ᐅ Cement screed without chemical additives does not properly dry.
Created on: 25 Nov 2025 13:00
B
BrnZck91
Hello everyone!
On September 3rd, we had 65mm (2.6 inches) of cement screed installed (without chemical additives).
The heating protocol was followed, and we ventilated the house three times daily for 10-20 minutes each time. Several calcium carbide (CM) measurements have already been taken, and even after following the heating schedule, we consistently maintained heating up to 30°C (86°F).
During this time, plasterers and painters were also present. However, that was almost three weeks ago now.
Tomorrow the screed will have been laid for 12 weeks, and the last CM measurement taken last Monday still showed 2.6%.
On the recommendation of the screed company, we have since increased the heating to 45-50°C (113-122°F) up to today and also set up a construction dryer and a smaller room dehumidifier. Someone from the screed company visited today and couldn’t explain the situation. Inside the house, there is no noticeable moisture. It does not smell damp. There is no condensation on the windows, and the humidity levels on three hygrometers placed throughout the house range between 35-44%.
Still, the electronic moisture meter shows values between 1.7 and 2.2, and when the meter is placed in the hole left by earlier CM measurements, it even rises up to 2.7. I am at a loss.
The screed installer contacted another floor installer who recommended lowering the heating to 25°C (77°F), so that the air temperature stabilizes around 20°C (68°F). The reasoning was that the devices do not work correctly at higher temperatures (currently the air temperature is over 35°C (95°F)). The electronic moisture meter even showed 3.0% on the concrete stairs, which seems unlikely. But the CM measurements were done by the tiler and flooring installer, often together using two different devices alternately.
We only have one more measuring point left, and the furniture is arriving on December 9th.
The flooring installer also suggested applying an epoxy resin coating to prevent moisture from rising. To allow space for any ascending moisture, he plans to leave out the baseboards for now. This is not possible in the bathrooms, of course, since there will be tiles on the floor and walls.
I really hope someone here can help. I am getting desperate.
On September 3rd, we had 65mm (2.6 inches) of cement screed installed (without chemical additives).
The heating protocol was followed, and we ventilated the house three times daily for 10-20 minutes each time. Several calcium carbide (CM) measurements have already been taken, and even after following the heating schedule, we consistently maintained heating up to 30°C (86°F).
During this time, plasterers and painters were also present. However, that was almost three weeks ago now.
Tomorrow the screed will have been laid for 12 weeks, and the last CM measurement taken last Monday still showed 2.6%.
On the recommendation of the screed company, we have since increased the heating to 45-50°C (113-122°F) up to today and also set up a construction dryer and a smaller room dehumidifier. Someone from the screed company visited today and couldn’t explain the situation. Inside the house, there is no noticeable moisture. It does not smell damp. There is no condensation on the windows, and the humidity levels on three hygrometers placed throughout the house range between 35-44%.
Still, the electronic moisture meter shows values between 1.7 and 2.2, and when the meter is placed in the hole left by earlier CM measurements, it even rises up to 2.7. I am at a loss.
The screed installer contacted another floor installer who recommended lowering the heating to 25°C (77°F), so that the air temperature stabilizes around 20°C (68°F). The reasoning was that the devices do not work correctly at higher temperatures (currently the air temperature is over 35°C (95°F)). The electronic moisture meter even showed 3.0% on the concrete stairs, which seems unlikely. But the CM measurements were done by the tiler and flooring installer, often together using two different devices alternately.
We only have one more measuring point left, and the furniture is arriving on December 9th.
The flooring installer also suggested applying an epoxy resin coating to prevent moisture from rising. To allow space for any ascending moisture, he plans to leave out the baseboards for now. This is not possible in the bathrooms, of course, since there will be tiles on the floor and walls.
I really hope someone here can help. I am getting desperate.
After 24 hours open: still dry and humidity below 65%. The spot is one meter (3 feet) away from today’s measurement point, which showed 2.2% CM (calcium chloride moisture content). I closed the spot again and now have the room window tilted open, while the heat pump is running again. Let’s see how it looks tomorrow.
