PEX Tubing Install Options
PEX Radiant Concrete Floors (Slab on Grade)
For concrete floors (slab on grade), the Radiant PEX tubing is attached to the reinforcing mesh or rebar with cable ties before the slab is poured. Another good option is to staple the Pex tubing to styrofoam insulation. This type of PEX Radiant Floor Heat System has a large mass.
With this type of radiant underfloor heating, the space can only change by the radiant floor about 1/2 a degree per hour. Typically the water temperature used in pex water line for this type of radiant floor is between 90° and 115° Fahrenheit. It is imperative that the surface temperature of any PEX Radiant floor stays below 85° or it becomes uncomfortable and unsafe
PEX in thin slab over wood framing
Simpler in new construction but you can install this type of radiant floor as a retrofit, the radiant PEX Pipe is installed over framed floors and covered with concrete or lightweight concrete. We like this type of pex radiant floor heating the best. Our Radiant Floor Heat System is easy to install and it provides a very even heat. Thin slab PEX radiant floors have a much quicker response time. With this type of radiant floor the space it is heating can be changed by the radiant floor as fast as 2 a degree per hour. Thin slab radiant floors have many floor covering options. (tile, stained concrete, wood using sleepers, carpet, etc.). Typically the water temperature used in this type of radiant floor – the pex water lines are between 90° and 125° Fahrenheit. A quick note: When installing this type of pex radiant floor heat you need to have a tension break between the concrete and the wood substrate to allow the concrete and the wood floor to expand and shrink at their own rates. We recommend using 6 mil. sheet plastic.
PEX Under Floor Systems with Heat Transfer Plates
In a typical remodeling project, the PEX radiant tubing is snapped into radiant heat transfer plates which radiate heat to the floor above. The radiant heat plates tend to make the floor above them have warm and warmer spots. Still very comfortable. The installation of PEX under floors has its drawbacks. PEX when heated expands 1.1 inch per. 10 feet with a 100° temperature rise. Typically the temperature for this type of installation is between 120° and 145° Fahrenheit. If not properly installed this PEX radiant floor can be quite noisy or if you get the wrong type of transfer plates for your pex underfloor heating system.
PEX Radiant Tubing Under Floor
In a typical remodeling project, the PEX radiant tubing is hung with hangers below the floor about 1 inch. This allows the PEX radiant tubing to slide a little and sag a little as it expands making for a quiet floor. The hot water running through the PEX Radiant Floor Heat System Tubing heats the air which in turn heats the floor above. A insulation with a reflective surface mounted facing up leaving a 3 to 4 inch air space to the bottom of the floor is required. The PEX Radiant Heat from this floor system is very even. The air in this space must be stagnant, meaning all penetrations must be caulked and the floor joists where they meet the band joist also. Typically the temperature for this type of PEX installation is between 120 deg. and 165 deg. Fahrenheit. We know of many houses using this method, new construction and existing, where tubing was hung 16 inches on center and the water temperature is run from 125 degrees to 180 degrees out of the boiler or with a mixing valve. This has kept houses at a comfortable range with efficiency and no noise. In warmer climates you can run with a cooler temperature, but all this depends on your house’s heat loss and other factors.
