum 2% slope to storm drain

Waterproof membrane Rigid insulation Protective Board Geotextile

PERMEABLE STONE SET ON CONCRETE PATIO OR ROOFDECK SUITABLE APPLICATIONS: Exterior patios or roofs over concrete decks where a flat pavement surface is preferred. BENEFIT: Same as previous, plus pavement surface can be at nominal drainage slope (drainage can occur in the aggregate base). PERMEABLE STONE SET ON CONCRETE ROOFTOP

Fill joints with ASTM 9 Clear Stone (or equivalent)

25mm of ASTM 9 Clear Stone (or equivalent)

ASTM 57 Clear stone (or equivalent), thickness varies

DESIGN NOTES: Concrete deck needs to be sloped away from building to drains; thickness of ASTM 57 varies as needed to provide flat pavement surface. Also, see Note 1 below. INSTALLATION NOTES: Size jointing material to accommodate joint width. ASTM 57 stone needs to be manufactured sharp stone (not round river rock) to prevent shifting.

Protective Board Geotextile

Rigid insulation

Waterproof membrane

HYBRID SAND/PERMEABLE STONE SET ON CONCRETE PATIO OR ROOFDECK SUITABLE APPLICATIONS: Exterior patios or roofs over concrete decks. BENEFIT: Provides increased subsurface drainage (over sand set) to better handle moisture that infiltrated through the joints. DESIGN NOTES: A separation geotextile is required between the bedding sand and ASTM 57 stone. Also, see Note 1 below. HYBRID SAND / PERMEABLE STONE SET ON CONCRETE ROOFTOP Minimum 2% slope to storm drain

Fill joints with Jointing Sand

25mm of Bedding Sand

Separation Geotextile

ASTM 57 Clear stone (or equivalent), thickness varies

Wrap in geotextile to prevent aggregate loss

Note 1: On all concrete patio or roof deck applications, the roof drains need to have side slots that extend down to the waterproof membrane so that any moisture below the pavers can escape. Wrap the outside of the drain with geotextile to prevent bedding material loss.

Protective Board Geotextile

Rigid insulation

Waterproof membrane

Slots for roof drain to extend to waterproof membrane



Traffic Defines Product Choices Designers often ask where we recommend each of our pavers and slabs can be used. Given that the answer is dependant on what will be on the pavement, we have identified eight primary commercial Pavement Classifications with each representing a different traffic and/or vehicle weight scenario. The suitability of our pavers and slabs relative to each classification was then evaluated based on aspect ratio and/or finite element analysis results assuming a Sand Set on Subgrade installation; see Oaks Tech Note L6 – Structural Design of Vehicular Paver Systems for more information. In the Products section (starting on Page 38) the icons below are used to identify which Pavement Classifications each of our pavers and slabs are recommended for.


PEDESTRIAN PLAZAS There will be no vehicular traffic on these areas (rooftop, courtyards, pool decks).

EMERGENCY AND MAINTENANCE ACCESS ROUTES Although intended primarily for pedestrian access, there can be the occasional maintenance, snow removal or emergency response vehicle (plazas, sidewalks).

PASSENGER CARS ONLY These are areas with restricted access to private passenger vehicles (residential driveways, staff parking lots or restaurant drive thru corridors).

CARS AND LIGHT TRUCKS Open parking areas mostly used by private passenger vehicles and occasional light delivery trucks or small shuttle buses (restaurant parking, hotel or business entrances).

OCCASIONAL HEAVY VEHICLE USE Open parking areas used by occasional heavy vehicles (garbage collection routes at businesses or townhouses).


MUNICIPAL MIXED USE Any municipal street or private road where there is a general mix of traffic.

INDUSTRIAL AREAS Regular construction,

Open parking areas used by regular heavy vehicles (Mall entrances, bus/delivery routes, or dealership unloading areas).

operational equipment, or heavy vehicular traffic (Manufacturing facilities, ports, terminals).


