Andy70
2017-10-03 00:18:34
- #1
Hello,
I have a single-family house (built in 2001, which I bought from the then owner in 2006) and for years I have had damp basement walls, getting worse and worse, now with mold on the walls. Apparently, only the walls facing the garden on the outside are too damp. This was shown by the measurement of a building biologist. The other basement walls are enclosed by the garage, terrace, and front stairs, etc. But some of these walls are also slightly damp, especially near the floor, but not extremely.
Today I dug up a small area at the outside wall down to the base slab and saw that the bitumen coating is only present in the upper area (about 30-35 cm). Below that, down to the base slab, everything is unprotected (!). You can practically see the bare bricks that were just plastered. No wonder the walls have been damp for 16 years (room humidity often 83%). At least there is a cove fillet present. We will dig up everything this weekend (with an excavator) and a friend wants to waterproof it later with a bitumen thick coat (4-5 mm) and dimpled membranes.
I have 3 questions regarding this:
1) How long should the walls be allowed to air out from the outside after the soil around has been removed before applying bitumen? Of course, it will be protected against rain in the meantime with a tarp. Is 3-4 weeks enough? From the inside, a dehumidifier (capacity: 20 liters/24 hours) has been running since today.
2) Does the existing cove fillet now need to be removed and newly made, or can the existing one be used and simply coated with bitumen? I am not really an expert and am unsure whether the cove fillet may have suffered and become porous after 16 years of wet soil underneath. Or is a bitumen coating sufficient there if it is solid and apparently looks "good"? In the one place where we dug, it looks good from a distance. We will only know more exactly during the weekend when the entire area is excavated. But what matters to me at first is generally whether that is mandatory because it was unprotected for so many years or whether it is not necessarily required. A friendly bricklayer (via two degrees of separation) told me that this is not really a problem. Clean it, apply bitumen, and that’s that. Is that correct?
3) The building biologist and a remediation company told me that the two walls that are not built against anything on the outside are the culprits. The other walls have presumably soaked up water over the years that has entered there. That’s why they are also slightly damp. I could dry the rooms gradually with a dehumidifier. The dehumidifier has already been running since today. Can it be true that the moisture from the two affected walls has spread over all those years through half of the basement? The humidity in all other basement rooms is also very high (above 75% and sometimes even over 80%).
Thanks already for your tips.
Many greetings Andy
I have a single-family house (built in 2001, which I bought from the then owner in 2006) and for years I have had damp basement walls, getting worse and worse, now with mold on the walls. Apparently, only the walls facing the garden on the outside are too damp. This was shown by the measurement of a building biologist. The other basement walls are enclosed by the garage, terrace, and front stairs, etc. But some of these walls are also slightly damp, especially near the floor, but not extremely.
Today I dug up a small area at the outside wall down to the base slab and saw that the bitumen coating is only present in the upper area (about 30-35 cm). Below that, down to the base slab, everything is unprotected (!). You can practically see the bare bricks that were just plastered. No wonder the walls have been damp for 16 years (room humidity often 83%). At least there is a cove fillet present. We will dig up everything this weekend (with an excavator) and a friend wants to waterproof it later with a bitumen thick coat (4-5 mm) and dimpled membranes.
I have 3 questions regarding this:
1) How long should the walls be allowed to air out from the outside after the soil around has been removed before applying bitumen? Of course, it will be protected against rain in the meantime with a tarp. Is 3-4 weeks enough? From the inside, a dehumidifier (capacity: 20 liters/24 hours) has been running since today.
2) Does the existing cove fillet now need to be removed and newly made, or can the existing one be used and simply coated with bitumen? I am not really an expert and am unsure whether the cove fillet may have suffered and become porous after 16 years of wet soil underneath. Or is a bitumen coating sufficient there if it is solid and apparently looks "good"? In the one place where we dug, it looks good from a distance. We will only know more exactly during the weekend when the entire area is excavated. But what matters to me at first is generally whether that is mandatory because it was unprotected for so many years or whether it is not necessarily required. A friendly bricklayer (via two degrees of separation) told me that this is not really a problem. Clean it, apply bitumen, and that’s that. Is that correct?
3) The building biologist and a remediation company told me that the two walls that are not built against anything on the outside are the culprits. The other walls have presumably soaked up water over the years that has entered there. That’s why they are also slightly damp. I could dry the rooms gradually with a dehumidifier. The dehumidifier has already been running since today. Can it be true that the moisture from the two affected walls has spread over all those years through half of the basement? The humidity in all other basement rooms is also very high (above 75% and sometimes even over 80%).
Thanks already for your tips.
Many greetings Andy