Project Profile:
Heated Permeable Pavers

In colder climates, it’s not uncommon for driveways, walkways or patios to be installed with either a heated pavement system or a permeable pavement system to help control ice buildup. This homeowner, however, chose to combine the two systems into one to create the ultimate ice-management pavement system.

The heated permeable paver driveway immediately melts and drains snow and ice. A heating coil is hidden beneath Belgard Eco-Dublin® permeable pavers, which are laid at a 45-degree angle to the house to add visual interest to the elegant design. Decorative poured concrete curbing coordinates with the charcoal paver accents and sits atop edge restraints, adding both stability and a finished look to the pavement system. Matching curbing also lines the landscape beds throughout the property.

Benefits of a Combined Heated/Permeable Pavement System

With a heated pavement system, snow and ice melt immediately to prevent accumulation, but if the surface is not graded properly, or if the pavement settles or degrades over time, there can be pooling or other issues. In comparison, a permeable system allows melting snow to drain into the joints and down into the subsurface rather than remaining on the surface and refreezing into ice. Typically, a plow clears the bulk of the snow, ice melt is applied, and the water goes away. However, with a combined heated permeable pavement system, no plowing or ice melt is needed. All snow or freezing rain that hits the surface melts and drains immediately. Plus, concrete pavers are more durable than poured concrete or asphalt, ensuring increased longevity of a properly working system. After two winters, the homeowners report that the system is performing beautifully, with no water or snow accumulation whatsoever.

How Does It Work?

Heating cables are laid out in the bedding layer, beneath the pavers. Two heat/moisture sensors, each about the size of a tennis ball, are installed in the pavement to automatically turn the heating cables on when there is both precipitation and a below-freezing temperature. When the system is on, it takes a lot of electricity to heat the 4,300 SF drive and walkway, necessitating the addition of a 400-amp pedestal to operate the system. However, because the sensors require both moisture and freezing temperatures, the system is rarely on.

A layer of sand prevents the pavers from having direct contact with the heating cable, which is laid out in the bedding layer. With direct contact, potential movement by the pavers over time could wear through the cable’s protective coating and short out the entire installation. This is especially important in a vehicular application.

Installing the System

Although, the system was planned to include only 18” of excavation, abnormal site conditions required 36” of excavation. A variable base of aggregate was then installed – 27” of #2 stone, 4” of #57, and 2” of #9. A heating cable was installed within the #9 stone layer. In order to maximize the amount of heat transferred from the heating cable to the pavers, the stone separating the cable and pavers needs as much contact with both as possible. Crushed stone with fines transfers the most heat, but doesn’t drain, so it isn’t used in a permeable installation. Instead, the heating cable manufacturer, Warmzone Radiant, recommended smaller drainage stone (#9) because it has more contact with the cable and transfers more heat than larger stone. A layer of sand was then installed over the aggregate to create a cushion between the heating cable and the pavers. This was done to prevent potential paver movement from wearing through the cable’s protective coating over time, which could short out the entire system. The crew also took extra care during the handling and installation of the cable to safeguard the protective coating and ensure long-term functionality of the system.

walkway

A heated permeable paver walkway coordinates with the driveway to create a dramatic entrance to the front of the home. The heated Eco-Dublin pavers provide a safe environment for guests and eliminate the need for snow shoveling and deicing agents.

2014 HNA Project Award Winner – Residential Concrete Permeable Pavers

Design/build Contractor: Grindstone Hardscapes, Josh & Kristen Graczyk, Owners
Location: Grand Island, Nebraska

 

Permeable Paver Driveways: Beautiful in Form and Function

Pavers: Eco Dublin®

The use of permeable pavers in driveway construction is growing exponentially across the country, particularly in areas with water use restrictions or strict stormwater management guidelines. Not only do permeable pavers boost your curb appeal, they also positively impact the environment by decreasing stormwater runoff and improving the water quality of local waterways.

Pavers: Aqualine™ Series

How, you ask? It’s ingeniously simple, actually. Permeable pavers are installed over a gradient bed of aggregate, with tiny aggregate filling the joints between each paver. As rainwater falls onto the pavers (or drains onto the pavers from another surface), the water percolates through the paver joints and down through the base materials below. There, the water is filtered by the aggregates, removing a number of pollutants before the water makes it’s way into the groundwater supply or returns to local waterways. The rising trend is to incorporate an underground cistern with a pump under the paver system so that the filtered water can be captured and recycled. A number of states and municipalities offer grants or tax incentives for these types of rainwater harvesting systems. The recycled water can be used for irrigation, water features, or other greywater uses.

Subterra Stone® improved the safety of this steep driveway.

Constructing a driveway with permeable pavers can also provide a number of other solutions for homeowners. For example, for steep driveways, permeable paver construction is safer during rainy weather conditions than traditional impervious surfaces, such as concrete or asphalt, because rain can permeate through pavers instead of pooling on the surface, thus improving traction.

Illustration of heated paver installation.

In areas prone to heavy snow, a heating system can also be installed under the sand base of the pavers so that snow or icy rain immediately melts and drains away, eliminating snow shoveling or ice accumulation. The sand acts as a buffer between the pavers and the coils, preventing damage from any shifting caused by automotive traffic.