Pedestal Set Applications Another question we often get is “what product(s) do you recommend for pedestal set applications”? For those not familiar with pedestal set applications, plastic spacers or pedestals are used to elevate concrete slabs over a built up roof to create an elevated deck. This is generally done to create a horizontal (i.e. easily navigable) surface over a roof deck that is otherwise uneven or sloping, or above ductwork, service pipes or electrical cabling on the rooftop. Unfortunately, prior to 2022 there was no production standard for slabs used in pedestal applications so we refrained from recommending any products. However, in 2021 it was determined that a “2000 lb center load test applied to full size slabs” would be the recommended standard; we then used this to validate the acceptability of our Molina ® (60mm) 24 x 24 Stone (see page 42) for use in pedestal applications.

Full-Size Slab, Corner Support Testing

Creating Patterns and Mosaics One of the main reasons that Oaks Segmental Pavements are used by design professionals is the variety of colors, sizes and textures available. You can create anything from simple geometric patterns to random layouts to complex mosaics. When reviewing your options, it is important to note that some of our products come pre-blended with multiple-sized pieces in a bundle, while other products have several separately-packaged size, color and/or texture options that can be blended on site based on the design. The Product Summary pages indicate which products come in pre-blended or separately packaged bundles. PAT (pattern image) files are now available for Oaks pavers. We have made it easier for you to auto-fill design areas and rotate and scale patterns as needed. Copy our PAT files into the default AutoCAD support folder for hatch patterns, and Oaks patterns will be listed in your hatch menu.

PAT FILES FOR ALL OUR PAVER AND SLAB PRODUCTS ARE AVAILABLE ONLINE! Visit the RESOURCES section of our website: www.bramptonbrick.com/en/resource-search. There you’ll find everything from laying pattern summaries to AutoCAD patterns, drawings and files.



Safe Pavements - Trips, Slips and Wheelchair Accessibility

Accessibility standards and building codes deal with individual elements of pavement safety. But there is no one regulation that clearly defines a truly safe pavement for all users. To help us develop products that are safe and comfortable for everyone, Oaks reviews and adopts design standards used by other industries.


This guideline limits the maximum grate hole size to 0.31” (8mm) to help prevent heels from entering paver joints, causing injury or falls. We use it to develop our paving products, including permeable pavers. This size is well below Ontario’s Accessibility Standard of 20mm and the US ADA Standard of 13mm, which focus on wheelchair tires and cane tips.


We tested various paver and slab textures (from smooth to textured) and finishes (including EliteFinish™ and ColorBold™) to find out how changes affect slip resistance. All of our products exceeded the recommended DCOF (dynamic coefficient of friction) of 0.42 set by ANSI A137.1 for ceramic tile. Details on the DCOF testing can be found in Oaks Tech Note L2 – Coefficient of Friction Testing for Pavers and Slabs.

WHEELCHAIR VIBRATION ASTM E3028 Standard Practice for Computing Wheelchair Pathway Roughness Index as Related to Comfort, Passability and Whole Body Vibrations from Longitudinal Profile Measurements PathMeT’s was used to measure the Wheelchair Pathway Roughness Index (WPRI) for a number of pavement surfaces. The results showed that pavers/slabs with 2mm wide chamfers have less of an impact on wheelchair users than even poured concrete surfaces. For this reason, all recently developed Oaks products – Eterna, Molina ® , Presidio, Nueva ® Paver, Nueva ® Slab, and Market Paver – have micro-chamfers (less than 2mm wide).

H-20 AND HS-20 LOADING Designers use H-20 or HS-20 from AASHTO to express the extreme load effect created by heavy vehicles (transports, buses and fire trucks) on bridges or other suspended segments such as lids on manholes. Paver systems are installed on a fully supportive base, and are in no way suspended over an opening into which a passing vehicle can collapse; therefore, H-20 or HS-20 loading design principles are not applicable. Refer to Page 08 Pavement Classifications for recommendations on selecting products based on traffic conditions.

