Warmboard-S vs gypsum concrete — a look at the differences

Warmboard, Inc.
Jul 25, 2017 · 4 min read

When it comes to radiant heating, these types of systems are like night and day. Let’s take a look at some of the differences.

This is how gypsum concrete is “installed”

Performance

Simply put, the job of a radiant system is to conduct heat from water in a tube to the interior of your home. Gypsum concrete is a poor conductor — absorbing heat like a sponge, before slowly releasing after several hours. Given a blank sheet of paper, no engineer would ever choose this method for a heating system. Comfort is like hunger — it should be fixed quickly. Gypsum concrete is much too slow to respond to your changing needs — too slow to heat up, too slow to cool down when you’re feeling too hot.

Warmboard’s simple, clean installation

Warmboard in contrast was designed to maximize conductivity, transferring the heat generated as quickly as possible into your home to ensure you are always comfortable. With Warmboard, floors are more evenly heated and your investment in fine flooring, from tile to wide plank hardwoods, is protected. Our high conductivity means more widely spaced tubing, which means fewer other components (and labor), and much lower water temperatures, which saves energy and extends the life of all equipment in your heating system.

The video below clearly show the difference in performance between Warmboard and gypsum concrete. With identical testing conditions, there’s just no contest between these two radiant products.

When it comes to installation, the differences are stark.

Gypsum concrete weighs 15 lbs per square foot dry (25 lbs wet). Because of this, structural changes must be engineered to accommodate the weight, including code enforcement and seismic considerations for certain parts of the country. Gypsum concrete takes many days to dry, and can even lead to potential mold issues if not dried adequately.

Because gypsum concrete is a poor conductor of heat, installers often double or triple the amount of tubing in order to improve output. While this does improve response times (as seen above), it also increases the amount of tubing required, the number of manifolds and the complexity of the control system — not to mention the additional labor.

For those installing hardwood, high mass systems will also require sleepers (not used in our videos). Sleepers are wooden 2x4s located every 12 inches within the concrete pour which allow the hardwood to be nailed down properly. These 2x4s break up the cement space and interrupt the transfer of heat across the surface. The result is much higher striping and much more noticeable temperature differences. And hardwood installation becomes extremely problematic and expensive. Sleepers are warped as the concrete dries creating an uneven surface to install the flooring. Increased striping can age the floor unevenly, causing warps and cracks. In stark contrast is Warmboard, which avoids all these hassles while simplifying the install process. Another option is to use one or two layers of plywood over the surface of the dried concrete. This eliminates the sleepers, but also dramatically inhibits heat transfer by adding over an inch of material between the heat source and the interior space. Compared to Warmboard-S, gypsum concrete also requires:

  • Additional subfloor installation
  • Increased amount of tubing, manifolds, controls and the labor to install them all
  • Sealant to protect porous gypsum concrete from damage
  • Addition of pressure treated bottom plate for all walls
  • Upsized floor joists for increased weight
  • Addition of nailing strips or floating plywood overlay in order to achieve nailed in place hardwood flooring
  • Vacation home may require remote communication system to heat home a day or more prior to your arrival
  • Higher water temperatures: 110–150ºF (43–65ºC) compared to 80–120ºF (26- 49ºC) with Warmboard-S

As you can see, the benefits of Warmboard are many. When you combine faster installations, better performance and greater energy savings, this decision to choose Warmboard is a no-brainer.

Warmboard, Inc.

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The premiere technology in radiant heat. The most energy efficient, fast response & comfortable hydronic heating system on the market. warmboard.com

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