Microcement with underfloor heating: how to do it right
More and more customers are giving up traditional radiators and are opting for underfloor heating. Such a solution, although more expensive in the installation, provides better thermal comfort and is cheaper in use. However, not all finishing materials can be used for underfloor heating. For example, pay attention to large floor tiles and many types of wood. And what about the microcement with underfloor heating? The microcement can be used over underfloor heating, but several important rules must be observed.
1. Take into account the thickness of the microcement when designing the height of the screed
The microcement system has only 3mm and it should be remembered to use the right level of the screed, so that the total height of the floor with the microcement matches the floor height in the other rooms.
2. Heat up the floor
On floor heating, cement or anhydrite screed is usually laid. When the screed layer is bonded, turn on the underfloor heating to allow the water to evaporate from the screed. This should be done slowly, gradually raising the temperature by 5 ° C a day, up to a maximum temperature of 26 ° C, then it is recommended to keep the temperature at 24 ° C for about 2 weeks. Then gradually switch off the heating to cool down. The whole heating process takes about 3 weeks. Substrate humidity should not exceed 4%.
3. Prepare dilatation joints
The microcement itself does not require dilatation joints, however, care should be taken to prepare the dilatation joints which are located in the concrete screed. At the dilatation site, every 7-10 cm, we make transverse incisions with a length of 20 cm. Thus, something like the seam will form across the dilatation. Then we put reinforcing bars with a cross-section of 6 mm into the resulting cuts and fill the resulting gap with epoxy resin. If you do not want to perform the above treatments, you can always transfer the dilations to the microcement.
4. Use fiberglass mesh with bonding bridge
The use of fiberglass mesh will overcome the stresses and tension associated with the heating of the substrate and protect them from transferring to the microcement layer. The substrate should be sanded and vacuumed. Then first layer of bonding bridge can be applied. Fiberglass net should be immersed in the bonding bridge (reinforcement set available in our store). It is worth investing in a good quality mesh – the cheaper ones can be washed away. After 3-4 hours, apply the second layer of bonding bridge to obtain a smooth surface.
After the next 3-4 hours, gently sand the surface, remove the dust and apply the first layer of microcement.
When the layer has bonded, regrind it and apply the final layer of microcement.
During the work of applying the microcement under no circumstances should you turn on the heating, as it may cause microcracks on the surface of the microcement.
5. Apply two layers of varnish
The last stage is sealing. It should be done on the second day after application of the microcement at the earliest. Apply 2 layers of a dedicated microcement sealer. The time between one layer and the other should be at least 12 hours. Why do we recommend one coat of varnish for walls (except for wet rooms) and two coats for the floor? The floor is exposed to higher loads and damage, therefore, to be sure that it is thoroughly protected, we recommend two-coat sealing. With one layer, it may happen that some places have been inaccurately covered with sealer, with two we minimize this risk. It is worth mentioning that the best varnishes for microcement are polyurethane two-component varnishes (eg PU Fest 2K). They provide optimal strength, water and stain resistance, they spread easily, do not turn yellow, and do not leave marks on the roller.
The floor is ready for use after 7 days. Then you can turn on underfloor heating.
Frequently Asked Questions:
1. Can I use microcement on underfloor heating?
2. What is microcement thermal conductivity?
The microcement layer is very thin and the microcement itself conducts heat well.
3. Does the microcement break due to temperature changes?
No. Thanks to the use of a special blend of polymers, the microcement is flexible and does not crack, further microcement can be used for underfloor heating, in saunas or for finishing fireplaces.