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The Official Guide to Permeable Pavers and Porous Paving Systems

The Official Guide to Permeable Pavers and Porous Paving Systems

What Are Permeable Pavers?

Permeable Paving is a type of pavement or under-surface structure that supports the passage of rainfall or water run-off through the surface of the sub-surface below it. They are designed primarily to support the heavy load of traffic while also protecting the surface from compaction, and providing a green solution for your paving needs. Invisible Structures Grasspave2 and Gravelpave2 can support a wide range of traffic types from pedestrian foot traffic and residential parking to emergency vehicles!

Why Use Permeable Paving?

Using Permeable Pavement solutions reduces the risk of flooding, captures rainwater, and recharges the natural ground water. Porous Paving also protects natural environments from erosion and increased traffic that may affect the area. Employing the use of a permeable paving system provides superior protection against soil compaction while still maintaining the natural aesthetics of the landscape. Grasspave2 and Gravelpave2, made from 100% recycled plastic, provides ecologically friendly roadways, driveways, parking lots, and fire lanes, while simultaneously yielding a natural look dissimilar to the common materials used in landscaping and hardscaping. They can be used by themselves or in conjunction with other pavers to create park-like areas that are completely functional for everyday traffic and parking.

Permeable Pavers are designed to distribute the weight of the traffic, whether that be vehicle or person, through the structure itself and down to the base without causing any harm to the surface. Porous Paving materials have different percentages of void space that allows water to pass through to sub-soils at varying rates. This prevents any pooling or flooding and provides a structured surface that is multi-functional. Our trademark design offers ease of installation, reducing labor costs. Grasspave2 and Gravelpave2 bend natural variances of the landscape and can easily be cut to size with pruning shears to fit your custom landscape requirements.

Why Are They Required?

Porous Paving may be required on a municipal level, because Municipalities are beginning to regulate more heavily when it comes to impervious vs pervious surfaces in building construction and renovation. This regulation is to mitigate the effects of stormwaters, which can be harmful to the environment around us. In the past, we have created so many impervious surfaces when constructing our roadways and roofing, that we now need to combat that by creating more areas capable of capturing natural rainwater in order to recharge the groundwater.

How To Calculate Municipal Requirements?

To help keep you informed on the requirements of Porous Paving, we have provided a guide on how to easily calculate the municipal requirements if you fall under one. For this example, let’s say a building occupies 50% of a 10,000 sq ft lot and has 25% natural green space. The rest is currently impervious, which means they need to convert 10% of the impervious surface to a new porous surface, or 1,000 sq ft. Your area may or may not have porous paving requirements. If it does, here’s an example of how to calculate it (and if it doesn’t, it may soon):

  • If the building occupies 50% of a 10,000 sq ft lot, has 25% natural green space and the rest is currently impervious, they need to convert 10% of impervious surface to new porous surface (=1000sf).
  • If 65 impervious/35 pervious, then all new/rehab projects in that area need to have 35% pervious spaces on the lot. Existing natural green spaces count toward that 35%.

What Kind Of Environmental Benefits Are There?

There are many environmental benefits to using a Permeable Paving system. Environment benefits include reducing water pollution and toxins by naturally filtering the water as it runs through. Porous Pavers also prevent runoff, which when left untreated, can collect contaminants and increase temperatures as it travels. When this happens, it dangerously disrupts natural waterways while also increasing the chance of overwhelming local stormwater management systems. The disruption can lead to flooding and many other problems in both cities and residential areas. Porous Pavers capture hydrocarbons, and the Permeable Pavers with grass reduce CO2 levels. It also makes a better carbon sink than that of a forest.

Replacing concrete and asphalt with porous paving results in the reduction of both sound and heat in urban areas. Porous Pavers reduce noise because of the void space that lies within the structure. When a sound wave enters, the air movement is absorbed by these voids.

What Are The Basic Components To Permeable Pavers?

The basic components of the Porous Paving systems are as follows:
They begin with a Surface Layer that consists of grass, gravel, or porous concrete/asphalt. Next, comes the Porous Paving Structure. This layer is followed by a Structure Fill. It consists of sand or soil if required. Then comes the Porous Base Course, which is a layer that must meet loading requirements. The second to last layer in the paving system is the Geogrid or Geotextile Layer, which is not required by all manufacturers. Finally, the Existing Subgrade Soil sits on the bottom to provide a support base. The structures themselves may vary in material, size, shape, and PSI compressive strength. Varying specifications of both this layer and the Structure Fill layer are provided by manufacturers, however these are the general similarities.

What Are The 6 Factors That Differentiate Pavers?

There are six factors that contribute to differentiating Permeable Pavers: Cost, Functionality, Maintenance, Aesthetics, Ease of Installation, and Municipal Requirements.

