ᐅ Humidity permanently too high, mold growth, possible causes?
Created on: 1 Nov 2024 20:40
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DrKingschultz
Hello everyone,
I have the following problem that has been bothering me:
We have a house of about 100sqm (1076 sq ft), all on one level, built in 2001 from clay blocks (probably similar to aerated concrete blocks?). The attic is unfinished; the ceiling consists of chipboard on top, then insulation, and paneling underneath.
The house meets the building and insulation standards from 2001, is plastered on the outside, and was repainted last year with silicate paint.
We have repeatedly had problems with clothing in the bedroom’s wardrobe developing mold or mildew.
Also, the wallpaper behind the bed (on an exterior wall) showed mold.
We hardly heated the bedroom, only occasionally during very severe frost, and never overnight. The bedroom is ventilated in the morning and evening with the window fully open.
Because of the mold issue, I recently bought three hygrometers and placed them in the bedroom, office, and living room.
In the living room (where the stove is located and in use from afternoon/evening), relative humidity (RH) is currently between 60 and 65%. This is at the upper limit but still acceptable, I think.
In the office (12sqm (129 sq ft)) the RH quickly rises to 70% when I am there. Only by heating a lot (normally I keep it at 19°C (66°F), now around 20°C (68°F)) and frequent short ventilation can I lower it to about 50%, but it rises again quickly. So I have to ventilate every 1–2 hours.
In the bedroom, the level is always 70% or higher. I heated it well for two days and ventilated crosswise several times a day, which lowered it to 60%, but it rises quickly again. In the mornings it can even be 80%.
Is all this normal? Am I doing something wrong? Could moisture be entering the building somewhere? I mean, I can’t heat all rooms constantly at 22°C (72°F) and ventilate all the time. I don’t want it that warm in the office or especially the bedroom. About 19–20°C (66–68°F) is enough for me in the office, and 16°C (61°F) is plenty in the bedroom.
In our previous apartment, the bedroom heater was never on, yet we never had mold.
What can I do to get the mold problem under control and permanently lower the relative humidity? Would renting a dehumidifier and drying out the building thoroughly be advisable? Or is that just addressing the symptoms?
I also checked for any damp spots on the ceiling or walls but found none.
I have the following problem that has been bothering me:
We have a house of about 100sqm (1076 sq ft), all on one level, built in 2001 from clay blocks (probably similar to aerated concrete blocks?). The attic is unfinished; the ceiling consists of chipboard on top, then insulation, and paneling underneath.
The house meets the building and insulation standards from 2001, is plastered on the outside, and was repainted last year with silicate paint.
We have repeatedly had problems with clothing in the bedroom’s wardrobe developing mold or mildew.
Also, the wallpaper behind the bed (on an exterior wall) showed mold.
We hardly heated the bedroom, only occasionally during very severe frost, and never overnight. The bedroom is ventilated in the morning and evening with the window fully open.
Because of the mold issue, I recently bought three hygrometers and placed them in the bedroom, office, and living room.
In the living room (where the stove is located and in use from afternoon/evening), relative humidity (RH) is currently between 60 and 65%. This is at the upper limit but still acceptable, I think.
In the office (12sqm (129 sq ft)) the RH quickly rises to 70% when I am there. Only by heating a lot (normally I keep it at 19°C (66°F), now around 20°C (68°F)) and frequent short ventilation can I lower it to about 50%, but it rises again quickly. So I have to ventilate every 1–2 hours.
In the bedroom, the level is always 70% or higher. I heated it well for two days and ventilated crosswise several times a day, which lowered it to 60%, but it rises quickly again. In the mornings it can even be 80%.
Is all this normal? Am I doing something wrong? Could moisture be entering the building somewhere? I mean, I can’t heat all rooms constantly at 22°C (72°F) and ventilate all the time. I don’t want it that warm in the office or especially the bedroom. About 19–20°C (66–68°F) is enough for me in the office, and 16°C (61°F) is plenty in the bedroom.
In our previous apartment, the bedroom heater was never on, yet we never had mold.
What can I do to get the mold problem under control and permanently lower the relative humidity? Would renting a dehumidifier and drying out the building thoroughly be advisable? Or is that just addressing the symptoms?
I also checked for any damp spots on the ceiling or walls but found none.
DrKingschultz schrieb:
Or does it simply accumulate there because it is in the corner of two exterior walls and at the very bottom, likely the lowest point and coldest, and with the nightstand also no air circulation?Exactly. The corner cools down the most because it loses heat on two sides.D
DrKingschultz12 Nov 2024 15:46The wall itself is fine, but there is moisture coming from the inside.
What is the best way to dry out the wall now? The corner is also the hardest to heat, even with the heating on. Would placing a fan heater in front of it and blowing warm air help?
In the future, it’s clear to place the bedside table differently so that there is 10cm (4 inches) of space all around. But first, I need to get the wall dry again.
What is the best way to dry out the wall now? The corner is also the hardest to heat, even with the heating on. Would placing a fan heater in front of it and blowing warm air help?
In the future, it’s clear to place the bedside table differently so that there is 10cm (4 inches) of space all around. But first, I need to get the wall dry again.