H-20 Loading

HS-20 Loading

8,000 lbs

32,000 lbs 8,000 lbs32,000 lbs

32,000 lbs


Capital and Life Cycle Costing

CAPITAL COST According to an economic analysis report performed by Pavement Technologies Solutions, there are three primary factors that dictate whether a paver installation can be cost competitive to a traditional asphalt pavement, namely: • the present cost of asphalt, which fluctuates with the price of oil • the cost of the paver • the method of paver installation For our part, Oaks offers several economical machine install products.

Paver: Hydr’eau Pave

MACHINE INSTALLATION: Some of our products are manufactured in pre-set patterns for optional machine installation (see the adjacent icon). Mechanical installation can reduce costs significantly for projects over 1,000 square meters (10,000 square feet). Please contact us for product-specific stitching details and more information about mechanical installation.

What is the expected service life of a sidewalk?

LIFE CYCLE ANALYSIS It has long been accepted that maintenance and rehabilitation costs - not just initial capital costs - should be considered when conducting an LCCA for pavements. “Life Cycle Cost Management of Interlocking Concrete Block Pavements – Methodology Report and Software” was developed by Applied Research Associated of Toronto to conduct LCCA for different pavement options including asphalt, cast-in-place concrete and segmental pavements. Please contact us for copies of the report and the software.

Concrete 80 years

Pavers 80 years

Asphalt 40 years

Source: Federation of Canadian Municipalities

UTILITY MAINTENANCE Segmental pavements offer the advantage of being able to remove and reinstate the wearing course, which can reduce labor, disposal and material replacement costs. There is no need for short-term patching products, and there are no changes to the area’s overall appearance when complete. This alone can save significant costs. Helpful Maintenance Tools: • Interlocking Concrete Block Pavement Distress Manual • Asset Management and Pavement Performance Prediction through Pavement Condition Index (Report and Software) • ICPI Tech Specs 19 & 23 • Oaks Tech Notes L3 and L4



What is a Permeable Pavement?

Permeable pavements are pavement systems that allow water to pass through the surface in to an open-graded aggregate base. Widely recognized as a Low Impact Development (LID) strategy, Oaks permeable pavements conform to municipal storm water regulations.

Associated benefits may include: 1. On-site storm water quantity management 2. Improved water quality 3. Groundwater and tree root zone recharge

4. Reduced hydraulic, erosion and thermal impacts to receiving waters 5. Possible reduction or elimination of traditional storm water management infrastructure

PERMEABLE PAVEMENT SYSTEM Below are the main components of a Permeable Interlocking Concrete Pavement (PICP) system.

Concrete Curb

Concrete Pavers

Open Graded Bedding Layer

Permeable Joint Material

Open Graded Base Reservoir

Open Graded Sub-base

Geotextile (optional) in Full- or Partial Infiltration systems, liner in No-Infiltration systems

Underdrain (optional in Full-Infiltration systems) Soil Subgrade (Uncompacted for Full- and Partial- Infiltration systems, compacted for No- Infiltration systems)

ASTM No. 8 Grading Requirements Jointing and Bedding Aggregates

Sieve Size 12.5 mm (1/2 in.) 9.5 mm (3/8 in.) 4.75 mm (No. 4) 2.36 mm (No. 8) 1.16 mm (No. 16)

Percent Passing 100 85 to 100 10 to 30 0 to 10 0 to 5

ASTM No. 57 Grading Requirements Base Aggregates

Sieve Size 37.5 mm (1 1/2 in.) 25 mm (1 in.) 12.5 mm (1/2 in.) 4.75 mm (No. 4) 2.36 mm (No. 8)

Percent Passing 100 95 to 100 25 to 60 0 to 10 0 to 5

(commonly referred to as 1/4” clear stone)

ASTM No. 2 Grading Requirements Subbase Aggregate

Sieve Size 75 mm (3 in.) 63 mm (2 1/2 in.) 50 mm (2 in.) 37.5 mm (1 1/2 in.) 19 mm (3/4 in.)

Percent Passing 100 90 to 100 35 to 70 0 to 15 0 to 5

(commonly referred to as 3/4” clear stone)

All aggregate types listed should have less than 2% passing the No. 200 sieve, and should be manufactured sharp stone (not river rock)

(commonly referred to as rail ballast)

This symbol is used in the Products section of this Designer Resource Guide to indicate a permeable paving product. Contact us if you need help sourcing open-graded aggregate materials.


