During an inspection, microbial growth has been discovered on the underside of the roof and in the basement floor construction.
From what I understand, you can address attic moisture by installing better ventilation (currently, it is self-ventilating). What surprises me a bit is that the only bathroom is in the basement; can moisture from the basement rise all the way to the attic? Or could moisture come from somewhere else (there is a toilet on the upper floor)? The measured moisture content is 9.5%; is this a lot or a little?
The inspector has also drilled a hole in the basement floor where "high moisture values" and "microbial odor" were found. The house needs to be re-drained; can this solve the problem with the moisture in the bottom slab or could it be suspected to be more serious than that? Could it mean that the entire basement floor has to be torn up?
From what I understand, you can address attic moisture by installing better ventilation (currently, it is self-ventilating). What surprises me a bit is that the only bathroom is in the basement; can moisture from the basement rise all the way to the attic? Or could moisture come from somewhere else (there is a toilet on the upper floor)? The measured moisture content is 9.5%; is this a lot or a little?
The inspector has also drilled a hole in the basement floor where "high moisture values" and "microbial odor" were found. The house needs to be re-drained; can this solve the problem with the moisture in the bottom slab or could it be suspected to be more serious than that? Could it mean that the entire basement floor has to be torn up?
When we bought our house, there was microbial growth on the inside of the roof sheathing, just like in "your" house. According to the inspector, this could be solved with better ventilation.
I crawled around a bit and checked, and it turned out that when the previous owner added insulation, he covered up 90% of the air vents, so there was no proper airflow. Pulled back the insulation a little, and today it's a completely different situation.
They always mention microbial odor no matter what the basement issue is. It's a kind of disclaimer in case there is a problem down the road. Regarding his drill holes, we had the same problem there. We don't seem to have a drainage problem, but probably the studs in the recreational room are directly on the concrete, so the moisture gets absorbed no matter what, and it starts to mold, etc. A dehumidifier solved the odor problem, and we use pellet stoves instead of relying on the electric heater, improving the basement climate.
However, we plan to tear out the entire recreational room once we redo the drainage to eliminate the symptoms.
I crawled around a bit and checked, and it turned out that when the previous owner added insulation, he covered up 90% of the air vents, so there was no proper airflow. Pulled back the insulation a little, and today it's a completely different situation.
They always mention microbial odor no matter what the basement issue is. It's a kind of disclaimer in case there is a problem down the road. Regarding his drill holes, we had the same problem there. We don't seem to have a drainage problem, but probably the studs in the recreational room are directly on the concrete, so the moisture gets absorbed no matter what, and it starts to mold, etc. A dehumidifier solved the odor problem, and we use pellet stoves instead of relying on the electric heater, improving the basement climate.
However, we plan to tear out the entire recreational room once we redo the drainage to eliminate the symptoms.
Thank you for your response! Yes, from what I understand, there is indeed a subfloor/wooden joists directly on the concrete, and that's the problem. In that case, just like you, we will be renovating the floors, but it is good to know that the problem can be temporarily solved with dehumidifiers.
Regarding the moisture in the attic, it is very common and nothing to worry about in most cases. Everyone who stays in the house emits moisture, and activities such as showering and cooking also release moisture. This rises with the heat and up into the attic through, for example, the attic hatch. Once up there, the moisture is released because cold air cannot hold as much moisture as warm air.
Good ventilation in the attic and sealing between the living area and the attic minimizes the risks. Keep in mind that good ventilation and a lot of ventilation are not always the same thing!
Good ventilation in the attic and sealing between the living area and the attic minimizes the risks. Keep in mind that good ventilation and a lot of ventilation are not always the same thing!