Because Warmboard-S is structural and part of conventional framing, most framing details and structural considerations are identical to structures built without radiant. Warmboard is only a pound per square foot heavier than 3/4″ subfloor which means virtually no change in structural design. Warmboard-S consists four modular panel types to create an infinite variety of radiant tubing layouts.

The dominant framing system in the US is Western Platform Framing. Plywood subfloor is typically the “platform” of that system. Warmboard-S offers a 1 1/8″ radiant panel and structural subfloor all-in-one which replaces the conventional plywood subfloor becoming, itself, the structural platform of your framing system. It is rated to carry all of the point loads, uniform loads and horizontal shear loads typically carried by 3/4″ subfloor. (Review ICC-ES report). It is ideal for 16″ or 24″ on center joists. It also works with 19.2 joist centers but this is not an optimum spacing due to increased waste factors. It is a particularly stiff and strong subfloor and will deliver a more solid feeling floor for your clients.

A Few Words on Slab: Thin slabs poured on subfloor add between 15 and 25 pounds per square foot of dead load. This is approximately ten tons when added to just 1000 square feet of floor area. In most cases this means upsizing joists to the next 2″ increment. Supporting beams go up in size as well. And if you are in a seismic zone, the lateral loads caused by slabs on second stories can be enormous, necessitating special engineering along with associated increase in construction cost. Upsized joists plus the thickness of the slab can add about 3″ per story to the overall height of the structure. In areas with critical zoning code restrictions on height, this can cause a problem. Even where it is not a zoning issue, height variations require extra sills under all walls at minimum. In many cases special details are required at transitions from hardwood areas or at staircases. Construction details for hardwood installations over slabs are particularly difficult to get right. There are numerous moisture control and fastening issues, which must be mitigated. Warmboard however, is a dry wood panel, which has an ideal thickness for nailing hardwood in place. No special details are required. Click here to see a sample set of Warmboard plans.

Because of its dual nature, it is essential that Warmboard-S be integrated into the construction documents to ensure best use practices. Inclusion in the construction documents will also ensure consistent bidding and cost-effective installation by bidding contractors. Follow these easy steps to include Warmboard into the Design process:

  • When it is determined that the Warmboard-S or Warmboard-R panel is the appropriate solution for your client’s project, contact the Warmboard Regional Manager (RM) for your area. If you do not have his/her contact data please call 877-338-5493.
  • If structural plans are not yet complete, the RM will consult with the structural engineer to optimize the floor framing plan to most efficiently integrate Warmboard. In most cases, Warmboard integrates seamlessly with conventional structural design and framing practices. Once completed, preliminary plans are sent to us, preferably in an AutoCAD format.
  • The RM will consult with you regarding zoning preferences, floor covering selections and other data necessary for proper design.
  • The Warmboard design team will produce a preliminary design for review and markup. Our documents will include panel and tubing layouts, manifold locations and various detail drawings and notes. These documents should be thoroughly reviewed to ensure that they meet your client’s needs. We provide one revision based on your markup at no cost.
  • Our design team will provide a final set of documents, including corrections based on your markup for inclusion into your full set of construction documents. These documents are typically 1/4″ scale plans formatted for D-sized sheets. If you would like a different sheet size or scale, simply let your RM know your requirements and we will accommodate them. We can supply plans in the AutoCAD file format, or plot them on bond paper or vellum per your request.

When considered solely as an individual element, Warmboard is not inexpensive. However, when viewed as part of a complete radiant system, Warmboard proves it’s value. Financially speaking, Warmboard is extremely competitive with systems that simply do not perform nearly as well. Additionally, here are some other points to consider:

  • Warmboard’s 12” on-center tubing spacing outperforms all other panels, even those using 6″ on center tubing. This spacing also results in lower material and labor costs, as well as other hidden expenses.
  • Warmboard’s patented design allows most installations to operate with water temperatures well below 120° F. Low water temperatures give you the option of using condensing boilers, solar, low cost, dedicated, conventional water heaters or even ultra high-efficiency ground source heat pumps. Lower water temperatures also allows for more flooring options.
  • Radiant heating cuts average energy use as much as 20% over forced-air systems, and the low water temperatures typical of Warmboard installations cut energy bills even more (View a technical water temperature chart).
  • Warmboard systems are easily zoned, further reducing energy usage by heating only the desired rooms or regions. Fast response means you won’t wait a long time to heat up that guest room when it is unexpectedly needed.
  • Radiant heating is ideal for cathedral and open beamed ceilings because energy is not wasted heating high spaces.
  • "High Velocity" air conditioning is a perfect match with a Warmboard Radiant System.