Are You Permeable Enough?

PTC-Computer-Solutions-Parker-Associates-blog-February-2019-permeable-roadways

Surveys Show Consumers Want Green Communities

It may or may not come as surprise (and it really shouldn’t) that recent surveys conducted by independent researchers (see the article on Living Green here) have shown that consumers want to live in healthy Green Communities. The Real Estate Marketing Alliance (REMA) including Parker Associates and PTC work closely with several Green Builders who have committed to making community living a truly enjoyable synergy between their homes and their environments. Some of these initiatives include permeable paving among many other things.

But, the question here is, are you permeable enough to satisfy homeowners in your community? Permeable pavement (also known as pervious or porous concrete) is a specific type of pavement with a high porosity that allows rainwater to pass through it into the ground below.

Through this movement, pervious concrete mimics the natural process that occurs on the ground’s surface, consequently reducing runoff and returning water to underground aquifers.  It also traps suspended solids and pollutants, keeping them from polluting the water stream. Pervious concrete has many applications, most commonly:

  • low-volume pavements
  • residential roads and driveways
  • sidewalks
  • parking lots
  • low-water bridges
  • patios
  • well linings
  • walls (including load-bearing walls)
  • swimming pool decks

Porous Pavement

Pervious concrete was first seen in the 1800s in Europe and was used for various structural purposes, including load-bearing walls, infill panels, and pavement surfacing.  It became popular again overseas after World War II due to the scarcity of cement.

Although not a new innovation, pervious concrete has only been implemented in the United States in the past fifty years.  The concept was proposed in the 1960s in hopes of reducing floods, raising water tables, and replenishing aquifers, while a decade later the Environmental Protection Agency (EPA) began testing it to determine its cost and efficiency.  These tests were done at various sites in Delaware, Pennsylvania, and Texas, with Texas being the most significant site since it was the only one to have installed monitoring instruments.

The first official design guide for pervious pavement  was co-written in 1977 by Edmund Thelen and L. Fielding Howe in Philadelphia, PA.  Titled “Porous Pavement,” this document provided the groundwork for permeable pavement education and is still referred to today for guidelines and information.

Permeable concrete is now used in multiple cities throughout the U.S. and its number of applications has grown drastically over the past ten years, from driveways and sidewalks to commercial and multi-acre spaces.

The Ins and Outs of Permeable Pavement

Permeable concrete consists of cement, a coarse aggregate, and water, with little to no fine aggregates (sand or clay).  That is why permeable concrete has a very rough and uneven appearance.

The American Society for Testing and Materials (ASTM) has a set of standards for both pervious and non-pervious concrete. ASTM calls for the following percentage of air content (or voids) within pervious concrete:

  • 20% ± 5%: Low porosity, high strength
  • 30% ± 5%: High porosity, low strength

Porous Concrete

When compared to the required void percentage of non-porous concrete, which ranges from 3%-7.5%, the difference in overall structure can be easily seen.  The high void percentage required for pervious concrete lets stormwater run easily through the material and seep into the ground below, with typical flow rates ranging from two to 18 gallons per minute!  More standards and tests can be purchased or viewed on ASTM’s website.

Water and aggregate are added in specific amounts to attain pervious concrete with a high air content and just enough cementitious paste to coat particles and interconnect voids.  The low cement and high air content results in reduced strength, hindering pervious concrete from being used on highways, certain streets, or heavy loading areas.  The mixture of all added materials, however, can be altered to allow sufficient strength for certain needs.

Types of Pervious Concrete

There are multiple types of permeable concrete, all of which are used for different purposes:

  • Porous Asphalt is used on highways to remove excess water.
  • Single-Sized Aggregate contains no binder and is commonly known as loose gravel.  It can commonly be seen in very low-speed applications such as driveways or pathways.
  • Plastic Grids allow for a 100% porous system and are growing in popularity due to LEED project requirements.  These grids help reinforce gravel driveways, parking lots, and fire lanes.  Plastic grids can also be planted with grass.
  • Porous Turf can be used for areas with occasional parking, such as stadiums or churches.
  • Permeable Interlocking Concrete Pavers are individual units that can be laid out in an interlocking grid pattern, with in-between spaces commonly filled with grass or small stones.  This type of paving is popular in public areas due to its architectural appeal.
  • Permeable Clay Brick Pavers are similar to interlocking pavers, but are composed of fired clay.
  • Resin-Bound Paving is a mixture of a clear resin and aggregate, used for areas with pedestrian and vehicular traffic, including walkways, driveways, and parking lots.
  • Bound Recycled Glass Porous Pavement is a mixture of post-consumer glass with resins and binding agents. Made by FilterPave Products, this colorful pavement prevents glass waste from ending up in a landfill.  Recycled glass pavement is appropriate for both pedestrian and vehicular traffic.

