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Concrete driveways offer many advantages over asphalt, including greater durability, longer service life, and less maintenance. But in the winter, when temperatures plummet and the snow flies, concrete and asphalt surfaces have equal maintenance needs: Both require frequent shoveling and de-icing. Or do they?
Some homeowners and businesses are keeping their exterior concrete surfaces maintenance-free and safe year-round by installing heated driveways with ice and snow-melting systems. Not only do these in-slab snow-melting systems eliminate plowing, backbreaking shoveling, and icy spills, they prevent potential damage to the concrete caused by snow-removal equipment and corrosive de-icers.
Though contractors usually install these systems in new slabs before placing the concrete, the heating elements can also be retrofitted into existing slabs.
Snow-melting systems are popular for both commercial and residential use. Here are some common applications:
Generally, two types of snow-melting systems are available for use in exterior slabs on grade: hydronic and electric. Both rely on four key components to turn the entire slab surface into a radiant heat source.
The heating element in a hydronic system is a closed-loop tubing made of a flexible polymer (typically a cross-linked polyethylene) or a synthetic rubber that circulates a mixture of hot water and propylene glycol (antifreeze), much like the mixture used in a car radiator. The fluid is warmed to temperatures of 140 to 180 F to provide sufficient heat for snow melting.
The tubing ranges in diameter from 1/2 to 3/4 inch and is flexible enough to bend into various layout patterns. It’s also designed to have a long service life. The tubing resists chemicals and corrosion and does not become soft at high operating temperatures or brittle at low outdoor temperatures.
The heat source – typically a water heater or boiler – can be powered by any energy source that satisfies the systems Btu requirements, including natural gas, electricity, oil, wood, or even solar collectors. For residential and light commercial snow melting, we recommend providing about 100 to 150 Btu per square foot of slab surface. A circulating pump and supply-and-return manifolds installed in an easily accessible location transfer the water between the heat source and tubing.
Successful operation of a hydronic heating system depends on proper tube spacing and layout. Because the hot water gives off heat as it travels through the slab, manufacturers usually recommend laying the tubes in a spiral or serpentine pattern to help distribute the heat evenly. Tube spacing depends on several factors including the snow-melting rate desired, the amount of insulation used under the slab, and the anticipated rate of heat loss. A typical spacing for an exterior slab on grade is 6 inches on center, which conveniently corresponds with the 6-inch grid pattern of welded wire reinforcing, but closer spacings may be needed in some applications.
Instead of hot water, electric systems use hot wires to heat pavement surfaces. The wires are surrounded by layers of insulation, copper grounding braid, and a protective outer jacket of PVC or polyolefin to form a flexible cable about 1/8 to 1/4 inch in diameter. The cable can be cut to length or spliced on the jobsite to suit various layouts.
To simplify installation, presized mats with the cables already embedded in them also are available. Some manufacturers can customize the mats for specific applications.
To melt snow efficiently, the cable should deliver about 36 to 50 watts of heating power per square foot of slab surface. Depending on the dimensions of the area to be heated, homeowners may need to upgrade their circuit panel or install a separate circuit to supply enough power.
Pro Climate typically spaces the cables 3 to 5 inches on center, which will melt 2 to 4 inches of snow per hour. For uniform heating, the cables should be arranged in a serpentine pattern running across the shortest dimension of the slab. Though the electric cable is buried in the concrete, both ends of the cable terminate in an above-ground weatherproof junction box for easy access.
Since 2015, Pro Climate Heating & cooling has taken pride in providing the Greater Toronto Area with superior, honest and reliable Heating and Air Conditioning services.
Pro climate is dedicated to its founding principle – building relationships based upon mutual trust and respect.
info@proclimate.ca
888-905-8008