Some jurisdictions offer incentives for storm water quantity reduction or have limits on impervious cover; where this is the case, we recommend that you discuss using PCIP with your local municipal and/or regulatory agency before proceeding with your project. If the agency is not familiar with PICP, Oaks staff can provide in-house training and design support. Some common misconceptions about PICP: 1.  PICP can not be used in vehicular applications. Permeable pavers are suitable for a wide range of vehicular applications, provided that speed limits are less than 65 km/hr (40mph). 2.  PICP are not safe in pedestrian areas. Early versions of permeable pavers were a concern for pedestrians because of their large openings. Oaks more modern permeable pavers are designed to be safe for wheelchairs and pedestrians, and are heel-safe. (Details on Page 10) 3.  PICP cannot be used on clay soils. Provided that the system is designed accordingly, PICP can be used on any type of soil. (Details below) 4.  PICP systems are too expensive to build and maintain. Factoring the total cost of pavement, drainage infrastructure, storm water quality management and land, PICP can be a cost-effective option. (Details on page 19) Selecting Which PICP System To Use PERMEABLE PAVEMENT TYPES There are three main types of Permeable Pavement designs: Full-Infiltration, Partial-Infiltration and No-Infiltration, each referring to the amount of water that infiltrates into the native sub-grade.



FULL INFILTRATION: Use Full-Infiltration systems where the infiltration rate of the native soils exceeds the amount of water added to the PICP system. Underdrains and geotextile are optional. PARTIAL INFILTRATION: Use Partial-Infiltration systems where the amount of water added to the PICP system exceeds the infiltration rate of the native soil and some degree of water storage is required. Include an under-drain and an outlet control device (see Page 16) to control the water storage depth in the sub-base.





NO INFILTRATION: Use No-Infiltration systems over very low permeability, swelling or contaminated soils, or where water harvesting is an objective. Include an under- drain and impermeable liner (on bottom and sides of the system).


PIPC Pavement Design

ASCE 68-18 Permeable Interlocking Concrete Pavement was developed to provide design, construction and maintenance guidance for permeable interlocking concrete pavements to achieve storm water management goals while providing a structurally adequate pavement section to accommodate the anticipated vehicular loading in a cost efficient manner.

For copies of the ASCE Manual, or to receive a lunch and learn on the topic by one of its authors , contact Oaks staff.



Hydraulic Design Factors


On-site infiltration testing should be done whenever possible to determine site values. Oaks recommends following the protocols laid out in Appendix C of the TRCA/CVC Low Impact Development Stormwater Management Planning and Design Guide. Double-ring infiltrometer or Guelph Permeameter testing should be used as the results are more accurate (they estimate the vertical movement of water only). The test should be done at the bottom elevation of the proposed subbase, which is where sub-grade infiltration will take place in the finished pavement. It should also be verified that the depth to the seasonably high water table (SHWT) is not within 1 meter (3 feet) of the subbase. ASSESSING INFILTRATION RATES OF SOILS As part of its Waste Water Flow Management Plan, the City of Toronto summarized the distribution of rainfall events for 16 rainfall stations across the city. The study concluded that 54% of daily storms in Toronto produce less than 5mm of precipitation, and 98% less than 35mm. This table shows sample infiltration rates for different soils. Precipitation of 1.5mm/hour for silty clay may not seem enough to work with a PICP system. But, comparing the daily total (36mm of water infiltration) to the results of the previous study, and it becomes apparent that this infiltration rate exceeds even the 98th percentile of storm events in Toronto. In other words, even over silty clay storm water will infiltrate into the sub-grade within the same day as the storm event in all but the most severe storms.

Double Ring Infiltrometer

Proposed Subgrade

3 ft.





