Comparing Warmboard to Gypsum Concrete

Mon, 06/24/2013 - 10:57

The efficiency of Warmboard begins during installation and continues year after year by outperforming all other radiant systems. Warmboard’s thick aluminum surface conducts heat hundreds of times better than conventional or gypsum-based concretes. This superior conductivity also allows for faster response times, more even floor temperatures, and the ability to generate more heat from lower water temperatures.

Lower water temperatures allow for more flooring options. They also mean lower energy bills every month. A Warmboard system will seamlessly integrate with geothermal, solar and ground source heat pumps.

The following items are associated with gypsum concrete and do not apply to a Warmboard Installation

Subfloor Installation
Warmboard is a structural subfloor and can be installed on 12, 16, or 24 inch centers using 10D nails, #8 Ring Shank Nails, or deck screws.

Gypsum concrete
A gypsum-based product that is poured using hoses over existing subfloor immersing Pex tubing.

Gypsum concrete is porous and should be sealed
Cured gypsum concrete has air pockets that can substantially decrease its constitution. Gypsum concrete installers mandate that a special sealant is applied over the gypsum concrete to prevent deterioration

More Tubing and Manifolds
Unlike Warmboard’s tubing that is installed on 12" centers (Warmboard is at least 5x more conductive than gypsum concrete), expect 20-45% more tubing and manifolds (ports) since most gypsum concrete tubing is installed on 6" or 8" centers.

Additional pressure treated bottom plate for all interior, exterior walls
Since 1 ½" gypsum concrete is poured above the subfloor, an additional bottom wall plate is needed to maintain a drywall and baseboard nail area. If you are using carpet, ask a gypsum concrete installer how to install tack strips (do not nail tack strips into gypsum concrete as it will crack).

Upsized floor joists
Gypsum concrete is poured as a liquid. The installation weight is roughly 25 pounds per square foot. Once gypsum concrete dries, roughly 8 pounds per square foot of water (roughly a gallon) evaporates. The moisture evaporates into the home, the air, and the framing materials. The cured gypsum concrete weight is roughly 15-17 pounds per square foot (3x the weight of Warmboard). Gypsum concrete's floor joists upsizing will also greatly affect its material package cost.

Using real, nail down hardwood?
Gypsum concrete is fairly brittle and will crack and crumble if nailed into. Pressure treated 2x2 “sleepers” or flooring strips are required on 12" or 16" centers. If you install 500 square feet of hardwood, 25-35 “sleepers” will be needed, increasing labor and material costs.

Finished flooring contractors may be reluctant to install over gypsum concrete
Many architects specify a second layer of plywood be installed over the gypsum concrete. This is done to help level any inconsistencies from the gypsum concrete pour while providing a medium to make installing the finished flooring easier.

Vacation home?
With gypsum concrete, you may need to install a communications system to begin heating your home days prior to your arrival.

There is no doubt that gypsum concrete radiant systems are installed more frequently than Warmboard. However, over the last several years Warmboard has seen substantial increases in market share. Construction professionals have access to our superior customer support and service. From our easy to use panel and tubing plans to our on-site installation support; we want every project to receive exemplary results.

Also consider...
How even are these finished floor temperatures? Once dried, where has the water laden gypsum concrete evaporated to? Gypsum concrete tube spacing is random (obviously) unlike Warmboard’s pre formatted 12" channels.

After reviewing this information it is clear that Warmboard, compared to gypsum concrete, is more efficient from installation through daily operation. The superior conductivity of Warmboard outperforms gypsum concrete and results in faster response times, more even floor temps, and greater overall operating efficiency. To see a video that compares response times and BTU outputs click here.


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