Benefits of Pervious Concrete

Environmental Benefits

  • Eliminates runoff
  • Recharges groundwater
  • Traps suspended solids and pollutants
  • Reduces surface temperatures and, therefore, the heat island effect
  • Eliminates the need for retention basins and water collection areas

Financial Benefits

  • Eliminates costs for retention basins, curbs, gutters, and other water collection installations
  • In winter conditions, typically requires much less salt or other de-icing products than traditional pavement types
  • Lower installation costs (no underground piping, storm drains, or sloping/grading needed)
  • Low life-cycle costs with an equal life expectancy to that of regular concrete: 20 to 40 years when correctly installed

Factors to Keep in Mind

  • Runoff Volumes: A pervious pavement project should be properly designed to accommodate the amount of stormwater runoff that is expected in the area.  If not adequately designed, the water table below the pavement can rise, preventing stormwater from being absorbed into the ground.
  • Because pervious concrete has such a high void content and its overall strength is generally lower than that of regular concrete, it is not recommended for highways, high-volume streets, potential spill sites (in case of clogging), and heavy loading areas.
  • While it is estimated that porous concrete can be two to three times more expensive than regular asphalt or concrete, cost savings are simultaneously achieved as stormwater installations are not necessary.
  • Certain types of pervious pavements require frequent maintenance due to the possibility that solids and particles may get trapped and clog pavement pores.  If the proper “vacuuming” or flushing is not carried out, pervious concrete will assume the traits of impervious concrete.
  • Siting should be a major factor when considering permeable pavements.  If the ground surface exceeds a 20% slope, stormwater will run downhill over the permeable pavement as opposed to being absorbed by it as intended.

Green Parking

Permeable paving can be one part of building green parking lots, which can also include rain gardens, art, trees, solar covers, and other creative elements. Paving and landscaping choices have a large effect on the environmental impact of parking lots. For more information on green parking, visit Green Parking Council or see this Green Parking Lot Resource Guide from the EPA.

Conduct Surveys of Residents

Parker Associates has been involved in developing countless surveys through the years, and it’s questions like these that can help define what kind of buyer is in the market. Find out what consumers want before telling them what they want. They won’t want it. Consumer answers will lend answers to the questions we want to answer:

WHO? WHAT? HOW? CONSUMERS COME FIRST

Real estate marketing and sales relies first upon understanding the characteristics of potential consumers and their needs and preferences — WHO are these individuals and households for a particular marketplace in terms of age, income, household size and likely behavioral patterns.

Such consumer information is essential to creating the highest impact product to attract their attention — WHAT appearance and design features will match their needs and preferences at a feasible price range. For new homes, product includes regional and neighborhood attractions as well as community amenities and both the exterior and interior features of specific dwelling offerings. The tendency of consumers to relate to persons with similar age, income and household size characteristics provides a special attraction for most potential buyers.

The same consumer information provides the basis for cost-effective marketing strategies — HOW best to attract these consumers to contact the builder and visit the offerings at the most efficient time and cost outlay. Despite claims to the contrary, most real estate requires face-to-face contact with consumers to achieve sales. It cannot be sold by phone or even Internet communications.

These three simple words — WHO?  WHAT?  HOW?  — constitute the essence of efficient marketing and sales or leasing of new homes. They are the basis for Parker Associates’ success in guiding many community developers, hoteliers, and homebuilders toward rapid sellout of all types and prices of new homes and rental apartments. With modest modifications, they can be applied directly to retail, commercial and industrial real estate as well as housing.

The Parker Associates process starts with a confidential review and consultation to learn more about our processes. If you want our opinion, then Contact Us to put Parker Associates working for you.

Parker Associates works extensively on understanding your market, your consumer, and your goals. We don’t take guesses, we take the time and commit the resources to researching the market and the consumer to make sure we get it right.  We are YOUR advocate by being the CONSUMER’S advocate.

Spend time looking at what you are trying to acquire, develop, or sell to learn how you can improve the success of what you are offering. Parker Associates helps understand the consumer by answering WHO will buy, WHAT they will buy, and HOW they will buy it.  When the research is completed and the analysis is done, having the answers to these questions will reveal what will provide the best success for your project.  Keep asking WHO, WHAT, and HOW and keep developing to fit the need.

The Parker Associates process starts with a confidential review and consultation to learn more about our processes. Then Contact Us to put Parker Associates to work for you.

David WB Parker is a principal of Parker Associates of Jacksonville, Florida, marketing consultants to the real estate industry; President of PTC Computer Solutions, IT Specialist, and an active real estate sales professional with PARFAM REALTY based in Jacksonville, FL.  He can be reached at 904-607-8763 or via email davidp@ptccomputersolutions.com.

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