210mm (8.27")


26mm (1")


7mm (0.27")


1.5mm (0.06")


0.5mm (0.02")

Source: Porous Pavements

CONTRIBUTING WATER TO PICP Many agency regulations allow PICP systems to receive run-on from roofs (see adjacent photo), adjacent impervious pavements, and/or stabilized pervious areas (such as lawns). Although these regulations typically specify a maximum run-on ratio (compared to PICP surface area), Oaks recommends that you perform a water balance analysis to determine if the system can accommodate the additional storm water. Adjust the design details as required. To quantify the run-on, define the total area of each run-on source and estimate the contributing runoff from each source using the adjusted design storm(s) based on standard run-off practices. Be sure to also consider the potential for increased sediment and contaminant loads associated with the additional run-on. A sediment control chamber may be needed. (See Page 16)


Storm Water Quality Modelling Several jurisdictions place restrictions on the amount of Total Suspended Solids (TSS) that can be discharged from a site to the receiving storm water systems. There are two generally recognized methods of TSS management with permeable pavements. The first is filtration/straining as surface water infiltrates down through the jointing aggregate between the permeable pavers. Research at Florida Gulf Coast University determined that removal efficiency is a function of the size distribution of the particulate and the grain size of the jointing aggregate. Assuming ASTM #8 stone in the joints, the projected removal efficiency of an NJCAT gradation material is between 61 and 74%, while the removal efficiency of an MTO winter sand approaches 100%. The second method of preventing TSS from being discharged to the storm water system is, like with other infiltration practices, related to the infiltration capacity of the subgrade soils. To quantify the TSS removal resulting from infiltration, a water balance needs to be conducted to define what percentage of water that enters the base/subbase infiltrates into the subgrade (versus overflows/discharges through the drain). Depending on the native soil type and system design, the percentage of infiltration can range from 0 to 100%, with the resulting reduction in the remaining TSS being proportional. Storm Water Quantity Modelling

Storm water quantity modelling is performed to calculate and compare the following conditions: pre-development, post-development (uncontrolled), and post-development with BMP practices in place. Since there are no default values for PICP using the Soil Conservation Service (SCS) Curve Numbers (CN) method, it is up to you to determine them. Start by calculating the expected runoff from the surface of the pavers based on the typical CN for impervious surfaces (CN=98) using the traditional SCS equations below. Remember that a typical 85%-95% solid PICP surface experiences losses similar to traditional pavements due to the cooling/wetting of the paver surface. Where: Q = Total runoff depth (in.) P = Total precipitation depth (in.)

Q = (P - Ia)2 / (P - Ia + S) S = 1000/CN – 10

Ia = Initial abstraction of losses before runoff begins (in.) S = Potential maximum retention after runoff begins (in.)

With traditional pavements, excess water collects and sheet flows off the pavement surface. With PICP, excess water infiltrates through the joints between the pavers and into the base/sub-base. Surface overflow occurs only after the infiltration capacity of the sub-grade and/or the storage depth of the reservoir is exceeded. The equations used to calculate adjusted flows (Qadj) and adjusted CN (CNadj) are as follows: Where:

Qadj = Q – Ts - Ti

CNadj = Adjusted curve number Qadj = Adjusted runoff depth (in.) TS = Depth of water storage within aggregate reservoir (in.) Ti = Depth of water infiltrating into the subgrade over the duration of the design storm (in.)

1000 10 + 5P + 10Q adj – 10(Q adj 2 + 1.25Q adj P) 1/2

CN adj =

Examples: 100 yr 24 Hr duration precipitation depth (P) = 8 in; for an asphalt pavement with CN = 98, Q = 7.76 in

Over clay soil using a No Exfilration System

Over silty clay soil using a Parial Exfilration System

Over silt using a Full Exfilration System

Ts = 4.8 in (using a 12” thick base) Ti = 0 (system is lined) Q adj = 7.76 - 4.8 - 0 = 2.96 CN adj = 57 (Underdrain discharge would be controlled using an orifice plate or similar)

Ts = 4.8 in (using a 12” thick base) Ti = 1.44 in/day (see page 16) Q adj = 7.76 - 4.8 - 1.44 = 1.52 CN adj = 43

Ts = 4 in (using a 10” thick base) Ti = 6.48 in/day (see page 16) Q adj = 7.76 - 4 - 6.48 < 0 CN adj = 0 (No underdrain used, balance of stored water would infiltrate)

