Heating protocol: Guidelines for underfloor heating
This heating and cooling protocol should preferably be carried out several times before installing floor covering or finishing (synthetic flooring, tiles, flagstones, parquet, laminate, marmoleum, etc.).
In this heating and cooling protocol, underfloor heating refers to a hot water pipe that is incorporated into a floor. The floor must be at least 25 mm thick above that water pipe.
In screeds that incorporate underfloor heating, cracks may form due to thermal length changes. To minimize this risk, it is necessary to bring the underfloor heating up to temperature slowly and gradually. We recommend following the heating and cooling protocol below.
A heating and cooling protocol for underfloor heating is based on the water temperature of the heating system and not on any thermostat temperature in the room in question. It is advisable to continue the process until the water has reached a maximum temperature of 40 °C. As a general rule, the water should not exceed a maximum temperature of 40 °C. Installation companies often specify 55 °C as the maximum temperature. However, this significantly increases the risk of cracking and detachment. If it is not absolutely necessary to maintain 55 °C, it is recommended to set the heating protocol to 40 °C. Do not exceed 55 °C under any circumstances. This greatly increases the risk of damage! It is also important that the screed has reached its final strength. This means that cement-bound screeds should preferably not be heated within 28 days. For calcium sulfate-bound screeds, this can be done slightly earlier if necessary, depending on the mortar quality. This is because calcium sulfate has a higher internal flexural strength.
It is difficult to say how much earlier, as this depends entirely on the conditions under which the floor was dried. As a rule of thumb, the calcium sulfate floor should not contain more than 3% moisture by weight. This must be determined using a calcium carbide meter.
NB Cracks do not usually occur during the heating phase, but during the cooling phase. This phase is therefore even more important than the heating phase, so the correct speed must also be maintained during cooling.
Start with a water temperature that is 5°C higher than the ambient temperature of the room in question. The water temperature must be read on the heating system.
Increase the water temperature by 5 °C every 24 hours (or longer) until the practical maximum water temperature of 40 °C is reached (see comments above).
Keep the maximum water temperature stable at 40 °C for at least 24 hours.
Then lower the water temperature by 5 °C every 24 hours until the start temperature is reached again. It is becoming increasingly common for underfloor heating systems to also be able to cool. With such a system, it is important (especially in summer when temperatures are high) that the cooling cycle is continued until the minimum temperature on the heating and cooling unit reaches 15 °C.
If there is sufficient time available, repeat this cycle several times.
It is advisable to provide this heating/cooling protocol to the end user/consumer for normal use after completion. The heating and cooling protocol must also be followed after prolonged shutdown of the underfloor heating.
Heating protocol
Day 1
Water temperature 20 °C
Day 2
25 °C
Day 3
30 °C
Day 4
35 °C
Day 5
40 °C
Day 6
40 °C
Cooling protocol
Day 7
35 °C
Day 8
30 °C
Day 9
25 °C
Day 10
20 °C
Day 11
Repeat or terminate
Preferably restart the procedure and perform it several times. If this is not possible due to time constraints, then start using the installation.
N.B. This guideline is in accordance with BA guideline 2.1 of the Dutch Agricultural Marketing Board.