Hello everyone,
I am having problems with my garage; the entire ceiling is covered with black mold. I have to mention that it has a flat roof, and the garage is 9 years old. Since I have heard so many negative things about flat roofs, I suspected it might be leaking, so I called a professional to redo the roof. From what I saw, he just wanted to make money, as he charged 1200 euros just for labor (without materials) for 10 hours of work to cover 30 square meters (around 320 square feet). Well, that’s a story on its own. The fact is, I then researched online and read that the roof might actually not be leaking at all, and that the mold could be caused by other reasons. P.S. I have had this problem for many years. This year, I have been ventilating really well, so it is not due to poor ventilation. Last year, with poor ventilation, the floor was wet. So, this year I decided to leave the garage door open, and as a result, the floor is completely dry. But the ceiling still isn’t. This ceiling problem only occurs in winter! I am attaching pictures for you to look at and please help me. Can anyone tell me what is causing this? I don’t want to redo the roof if it isn’t leaking. Please, any tips or help on what this could be and what I can do would be much appreciated.
Please, I’m desperate; everyone just wants my money, whether it is necessary to do anything or not.
I am having problems with my garage; the entire ceiling is covered with black mold. I have to mention that it has a flat roof, and the garage is 9 years old. Since I have heard so many negative things about flat roofs, I suspected it might be leaking, so I called a professional to redo the roof. From what I saw, he just wanted to make money, as he charged 1200 euros just for labor (without materials) for 10 hours of work to cover 30 square meters (around 320 square feet). Well, that’s a story on its own. The fact is, I then researched online and read that the roof might actually not be leaking at all, and that the mold could be caused by other reasons. P.S. I have had this problem for many years. This year, I have been ventilating really well, so it is not due to poor ventilation. Last year, with poor ventilation, the floor was wet. So, this year I decided to leave the garage door open, and as a result, the floor is completely dry. But the ceiling still isn’t. This ceiling problem only occurs in winter! I am attaching pictures for you to look at and please help me. Can anyone tell me what is causing this? I don’t want to redo the roof if it isn’t leaking. Please, any tips or help on what this could be and what I can do would be much appreciated.
Please, I’m desperate; everyone just wants my money, whether it is necessary to do anything or not.
Hello spale,
There is a chance that the dew point is being undershot in the area of your garage ceiling—meaning water condenses there and mold can develop on this surface. Dew point undershooting happens when the surface of an enclosing room element is too cold for the (possibly warm) air inside the room.
For example: warm air meets a cold mirror, or someone wearing glasses comes in from the cold outside into a heated room and their glasses fog up. This issue can also occur in apartments if, for instance, the roller shutter boxes are not properly insulated—then you find no mold anywhere in the apartment except above the windows, where it can get as black as on your garage ceiling.
For an initial assessment, measure the average room temperature in your garage and the surface temperatures of the enclosing elements using an infrared thermometer (available at hardware stores for around €25). If the walls without mold have a higher surface temperature than your garage ceiling, this would be an indication. Then your garage likely does not have a “leakage problem” but rather a “building physics problem” that needs to be addressed.
Good luck!
There is a chance that the dew point is being undershot in the area of your garage ceiling—meaning water condenses there and mold can develop on this surface. Dew point undershooting happens when the surface of an enclosing room element is too cold for the (possibly warm) air inside the room.
For example: warm air meets a cold mirror, or someone wearing glasses comes in from the cold outside into a heated room and their glasses fog up. This issue can also occur in apartments if, for instance, the roller shutter boxes are not properly insulated—then you find no mold anywhere in the apartment except above the windows, where it can get as black as on your garage ceiling.
For an initial assessment, measure the average room temperature in your garage and the surface temperatures of the enclosing elements using an infrared thermometer (available at hardware stores for around €25). If the walls without mold have a higher surface temperature than your garage ceiling, this would be an indication. Then your garage likely does not have a “leakage problem” but rather a “building physics problem” that needs to be addressed.
Good luck!
Good evening,
first of all, I would like to sincerely thank you for this post. Believe me, I have been spending days researching on the internet.
I wanted to ask if it would help to create an opening on two opposite sides of the wall, about 300mm x 300mm (12 inches x 12 inches), and install a ventilation grille. The idea is to quickly remove the moist air. If the grilles are not enough given the airflow, I thought about installing a commercial 210mm x 210mm (8 inches x 8 inches) inline fan in one of the openings. Would that be effective?
Then I wouldn’t even need to insulate, just try with the two grilles and possibly the fan. Please advise.
first of all, I would like to sincerely thank you for this post. Believe me, I have been spending days researching on the internet.
I wanted to ask if it would help to create an opening on two opposite sides of the wall, about 300mm x 300mm (12 inches x 12 inches), and install a ventilation grille. The idea is to quickly remove the moist air. If the grilles are not enough given the airflow, I thought about installing a commercial 210mm x 210mm (8 inches x 8 inches) inline fan in one of the openings. Would that be effective?
Then I wouldn’t even need to insulate, just try with the two grilles and possibly the fan. Please advise.
During the day with light sunshine. The corner where there is no mold, that is, the side connected to the house wall, is not warmer than expected; it is the same temperature.
Could it actually be that the mold is caused by a thermal bridge since everything except that one corner without mold is moldy? Also, at the back by the door (exit) and the full width of the garage door?
Could it actually be that the mold is caused by a thermal bridge since everything except that one corner without mold is moldy? Also, at the back by the door (exit) and the full width of the garage door?
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