The radiant heating system is an ideal way to warm up any space. It’s comfortable, quiet and energy efficient. Most of the installation process will involve laying out probes and tubing and connecting them to a boiler. But there is a way for you to do part of the work yourself and maybe get your plumber to knock a few bucks off the cost of the job. The trick is to use a special foam panel from Schluter systems called Bekotec.
Basically you lay the panels directly on the floor, press-fit the tubing into them, and cover them with a thin layer of specially-mixed concrete. It’s a lot less work than the traditional way of installing heavy metal mesh and tying tubing to it. Another great reason to use this system is to preserve as much headroom as possible, such as in a basement with a low ceiling.
The panels provide a thermal break, so you don’t have to add an extra layer of insulation. In fact, using this system, it’s less than one and three-quarters of an inch, plus concrete, versus about four inches for the old-school method. You want to mix with no aggregate as it’s just five parts sand to one part portland cement. Less concrete means less weight and that’s important if you’re going over a wood floor. It also means the slab will heat up more quickly so you can use lower water temperatures and save on your heating bill. Overall, it makes for a much more responsive system.
Before you start laying panels, grab a long leveler and check the floor to make sure it doesn’t pitch significantly or have high or low spots bigger than a quarter of an inch. You’ll see light peeking underneath as a sign of an uneven ground. Fill any big dips with leveling compound, and then once the floor is in good shape sweep it thoroughly and clean the base of the wall so it will accept adhesive.
Line the base of the wall with peel and stick foam so the concrete can expand and contract along the edges. Peel off the backing as you go and trim it down after the concrete goes in.
Be sure to go around the entire project area with the foam whether it’s one room or an entire basement. Now it’s time for the panels. There are dovetail joints along the edges that lock together. Each piece has two male edges and two female edges so they can click together in rows and columns. Take the first panel, find the corner of the two female edges, and place it in the far corner of the room. You can work off either one of those exposed male edges and start connecting the panels one after another.
When you reach the far wall, you’ll probably need to trim the last panel, as you want it touching the foam but not so tight that it buckles the entire row of panels. Measure the distance between the wall and the edge of the last panel at both ends (you can’t assume the wall is perfectly straight). Grab a fresh panel, flip it facedown, and transfer those marks to its back. Make sure you’re removing the female edge, and use a straight edge to connect the two marks. Trim the panel and fit it in place. Now go back and start the second row of panels. From this point you’ll need to connect at least two edges of each panel to its neighboring edges. Continue laying panels until the floor is completely covered.
Now for the tubing. If you know how to lay out the loops you could do the work yourself here, or you could hand the job over to your contractor. But the basic idea is to tighten up the spacing near the windows and doors (cold spots), and make sure each circuit is one big loop of tubing that starts and finishes at the boiler. The pucks, or studs, as Schluter calls them, are staggered to clamp the tubing in a straight line and they make it easy to set the spacing in six-, nine-, or twelve-inch rows.
The key is to make sure the tubing never makes a u-turn or a 90-degree turn around a single puck as that might kink the tubing. Instead, bend the tubing around at least two pucks to turn a corner. The tension in the tubing may lift up the panels in places, but don’t worry: the concrete will fix that.
It’s fine to walk on the panels, but try not to crush the pucks because it makes it harder to hold the tubing in place. If the tubing does pop out, just pin it down. Leave several extra feet of tubing at the ends to make the connections. Now your contractor will bring the tubing through the wall and hook it to a manifold that divides the water into zones. Once the tubing is all hooked up it’s a good idea to pressure test the system before pouring the concrete.
If the tubing does have a leak you definitely want to fix it before it gets buried. Once the concrete cures for a few days you can install a finished floor directly over it.