Warm up to the opportunities presented by Radiant floor heating
by Susan Brimo-Cox
has been in use for some 2,000 years you’d be right in thinking that the originators might have had a pretty good idea. Of course, the technology of radiant heat has improved through the centuries. And, today, many people are giving radiant floor heating another look as an option in commercial and residential applications.
Radiant heat delivers warmth without ducts and registers; heats evenly, in an energy-efficient manner; and is silent. There are hydronic (hot water) and electric systems.
“A lot of smaller jobs [such as baths and kitchens] and retrofits are done with electric systems,” reports Hoyt Corbett, a consultant and publisher of The Radiant Flooring Guide,” based in Seattle. Electric systems are growing fast, especially in conjunction with tiled floors, as the electric elements can be embedded in the thinset layer, he adds.
 Most big projects are hydronic, Corbett says, because there is a better level of control with regard to water temperature and circulation. “In 2002, there was approximately 130 million square feet of [new construction] hydronic radiant flooring installed—and about half of that was installed in concrete slabs.”
And Corbett reports that the installation of radiant heat flooring is growing at about 20 percent to 25 percent a year. So, it makes sense, he observes, for concrete contractors to investigate and form a relationship with radiant heat installers in their area. “The fit is very good!”
Whether or not radiant floor heating presents an opportunity for concrete contractors depends on the area of the country you’re in and the usual method of construction there.
 Radiant floor heating is a natural in on-grade concrete slabs. The heating tubes are normally fastened with plastic ties to 6-inch by 6-inch concrete mesh so the tubing winds up in the middle of the slab. These slabs expand and contract more frequently than slabs without radiant heat, so all care of the normal steps should be taken with the pouring and curing. But hydronic tubing is very flexible, so some cracking should not be problematic, just cosmetic. Corbett explains that in Europe the systems are typically done in two pours, with the tubes embedded in a topping slab.
If radiant floor heating is to be installed without a slab on-grade or on the second floor — or higher — the standard installation involves attaching the tubing to the subfloor, and then, most frequently, a 11⁄2-inch slab of concrete or gypsum-based cement product is poured on top. (In some applications, the tubing is attached under the floor, between the floor joists, but that doesn’t really apply to this discussion.)
 The good news for concrete contractors is that concrete floors have the highest output of radiant heat, and the best heat retention. The cost to install radiant floor heating runs from about $3.50 to $14 a square foot, depending on where you are in the country and how elaborate the system, according to Corbett. And, he says, there is a shortage of installers.
“Today, radiant heat is the fastest growing segment of the heating industry,” said Mike Chiles, president and general manager of Watts Radiant, a leading supplier of radiant heat products. “We’re seeing an incredible rise in interest among those in the concrete industry — not just for the popular PEX tubing, but also for synthetic rubber tubing, and electric radiant mats in, and over concrete. Commercial hydronic installations are rising fast, both for large concrete floors and large snowmelt systems. We’re seeing a lot more of these with stamped concrete finishes.” |
