under-floor heating

  General guidelines under-floor heating:

  • The under-floor heating system should be installed according to the instructions of the supplier. An incorrectly installed under-floor heating system can cause the screed to become unfastened or the floor covering to lose shape.
  • Damage to the floor or the under-floor heating pipes resulting from incorrect installation and causing the finish layers to show incomplete covering, is beyond the liability of the installer of the floor and his suppliers.
  • After the application of the screed, wait for a minimum of 28 days, then gradually heat up the under-floor heating system by a maximum of 5° C per day.
  • Next, make sure the under-floor heating system is switched on uninterruptedly for a period of 14 days, so that the floor can set and any residual moisture can quickly evaporate.
  • Switch off the heating system at least 24 hours prior to levelling/applying floor covering.
  • Switch on the heating system at least 24 hours after levelling/applying floor covering and gradually raise the water temperature by a maximum of 5° C per day.

 

Concrete Core Activation
The above guidelines equally apply if a concrete core activation (CCA) system has been installed in the floor construction and outdoor temperature-dependent temperature control is used. In this case, the temperature will vary from 17° to 28° C. Another system often used is based on a constant temperature of 22° C.
If the floors to be covered have been installed with this system, no further precautions will be needed.

 

CCA
CCC is an abbreviation of concrete core activation, an innovative climate control system used to heat and cool corporate buildings. Flexible pipes are placed at the heart of the concrete flooring and water is pumped through the pipes at a constant temperature. The energy is largely derived from the ground. During the summer, relatively cool ground water is pumped through the pipes and/or to the air treatment installation, heated up by the warmer floor and returned to the ground at another place. During winter, the water is pumped back up again, heated by a heat pump and sent through the pipes at a higher temperature to heat the building.


The EN12667:2001 norm is used for our TFD floors
For 2mm, the value is 0,021 m2 K/W.
For 3mm, the value is 0,041 m2 K/W.
For MAG, the value is 0,04 m2 K/W.
For Click, the value is 0,033 m2 K/W.

Heating and cooling protocol
This heating and cooling protocol should, preferably, be followed through several times before a floor covering or finish is applied (synthetic floor, tiles, flagstones, parquet, laminate, marmoleum etc.).
In this heating and cooling protocol, under-floor heating is seen as a hot water pipe (system) installed in a floor. The floor above the pipe must be at least 25 mm thick.
Screeds in which an under-floor heating system has been installed can tear as a result of thermal changes in length. In order to minimize this risk, it is necessary to heat up the system at a slow, regular pace. It is advisable to use the heating and cooling protocol below for this purpose.
A heating and cooling protocol for under-floor heating is based on the temperature of the water in the heating system and not the thermostat temperature in the room. It is sensible to continue the process until the water has reached a temperature of 40 °C at the highest. Generally speaking, the water temperature should not exceed a maximum of 40 °C. Many installers suggest 55 °C as a maximum temperature, however, this considerably raises the risk of tearing and unfastening. If it is not absolutely necessary to stick to 55 °C, adapting the heating protocol to a 40 °C limit is recommended. Certainly do not go beyond 55 °C, as this will vastly increase the risk of damage! What is also important is that the screed has roughly reached its final strength. This means that cement-based screeds, preferably, should not to be heated up until at least 28 days after they have been installed. Calcium sulphate-based screeds, depending on the quality of the mortar, can be heated up slightly sooner, as calcium sulphate has a higher internal flexural strength. How much sooner is difficult to say, as this depends entirely on the circumstances in which the floor has been left to dry. As a general rule of thumb, a calcium sulphate floor should not contain a moisture weight percentage of more than 3 %. This should be measured with a carbide-method hygrometer.

Note
Most tears do not occur during heating, but during cooling. This means the cooling phase is, in fact, even more important than the heating phase and it is vital to maintain the proper pace during cooling.

  • Start with a water temperature 5 °C above ambient temperature. The water temperature should be taken from the heating system.
  • Raise the water temperature every 24 hours (or longer) by 5 °C, until the rough maximum water temperature of 40 °C has been reached (see earlier comments on this).
  • Maintain a steady maximum water temperature of 40 °C for at least 24 hours.
  • Next, reduce the water temperature every 24 hours by 5 °C until the original temperature has been reached. More and more under-floor heating systems also offer cooling. For these systems, it is vital (especially during the summer, when temperatures are high) that the cooling cycle is continued until the minimum temperature of the heating and cooling unit is down to 15 °C.
  • If time allows, repeat this cycle several times.
  • It is advisable to give the end user / consumer a copy of the heating and cooling protocol so as to ensure normal usage after delivery – as the protocol must also be followed whenever the under-floor heating system has been deactivated for a long time.