(Underdrain raised to minimize discharge, balance of stored water would infiltrate)



Paying Attention To The Details

Set bottom of notch in weir plate to desired storage elevation in the Base/subbase

Concrete Permeable Pavers


Removable weir plate (slides into brackets mounted on opposite sides of the chamber)

Precast Concrete Curb

Bedding Layer (ASTM No. 8 Stone, or equivalent) 50mm (2”) thick Base Layer (ASTM No.57 Stone, or equivalent) Subbase Layer (ASTM No.2 Stone, or equivalent) Geotextile Separation Fabric

This device consists of a concrete or plastic vault with a weir plate through the middle. Use it with Partial-Infiltration systems to set the storage elevation of the base/sub-base (where the water does not discharge until it reaches the weir notch) or with No-Infiltration systems to regulate the outlet discharge rate (drill a flow restricting hole through the weir plate).

Solid Header Pipe to Outlet Control Structure

Perforated Collection Pipe within trench below Subbase, minimum 75mm pipe bedding (ASTM No. 57) on all side

Discharge pipe to storm sewer, or daylight to surface feature

Precast concrete or molded plastic chamber with removable lid

Downspout emergency overflow

Catch Basin with Grated Lid

Diffuser Pipe


When adding roof water and storm water from adjacent impervious surfaces, you may need a receiving structure to handle potential sediment and contaminant loads. This diagram shows a sediment control chamber. Please consult with Oaks staff for more information about available alternatives.


50mm minimum from bottom of permeable sub-base

100mm diameter minimum inlet from downspout

100mm diameter minimum outlet

Filter Unit

Cut liner so not visible and fasten to building wall


Concrete Permeable Pavers Slope to drain away from building

30 mil PVC Liner complete with 12 oz protective non- woven geotextile Optional Platon membrane (or equivalent) Expansion material

Geotextile separation fabric (as required) Subbase Layer (ASTM No.2 Stone, or equivalent) Base Layer (ASTM No.57 Stone, or equivalent) Bedding Layer (ASTM No. 8 Stone, or equivalent)

Building foundations should be protected from water infiltration by: sloping the PICP away from the building; waterproofing the building foundation; installing an impermeable liner near the foundation wall.

Existing building wall and foundation footing

Distance to suit local ground condition

Permeable native soil subgrade. DO NOT compact unless infiltration rate reduction is accounted for in the hydraulic design calculations.

Extend liner to bottom of building foundation




For slopes exceeding 5%, use geomembrane check dams to control down slope flows, distribute infiltration over the entire length of the slope and prevent surges from exiting the pavement system at the bottom of the slope.

Surface Water Flows through the No. 8, 89 or 9 stone jointing material between the pavers

Maximum Slope = 12%

Permeable Pavers

Impermeable Membrane (extends minimum 300mm (12”) back behind vertical section) Permeable Subgrade. Prepare according to recommendations in geotechnical report

Bedding Layer 2” ASTM No. 8 Stone

Base Layer 4” ASTM No. 57 Stone Subbase Layer Minimum 6” ASTM No. 2 Stone Optional Geotextile Separation Fabric on bottom and sides of open graded base

Maximum Storage Volume

Orifice Opening in Membrane

Bleed Hole in Membrane

Because conventional pavement bases and subbases are not designed for saturation, they require protection from water infiltration. Separate the two pavement systems with an impermeable barrier (geomembrane or concrete). Also consider sloping the PICP sub-grade away from the adjacent conventional pavements or installing under-drains at the interface. TRANSITIONS TO IMPERVIOUS SURFACES

200mm to 600mm (8” to 24”) wide rebar reinforced concrete header curb (designed by others). Elevation to be 6mm (1/4”) below adjacent pavers and asphalt. Set depth to subgrade.