  1. Cost – Consider both immediate and long-term costs associated with the product, such as potential repair and replacement, and how long the product and installation will last.
  2. Functionality – Determine how much traffic the specific project is likely to have and whether or not the installation is permanent. This is also when considering environmental factors would come into play.
  3. Maintenance – Take into account the standard maintenance and possible repairs that may need to be done on the project over the course of its lifetime to keep the paving system working well.
  4. Aesthetics – What will the finished installation look like? How much of the product will I physically see? These are both questions that should be asked when considering the Aesthetics factor.
  5. Ease of Installation – How much time will the total installation take? How much on-site man-power will be required is also an important consideration to be had.
  6. Municipal Requirements – If your municipality has requirements for impervious vs pervious surfaces, make sure to calculate these in when creating or renovating your project.

Difference In Paving mediums?

Porous Concrete and Asphalt:

This paving medium generally has a higher product cost, but installation cost is only slightly higher than regular concrete and asphalt due to its custom base course. Maintenance on this paving medium can be high as it can also crack over time. Porous Concrete and Asphalt has low void space so drainage functionality is lower than other pavers. It is indiscernible from regular streets and sidewalks if properly kept up so aesthetics resemble typical concrete and asphalt . The installation process is also essentially the same.

Rigid Plastic Porous Pavers:

The cost of this paving medium ranges from moderate to high depending on both the density of the paver, and the manufacturer. These Porous Pavers typically function well in normal conditions, however, they can tip and create uneven surfaces in colder climates. The Rigid Plastic Porous Pavers that come equipped with grass require roughly the same amount of maintenance as a regular grass lawn, and the gravel pavers are easily maintained by an occasional brushining of the loose gravel back into place. The void space on these pavers is high, making meeting municipal requirements easier than Porous Concrete Pavers.

Flexible Plastic Porous Pavers:

Flexible Plastic Porous Pavers fall in the moderate cost price range. The flexibility allows for soil expansion and can support freeze/thaw cycles while maintaining strength for any kind of traffic you may need to cater to. The Flexible Porous Grass Pavers require the same maintenance as a typical lawn with the exception that aeration is not allowed. The structure of the Flexible Porous Pavers is not seen from the surface, which allows for design flexibility.

How Do You Make A Choice?

All Porous Pavers offer a Greener Solution and environmentally better design choice than going with a traditional concrete or asphalt. When choosing, if you prioritize the most important elements of a project it will help to determine which type of paver is going to be the best option.

Considering LEED

When talking about green design and construction, it is important to consider LEED (Leadership in Energy and Environmental Design). LEED is the most common and widely used green building rating system in the world. This system provides a framework for highly efficient, and cost-saving green buildings. The benefit of using Porous Pavers is that it can add LEED Points to projects in various ways. Points can be obtained in a number of categories such as: when protecting or restoring habitats, reducing the Heat Island Effect, or even maximizing open space. Using organic substances such as grass or gravel will also gain more LEED Points.

Calculate LEED Points

Learning how to calculate LEED Points is a fairly easy practice that you can begin employing today. For example, let’s take a Site that installs a Porous Paving Fire Lane with native grasses in order to restore a natural habitat, and a grass overflow parking lot to maximize the open space. These changes would count towards 2 LEED Points.

This particular Site’s two installations would also happen to count towards Stormwater Design – Quality Control which counts as 1 point, Stormwater Design – Quantity Control which contributes 1 more point, and Heat Island Effect – Non-Roof which is an additional point as well. For those keeping track, that means with just these qualifications this Site is eligible for a minimum of 5 LEED Points after just two installations. Depending on manufacturers materials and materials used in the process of the installation – there is the possibility to gain additional points as well.

Are Permeable Pavers Right For You?

As the world of green building evolves, we will continue to focus our efforts on creating a more environmentally conscious landscape. Building, construction, and landscaping will begin to include Porous Paving as a means of surface pavements over traditional hard surface structures more and more. If creating a durable, cost-effective, and flood protected surface for your next project are all important factors, then choosing a Permeable Paving solution is a smart choice. Invisible Structures provides the highest quality of Permeable Pavers along with professional service making it an easy choice to switch for your next project. Dedicated to offering Green Solutions, Invisible Structures is the industry’s top choice for porous paving. We are committed to maintaining the highest quality– in sustainability and aesthetics.

About Us

Invisible Structures is the leader in porous paving and stormwater management solutions. We provide the finest in grass porous paving, gravel porous paving, underground stormwater storage, erosion control, drainage, and access mats.

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Permeable and Porous Paving Products

Grasspave 2
Grasspave2 porous pavement system, reinforces the root system of grass for a drivable surface. Grasspave2 is the premier flexible grass permeable paver and is perfect for beautiful fire lanes, parking lots, access roads, low-use driveways, RV parking and more.

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Gravelpave 2
Containing gravel, remaining porous, reducing dust, and adding beauty to a site ar some of the benefits to Gravelpave2. Gravelpave2 pervious pavement system can withstand unlimited traffic volumes at low speed for use in Parking lots, trails, utility roads, driveways, and more.

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