Hello,
about six weeks ago, the screed (anhydrite screed) was installed in our house, and the screed heating program has been running at 45°C (113°F) for one week now. Before we started heating the screed, the indoor humidity was always around 70%, with the rooms naturally being cold. After ventilating, it hardly dropped below 60%. Since turning on the heating, the room temperature has been about 27°C (81°F) and the humidity is between 24 and 30%. Why is the humidity so low now? I thought that due to the new build and the screed, there would still be liters of water inside the house, and the air should still be quite humid. Is it this dry because no one is living in the house yet, or because it is so warm inside? How was it for you?
Best regards,
Sabine
about six weeks ago, the screed (anhydrite screed) was installed in our house, and the screed heating program has been running at 45°C (113°F) for one week now. Before we started heating the screed, the indoor humidity was always around 70%, with the rooms naturally being cold. After ventilating, it hardly dropped below 60%. Since turning on the heating, the room temperature has been about 27°C (81°F) and the humidity is between 24 and 30%. Why is the humidity so low now? I thought that due to the new build and the screed, there would still be liters of water inside the house, and the air should still be quite humid. Is it this dry because no one is living in the house yet, or because it is so warm inside? How was it for you?
Best regards,
Sabine
A look at the Mollier diagram helps: assuming you had 18°C (64°F) and about 60% relative humidity, there were approximately 7 g/kg of water vapor in the air inside the house.
At 27°C (81°F) and 30% relative humidity, there are also around 7 g/kg.
Conclusion: the absolute humidity is roughly the same, even slightly drier, which makes sense when you are heating and ventilating.
The moisture in the building doesn’t flow out quickly through walls and floors; it’s a very slow process.
At 27°C (81°F) and 30% relative humidity, there are also around 7 g/kg.
Conclusion: the absolute humidity is roughly the same, even slightly drier, which makes sense when you are heating and ventilating.
The moisture in the building doesn’t flow out quickly through walls and floors; it’s a very slow process.
Thanks for the explanation. I had already read that during the screed drying process, the house would become so humid that water would run down the window panes, but that is not the case for us, so I was wondering about it. So, as the temperature inside the house drops, it will become more humid again. This morning it was only 24%.
Best regards,
Sabine
Best regards,
Sabine
During the first seven days, cement screed releases a significant amount of water. To prevent curling or cracking, the screed installers leave the house with all windows and doors completely closed and advise you not to change this for seven days. Do not walk on it, do not ventilate, do nothing. When you open the house after this period, it will be like a steam bath inside. It will be hot and completely humid. The fresh cement releases a lot of heat and moisture while curing. Now, however, open everything up and let fresh air in; otherwise, the plaster may start to detach from the walls.
Similar topics