Jointing Material to bottom of chamfer Concrete Pavers

Saw cut pavement and seal joint

Maintain typical joint width adjacent to curb

Bedding Layer

Base Layer Subbase Layer

Existing asphalt pavement Compacted aggregate base

Optional geotextile around base and subbase

Soil Subgrade



Designing For Northern Climates

Because winter conditions place unique demands on Permeable Pavements, extensive research has been done by the TRCA, the University of New Hampshire and the US EPA among others to evaluate how they perform in cold climates. These are some of the findings. SNOW AND ICE COVER Surface accumulations of snow can occur on Permeable Pavement in the winter. Snow has to melt before it can infiltrate. As with any other paving surface, if the Permeable Pavement is not cleared before traffic drives on the surface, snow packing and ice formation may occur. To prevent ice formation, we recommend traditional snow plowing followed by spreading traction control aggregate as required. Instead of sand, spread the same aggregate used in the Permeable Paver joints.

Paver: Avenue Series

Applying anti-icing or pre-wetting chemicals to Permeable Pavement is not recommended. Anti-icing agents, which melt snow before it can become compacted into ice, will likely infiltrate into the system before a storm and impact local groundwater systems. And their magnesium or calcium chloride ingredients chemically attack the cement bond, causing the pavers to disintegrate. If the use of de-icing salts is required, as in the case of a zero ice policy, it is important to note an observation from the University of New Hampshire Stormwater Center: the use of permeable pavements resulted in a 75% average reduction in annual salt. Initial melt water was able to drain, leaving no standing water to re-freeze on the surface.

SURFACE INFILTRATION RATES Except when packed ice is present on the surface (as noted above), surface infiltration rates of Permeable Pavement are not adversely impacted in cold climates. Although the jointing and reservoir aggregates may become frozen, they still maintain their porosity and permeability. FROST PENETRATION Road construction protocol calls for a non-frost susceptible material for a percentage of the frost penetration depth. Because Permeable Pavement profiles use non-frost susceptible materials (i.e. open graded aggregates) and are normally deeper than non permeable profiles, most Permeable Pavements in cold climates have not shown any slumping or frost heaving after years of monitoring. Where water may be detained for an extended period of time or sub­ grade soils are prone to differential frost heave (silts), deepening the road profile can be considered. If water freezes in the reservoir, it can expand into the open voids of the base/sub-base without heaving the pavement. Base/sub-base aggregates are also not likely to develop frost lenses (which cause differential frost heave) due to the lack of fines. Permeable Pavement reservoirs tend to thaw more rapidly due to infiltrating melt water.

Winter data showed permeable pavement systems function well even during freezing temperatures.

Source: TRCA

0 1 2 3 4 5 6

Porous Pavement


Dense Pavement


30 60

90 120 150 180 210 240


Source: Porous Pavements


Economics Of PICP

CAPITAL COST ANALYSIS To prepare a true capital cost comparison between Permeable Pavements and traditional practices, three areas of the development need to be considered: 1. Road Infrastructure – permeable pavers are installed the same way as standard pavers, with significant cost saving through mechanical installation (see Page 11). 2. Storm Water Infrastructure – permeable pavements can reduce and even eliminate the need for traditional storm water infrastructure. The entire pavement surface is one large catch basin/filter, with base/sub-base aggregates providing retention/detention and lateral flow where required. 3. Income Generating Footprint – when retention/detention ponds are used, they can take up a lot of property. Consider the profitability of that portion of land if it were available for development, as well as its possible effects on property values. Oaks can provide you with capital cost comparison spreadsheets to help identify the different cost components that should be considered.

< Option 1 – Traditional storm water management uses a retention pond that consumes 20% of the property footprint. PROPOSED RETAIL STORE



RECOVERED DEVELOPMENT AREA Using PICP created a 20% increase in usable (i.e. revenue generating) land
















Option 2 – Using PICP to manage onsite storm water, gains 20% of the property footprint for additional parking and revenue generating buildings. > ENTRANCE ROAD





LIFE CYCLE/BENEFIT COST ANALYSIS We recommend using the TRCA Report “Assessment of Life Cycle Costs for Low Impact Development Storm Water Management Practices” and the “Low Impact Development Costing Tool” at the site-specific level. These were developed to help assess the design, installation, maintenance and rehabilitation costs over a 50 year period, based on northern conditions. We can help you work through the analysis to determine if Permeable Pavements can save you money. A number of reports are available for reference at the municipal level. For example, the Philadelphia Water Department determined that Low Impact Development initiatives would provide 20 times the benefits of traditional storm water infrastructure of an equal value.

