Hello everyone,
I wanted to share an update on how the drying process of our house is going.
We felt that we had already ventilated a lot of moisture out during construction (we were a bit fanatical about airing out—even at 11 p.m. sometimes); however, it turns out that was far from enough when we recently cleared out the storage room under the stairs. In one corner, there was a wooden mirror that had absorbed water very thoroughly (in a good way, because it didn’t start rotting or molding, it was just very damp). Once the space under the stairs was empty, we went inside and noticed that the room was somewhat cooler and, above all, felt quite humid. It is now open, empty, and being ventilated. No mold has developed, but I imagine it might have looked different if we had parquet flooring and gypsum plaster.
Besides that, we measure the humidity in the bedroom, where it usually drops to around 49% during the day and then rises to 55% at night—I’m not sure if this is due to residual moisture or just the occupants. (We always set the ventilation system to a lower level at night.)
We also had another moisture issue with the bathroom exhaust on the upper floor. This wasn’t really thought through well and had little to do with construction moisture—but maybe it helps someone planning something similar. Our bathroom exhaust pipe runs through the unheated attic, makes a bend, and has a pipe splitter: one outlet leading upward and one downward into a “condensate trap.” The problem was that, due to freezing temperatures, the trap filled up quickly and then water ran back down the pipe—onto the closing cover of the exhaust fan. Since it was closed, the water leaked a bit onto the drywall… which, of course, swelled somewhat and caused the paint to peel. This will be fixed, of course. The condensate trap was emptied, and the pipe is now thoroughly insulated up to the roof outlet. Hopefully, it works better now.
I wanted to share an update on how the drying process of our house is going.
We felt that we had already ventilated a lot of moisture out during construction (we were a bit fanatical about airing out—even at 11 p.m. sometimes); however, it turns out that was far from enough when we recently cleared out the storage room under the stairs. In one corner, there was a wooden mirror that had absorbed water very thoroughly (in a good way, because it didn’t start rotting or molding, it was just very damp). Once the space under the stairs was empty, we went inside and noticed that the room was somewhat cooler and, above all, felt quite humid. It is now open, empty, and being ventilated. No mold has developed, but I imagine it might have looked different if we had parquet flooring and gypsum plaster.
Besides that, we measure the humidity in the bedroom, where it usually drops to around 49% during the day and then rises to 55% at night—I’m not sure if this is due to residual moisture or just the occupants. (We always set the ventilation system to a lower level at night.)
We also had another moisture issue with the bathroom exhaust on the upper floor. This wasn’t really thought through well and had little to do with construction moisture—but maybe it helps someone planning something similar. Our bathroom exhaust pipe runs through the unheated attic, makes a bend, and has a pipe splitter: one outlet leading upward and one downward into a “condensate trap.” The problem was that, due to freezing temperatures, the trap filled up quickly and then water ran back down the pipe—onto the closing cover of the exhaust fan. Since it was closed, the water leaked a bit onto the drywall… which, of course, swelled somewhat and caused the paint to peel. This will be fixed, of course. The condensate trap was emptied, and the pipe is now thoroughly insulated up to the roof outlet. Hopefully, it works better now.
Hello,
I want to contribute to this thread because I spent a long time searching online about construction moisture but hardly found any useful information. Maybe this can help other homebuilders!
Solid house with brick facade
KfW40 standard
Construction period: 5 months (early March to late July 2015)
Heat pump with integrated central ventilation system with heat recovery, underfloor heating
During the construction phase, we also meticulously ventilated daily by fully opening windows to release as much moisture as possible.
After moving in, we continued to ventilate 2-3 times a day for 5 months. Additionally, the ventilation system runs at level 2 (out of 3) during the day and level 1 at night.
Since the beginning of this year, we rarely ventilate manually besides the ventilation system, as the humidity has steadily decreased.
We placed hygrometers in several rooms to monitor humidity and ventilate manually if needed, but mostly the air is on the dry side rather than humid.
About 7.5 months after moving in, the humidity is usually around 35-45% depending on the weather.
As with BeHaElJa, our storage room is also the most humid space.
It is located under the concrete staircase and has neither windows nor a connection to the ventilation system.
For this reason, we had two ventilation grilles installed in the door and placed a dehumidifier in the room. Fortunately, the humidity there is slowly dropping as well, usually around 50-55%.
It still feels noticeably more humid than the other rooms, but thankfully there is no mold or anything like that.
