We realized after 12 days that our installer had set the wrong drying program. It has been running constantly at 30 degrees Celsius (86°F) for 12 days. This is an electrically powered external device, not the heat pump.
The installer is coming tomorrow. What do you recommend? I will have the screed moisture measured today. However, my main concern is the expansion. If I increase the temperature from 30 to 40 degrees Celsius (86 to 104°F) tomorrow, then from Friday to Saturday to 50 degrees Celsius (122°F), and keep it there for two days until Monday, will that be sufficient?
We have already scheduled all subsequent work steps with all contractors after the drying program. It would be a disaster if we had to extend the program.
The installer is coming tomorrow. What do you recommend? I will have the screed moisture measured today. However, my main concern is the expansion. If I increase the temperature from 30 to 40 degrees Celsius (86 to 104°F) tomorrow, then from Friday to Saturday to 50 degrees Celsius (122°F), and keep it there for two days until Monday, will that be sufficient?
We have already scheduled all subsequent work steps with all contractors after the drying program. It would be a disaster if we had to extend the program.
Vicky Pedia29 Jun 2020 23:20bauenmk2020 schrieb:
I read that heating the screed up to about 50°C (122°F) for the covering readiness also has the positive side effect of reducing energy costs in the next heating season. Is there any truth to this? Heating is purely functional and has nothing to do with covering readiness!!!
@ Oetzi: First of all, thank you for the kind words!
Regarding your questions:
“Heating screed and the heating program starts (...) only after nearly 5 weeks.”
Answer:
Basically, any screed will dry to a suitable level for covering after about 6 weeks, even without additional heating (in this case: underfloor heating with warm water), provided proper ventilation is ensured.
-----------------
“The screed is therefore already somewhat dried, but presumably still quite moist underneath.”
Answer:
“Slightly dried” is certainly an understatement.
Most likely, as the CM moisture measurement will reveal, the screed would be dry even without heating.
However,
functional heating to check the building components (the heating system parts) is essential.
---------------------
“I would now like to accelerate the drying process a bit and use condensation dehumidifiers. Is this safely possible during functional heating, or should the construction dryers be switched on only afterwards?”
Answer:
This is possible, but not always practical. Using condensation dehumidifiers should be considered carefully from an economic perspective! Please do not underestimate the energy costs involved.
Good ventilation with suitable outside humidity is usually sufficient, as long as outdoor humidity stays below 70%.
---------------------------
“And what humidity level should the construction dryers not go below to avoid surface curling?”
Answer:
Surface curling at screed edges can occur even with slow drying and is not a defect, but a material-specific characteristic of mineral-based screeds.
However, construction dryers should not reduce relative humidity below 35%, otherwise capillaries break, and the screed cannot dry further!
--------------------------
“Also, I would set up ordinary fans ...”
Answer:
That is the best solution! It is better to use several fans and keep windows open than to rely solely on forced drying.
------------------------
“Is that okay, or must I use the special fans rented with the dehumidifiers?”
Answer:
Fans with sufficient capacity to generate significant air movement are perfectly adequate!
------------
“For how long should construction dryers be used to get the building reasonably dry?”
Answer:
No concrete estimate is possible since a construction dryer removes moisture not only from the screed but also from the masonry.
-------------------------
Regards: KlaRa
Regarding your questions:
“Heating screed and the heating program starts (...) only after nearly 5 weeks.”
Answer:
Basically, any screed will dry to a suitable level for covering after about 6 weeks, even without additional heating (in this case: underfloor heating with warm water), provided proper ventilation is ensured.
-----------------
“The screed is therefore already somewhat dried, but presumably still quite moist underneath.”
Answer:
“Slightly dried” is certainly an understatement.
Most likely, as the CM moisture measurement will reveal, the screed would be dry even without heating.
However,
functional heating to check the building components (the heating system parts) is essential.
---------------------
“I would now like to accelerate the drying process a bit and use condensation dehumidifiers. Is this safely possible during functional heating, or should the construction dryers be switched on only afterwards?”
Answer:
This is possible, but not always practical. Using condensation dehumidifiers should be considered carefully from an economic perspective! Please do not underestimate the energy costs involved.
Good ventilation with suitable outside humidity is usually sufficient, as long as outdoor humidity stays below 70%.
---------------------------
“And what humidity level should the construction dryers not go below to avoid surface curling?”
Answer:
Surface curling at screed edges can occur even with slow drying and is not a defect, but a material-specific characteristic of mineral-based screeds.
However, construction dryers should not reduce relative humidity below 35%, otherwise capillaries break, and the screed cannot dry further!
--------------------------
“Also, I would set up ordinary fans ...”
Answer:
That is the best solution! It is better to use several fans and keep windows open than to rely solely on forced drying.
------------------------
“Is that okay, or must I use the special fans rented with the dehumidifiers?”
Answer:
Fans with sufficient capacity to generate significant air movement are perfectly adequate!
------------
“For how long should construction dryers be used to get the building reasonably dry?”
Answer:
No concrete estimate is possible since a construction dryer removes moisture not only from the screed but also from the masonry.
-------------------------
Regards: KlaRa
Ötzi Ötztaler3 Jul 2020 07:04
Dear @KlaRa,
Thank you very much for the detailed response! Due to the rather humid weather over the past few weeks, it is probably not completely dry yet.
Our masonry house was built at a rapid pace; earthworks started in March, and now at the beginning of July, the screed has been in place for more than a month. The construction didn’t have much time to dry out the masonry, so I want to be careful. I want to avoid mold or other problems in the long term.
I gather that at such a late stage, I don’t need to worry much about cracking caused by drafts anymore. That’s a positive sign. Some corners have already slightly lifted (the spirit level shows a small incline in each case), but hopefully, they will settle back down by the end of the drying process.
Thank you very much for the detailed response! Due to the rather humid weather over the past few weeks, it is probably not completely dry yet.
Our masonry house was built at a rapid pace; earthworks started in March, and now at the beginning of July, the screed has been in place for more than a month. The construction didn’t have much time to dry out the masonry, so I want to be careful. I want to avoid mold or other problems in the long term.
I gather that at such a late stage, I don’t need to worry much about cracking caused by drafts anymore. That’s a positive sign. Some corners have already slightly lifted (the spirit level shows a small incline in each case), but hopefully, they will settle back down by the end of the drying process.
bauenmk20204 Jul 2020 09:37Vicky Pedia schrieb:
Also here: definitely a dryer, not a heater! It is very unfortunate that so many issues are mixed up here. We had a mobiheat yellow unit, connected via heavy-duty power supply. It was installed on the supply and return lines of the underfloor heating system.
Vicky Pedia4 Jul 2020 11:20bauenmk2020 schrieb:
We had a mobiheat yellow device, connected via high-voltage power supply. It was installed on the supply and return lines of the underfloor heating.So, the unit heats the underfloor heating electrically because the heat pump isn’t running yet or something like that. Heating doesn’t necessarily mean drying, but of course, warmth also helps with drying.bauenmk20204 Jul 2020 11:52@Vicky Pedia
The heat pump hasn't been installed yet. They just ventilate the warm, humid air out. Would a dryer have been more effective?
The heat pump hasn't been installed yet. They just ventilate the warm, humid air out. Would a dryer have been more effective?
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