Get the Facts!

Looking to expand your knowledge about permeable paving? Have some questions about paving Green? Look here first! We've compiled this list as the ultimate quick reference tool for our most frequently asked questions. Can't find what you're looking for here? We'd be happy to help! Contact us with your specific questions.

FREQUENTLY ASKED QUESTIONS FROM AROUND THE INDUSTRY

What are permeable pavers?

Where can permeable pavers be used, and for what applications?

What are the ecological benefits of using permeable pavers?

Are permeable paver systems more expensive than traditional pavers?

Are permeable pavers strong enough to handle heavy loads and large vehicles?

Do permeable pavers require a lot of maintenance?

What intensity and duration of storms can be managed?

How well does permeable pavement perform in freeze and thaw conditions?

Does a permeable paver surface conform to the Americans with Disabilities Act (ADA) requirements?

Is there any recycled content available in permeable paver materials?

Can these systems be manufactured within 500 miles of a proposed project site?

Do you have examples of projects that have been installed for a period of time?

What are permeable pavers?
Permeable pavers are made out of special materials that allow stormwater to filtrate through the surface and down into the ground beneath. Therefore, water is absorbed into the earth rather than flooding and contaminating our waterways with pollutants. This is unlike other conventional paving materials, on which water hits the surface and then naturally flows to the lowest point possible, which is normally a drain that then transports it - and the pollutants within it - to our waterways. Learn more about how permeable pavers work.

Where can permeable pavers be used, and for what applications?
Permeable pavers can be used for many commercial and residential applications. In fact, any area that requires a pavement surface could be designed with permeable pavers. They are commonly used for driveways, emergency access lanes, fire lanes, soil and land stabilization, public parks, parking lots and for landscaping purposes. However, specific applications and uses will vary depending on the material, design and system of the paver. Also, sites that are stormwater hotspots and have high exposure to toxic materials (e.g. scrap yards, fuel stations, etc.) would not be a good application for a permeable pavement system. Learn more about the different types of paving systems.

What are the ecological benefits of using permeable pavers?
Permeable pavers offer significant advantages to the earth. Because they allow stormwater to infiltrate back into the ground, permeable pavers significantly reduce stormwater runoff. This in turn reduces flooding and erosions, recharges the groundwater, reduces pollution, and improves water quality by providing a natural filtration system that also helps to preserve the quality of local waterways. For more ways that permeable pavers help create a valuable and sustainable solution for stormwater management, click here.

Are permeable paver systems more expensive than traditional pavers?
The cost for a permeable unit paver system is site specific and would need to be compared on a project basis. Typically, during the initial stages of development, permeable pavers do tend to incur a few more expenses than traditional types of pavers. However, lifecycle costs need to be considered when selecting a stormwater management system, as they have been proven to offer significant cost savings over a 30-year period. Learn more about the cost benefits of using permeable pavers.

Are permeable pavers strong enough to handle heavy loads and large vehicles?
Yes. Most permeable paving systems are designed to handle traffic and heavy vehicular loads. In fact, just like concrete or asphalt systems, permeable pavers can be designed to accommodate water wagons, fire trucks, garbage trucks, busses, etc. However, because the different permeable pavers vary by type, material and design, specific pavers are best suitable for certain applications. Learn more here.

Do permeable pavers require a lot of maintenance?
In order to get the best performance and drainage capacity from your pavers it is necessary to maintain them. The general requirements are that you sweep them once per year, vacuum sweep when clogging occurs as required, and re-fill in the voids when necessary. Learn more about permeable paver maintenance here.

Typically, normal BMP practices for parking lot and roadways would be used where street sweepers are employed to remove loose debris and silt build-up. Winter maintenance is actually reduced, where we have found that due to the excess amount of air in the void area of the aggregates, this space acts as an insulation barrier. Permeable pavement surfaces freeze at lower temperatures than asphalt and other impervious surfaces and will not trap water and slush on the surface during a 24-hour freeze-thaw cycle and will not require additional salting or plowing.

What intensity and duration of storms can be managed?
It depends on the amount of water that drains onto the paver, the depth (and storage capacity), the base, the infiltration rate of the soil under an open-graded base and the presence of drain pipes within an open-graded base. Permeable pavers are intended to manage water quantities and pollutants from smaller, more frequent storms such as those with a return period of 10 years or less. These storms tend to be shorter in duration and often have the highest concentrations of pollutants. Permeable pavers are not intended to control flooding from larger, infrequent rainstorms.

How well does permeable pavement perform in freeze and thaw conditions?
Permeable pavers have been in service for years in freezing climates and have performed adequately. Many projects throughout Canada, the northern U.S., the United Kingdom and Germany speak to the durability of these pavement systems in cold climates, and their ability to accept snowplows and salts without paver damage. In order to ensure high durability in freezing climates, the paving units should conform to the requirements of ASTM C 936 in the U.S. or CSA A231.2 in Canada. Both of these product standards include tests for freezethaw durability.

When the sun and temperature are right, ice and snow can melt and immediately soak into the pavement surface. Water does not collect on the surface and re-freeze. This reduces slipping hazards. However, sand should not be used for foot or tire traction on permeable pavement surfaces. Instead, deicing salts can be used. After plowing, melting of any remaining snow can occur if the temperature rises above freezing. This will help eliminate ice from forming and reduce salt contamination in groundwater. Water in the base typically should drain within 24 hours. It's unlikely that ice will form in the base within this time period should temperatures drop below freezing. If the water does freeze before draining, there is adequate space for the ice to expand within the open-graded base, thereby minimizing the risk of heaving. Should soil heaving occur, the pavement surface is flexible and should not be damaged from minor upward movement or from resettlement during a thaw.

Does a permeable paver surface conform to the Americans with Disabilities Act (ADA) requirements?
Yes. ADA Design Guidelines require that surfaces be firm, stable and slip resistant. Permeable paver designs can provide a firm and stable surface for visually impaired persons and those using wheeled mobility devices. If the openings in the surface are not desirable, solid units can be used in areas subject to disabled persons. Such areas might include designated spaces in parking lots.

ADA recommends that the static coefficient of friction for flat surfaces along accessible routes be 0.6 and 0.8 for ramps. ADA advisory material recommends various test methods to assess surface slip resistance. Permeable pavers meet slip ADA resistance requirements using test methods recommended in ADA advisory literature.

Is there any recycled content available in permeable paver materials?
Fly ash and slag is used in the production of the concrete pavers, which would be a LEED item. However, crusher run products from recycling facilities typically will not meet the quality of DOT specifications and also will not meet sieve analysis requirements.

Can these systems be manufactured within 500 miles of a proposed project site?
Yes. Find a Manufacturer closest to you that is experienced in providing permeable paving services. Plus, you can learn about what to look for and what to ask specifically for your project needs.

Do you have examples of projects that have been installed for a period of time?
Yes! Check out our Case Studies and Featured Projects to watch videos and read about successful projects from all around the country.