We are very satisfied with the progress and are happy that our house has no mold issues. We are glad we chose the ventilation system since we don’t have time to manually ventilate several times a day due to work.
By the way, the only rooms we still ventilate manually are:
- The bathroom after showering
- The utility room when more than one load of laundry is drying there
- The kitchen when there’s been heavy cooking
I hope posts like this can be helpful to other home builders.
Best regards,
Teyla
I want to contribute to this thread because I spent a long time searching online about construction moisture but hardly found any useful information. Maybe this can help other homebuilders!
Solid house with brick facade
KfW40 standard
Construction period: 5 months (early March to late July 2015)
Heat pump with integrated central ventilation system with heat recovery, underfloor heating
During the construction phase, we also meticulously ventilated daily by fully opening windows to release as much moisture as possible.
After moving in, we continued to ventilate 2-3 times a day for 5 months. Additionally, the ventilation system runs at level 2 (out of 3) during the day and level 1 at night.
Since the beginning of this year, we rarely ventilate manually besides the ventilation system, as the humidity has steadily decreased.
We placed hygrometers in several rooms to monitor humidity and ventilate manually if needed, but mostly the air is on the dry side rather than humid.
About 7.5 months after moving in, the humidity is usually around 35-45% depending on the weather.
As with BeHaElJa, our storage room is also the most humid space.
It is located under the concrete staircase and has neither windows nor a connection to the ventilation system.
For this reason, we had two ventilation grilles installed in the door and placed a dehumidifier in the room. Fortunately, the humidity there is slowly dropping as well, usually around 50-55%.
It still feels noticeably more humid than the other rooms, but thankfully there is no mold or anything like that.
We are very satisfied with the progress and are happy that our house has no mold issues. We are glad we chose the ventilation system since we don’t have time to manually ventilate several times a day due to work.
By the way, the only rooms we still ventilate manually are:
- The bathroom after showering
- The utility room when more than one load of laundry is drying there
- The kitchen when there’s been heavy cooking
I hope posts like this can be helpful to other home builders.
Best regards,
Teyla
S
Sebastian7921 Mar 2016 11:17I am currently running the ventilation system during the screed drying process and almost no longer ventilate manually.
Contrary to the concerns I was initially told about, hardly any dirt reaches the top of the ventilation unit—only the pre-filters in the exhaust rooms need cleaning more frequently.
We have no condensation on the windows, and the substrate is sufficiently dry on both the ground floor and upper floor—without accelerators and after 12 days of screed drying. However, I am still cautious, as the screed is supposed to cool down first...
Nevertheless, I have acquired a total of four dehumidifiers, which are used temporarily, for example, after painting.
I’m curious about how much moisture will remain by the time we move in. Construction time so far: 11 months, and we still don’t have any floor coverings.
Contrary to the concerns I was initially told about, hardly any dirt reaches the top of the ventilation unit—only the pre-filters in the exhaust rooms need cleaning more frequently.
We have no condensation on the windows, and the substrate is sufficiently dry on both the ground floor and upper floor—without accelerators and after 12 days of screed drying. However, I am still cautious, as the screed is supposed to cool down first...
Nevertheless, I have acquired a total of four dehumidifiers, which are used temporarily, for example, after painting.
I’m curious about how much moisture will remain by the time we move in. Construction time so far: 11 months, and we still don’t have any floor coverings.
g
That’s quite a long time...
Regarding the moisture issue: heating and ventilation!
That’s the only way... without heating, moisture simply condenses in the coldest spots, such as your storage rooms... warm air needs to get in to carry the moisture away... otherwise it won’t work...
Sebastian79 schrieb:
I’m curious how much moisture will be left by the time we move in. Construction time so far: 11 months and we still don’t have any floor coverings .
That’s quite a long time...
Regarding the moisture issue: heating and ventilation!
That’s the only way... without heating, moisture simply condenses in the coldest spots, such as your storage rooms... warm air needs to get in to carry the moisture away... otherwise it won’t work...
S
Sebastian7921 Mar 2016 12:03No, not long at all – completely normal with a lot of reinforcement. And it's actually beneficial for the construction...
Hello
Based on my own professional experience and that of my brother, who specializes in leak detection and building drying, I would always recommend using technical drying in a solidly built house, especially during winter. The costs are low compared to the potential damage.
Olli
Based on my own professional experience and that of my brother, who specializes in leak detection and building drying, I would always recommend using technical drying in a solidly built house, especially during winter. The costs are low compared to the potential damage.
Olli
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