LID practice life cycle costs were between 35 and 77% less than conventional Source: TRCA



PICP Maintenance

Refer to Oaks Tech Note L3 - Inspection, Maintenance and Repair of Permeable Pavements – for comprehensive PICP maintenance details. This is a brief summary of selected information.

ROUTINE MAINTENANCE AND INSPECTIONS PICP Maintenance prolongs the performance of the system and prevents problems from developing. Inspections ensure compliance with applicable regulations. This chart outlines recommended PICP routine maintenance and inspections.



Display clearly visible signage identifying the surface as a permeable pavement Vacuum sweep surface debris Check depth of joint material Check outlets are clear of debris Verify surface infiltration rate Conduct environmental compliance testing as required by the owner / regulatory agency

Improve visibility or replace as required

Twice annually Replenish material when >13mm from surface

Ongoing Annually As specified

Vacuum sweep the PICP surface using a regenerative air sweeper or similar device with a slight vacuum capable of lifting sediment. Do not use a conventional street sweeper, which can remove jointing material and spread additional smaller sediment over the surface. ASTM C1781 – Standard Test Method for Surface Infiltration Rate of Permeable Unit Pavement Systems is an easily reproducible and low-cost method of monitoring the performance of PICP. All you need is a 12” diameter plastic or metal ring, plumber’s putty, a 20L pail and a stop watch. Test areas that most frequently encounter sediment or debris.


Remedial maintenance involves rectifying a performance problem or safety concern that needs to be corrected.

REMEDIAL MAINTENANCE Repair ruts and deformations

FREQUENCY Ruts > 13mm from grade Paver > 6mm above or below grade

Reset shifted pavers Re-stripping of lines Replace broken pavers Power vacuum surface and replenish jointing material Clean out underdrains and inlet/outlet devices

As required As required Infiltration < 250mm/hr or surface ponding observed As required

When power vacuuming the surface of the pavers, use a vacuum truck (like an Elgin Whirlwind or equivalent).

There is an ongoing study through the University of Toronto and NSERC that is investigating maintenance best management practices for PICP. New and innovative maintenance equipment, like the Typhoon PICP Joint Cleaning system are being introduced and evaluated. Contact Oaks for updates and information on the test results. Please note: you do not have to vacuum the entire pavement surface unless needed; focus cleaning on specific areas prone to clogging. Joint material will also be removed, so be prepared to replace it immediately after the area is cleaned.


Segmental Retaining and Architectural Walls Segmental block walls and reinforced soil have been used for centuries (the most famous application is the Great Wall of China). Today’s Segmental Retaining and Architectural Walls are a modern version of this age-old technology. The diagram below lists the parts of a typical Segmental Retaining Wall, while diagrams on page 22 shows the five primary commercial Wall Classifications . Icons identify where each wall product is recommended for use in the Products pages.


Coping Units

Wall Batter (angle back from vertical)

Low Permeability Soil

Retained Soil

Wall Units

Compacted Reinforced Soil Zone

Geosynthetic Reinforcement

Gravel Fill (formerly drainage layer)

Leveling Pad

Foundation Soil

Drain Pipe

TIERED WALLS For each wall to be independent of the other, tiered walls need to be built using a 2:1 ratio, with the upper wall built a distance away from the lower wall of at least twice the height of the lower wall. As well, the upper wall must be equal to or less than the height of the lower wall. This is a general rule of thumb and exceptions do exist. When the distance between the lower and upper walls is less than twice the height of the lower wall, the walls become structurally dependent on each other. In this situation, it is important to take into account global stability - the resistance to overall mass movement of the whole segmental retaining wall system in a circular or sliding mode.

Dependent Terraced Walls

Independent Terraced Walls

Less than 2 x H

Medium Distance of 2 x H





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