Hey community,
Can someone please tell me how to waterproof basement walls (foundation) to prevent groundwater from penetrating?
Attempts have already been made to make the basement walls thicker, but moisture still comes through the walls and now also through the floor (older building) – the rubble stone walls are about 0.5 to 1.8 meters (1.6 to 5.9 feet) high and wet.
It all started when the neighbor, who recently moved in, raised his garden by about 1 meter (3.3 feet) on average.
Thanks in advance for your answers – I’m worried that a three-story house might collapse…
Can someone please tell me how to waterproof basement walls (foundation) to prevent groundwater from penetrating?
Attempts have already been made to make the basement walls thicker, but moisture still comes through the walls and now also through the floor (older building) – the rubble stone walls are about 0.5 to 1.8 meters (1.6 to 5.9 feet) high and wet.
It all started when the neighbor, who recently moved in, raised his garden by about 1 meter (3.3 feet) on average.
Thanks in advance for your answers – I’m worried that a three-story house might collapse…
B
Bauexperte13 Sep 2015 12:48Hello,
I am quite certain that you will not make further progress without professional advice. Professional advice means that an expert inspects the situation on site and then explains which type of waterproofing or sealing you need to apply.
It is almost certain that you will have to expose the exterior basement walls (detached or semi-detached house?). Depending on the soil conditions and the existing building materials, the expert can then tell you which measures must be taken and in which order. The relevant standards (DIN) specify various types of sealing methods.
Sealing the slab floor will probably be somewhat more complicated, but at least—since it must be done from above—it will reduce the clear ceiling height. I can think of a variety of options here; however, as with new construction and everywhere else, it depends. Every construction project must be considered individually, and it would be unhelpful for me to recommend a single measure knowing that other solutions might better prevent the incoming water in the long term!
Someone MUST come out and examine the situation on site. Only then can you be sure to take the correct and permanently effective measures. Regardless of whether you can carry them out yourself or need a specialist company.
Regards, Bauexperte
Miki29 schrieb:
Attempts have already been made to make the basement walls thicker => moisture is still coming through the walls and now also through the floor (old building) – the rubble stone walls, about 0.5 - 1.8 meters (1.5 - 6 feet) high, are wet.
It all started when the neighbor who recently moved in raised his garden by about an average of 1 meter (3 feet).
I am quite certain that you will not make further progress without professional advice. Professional advice means that an expert inspects the situation on site and then explains which type of waterproofing or sealing you need to apply.
It is almost certain that you will have to expose the exterior basement walls (detached or semi-detached house?). Depending on the soil conditions and the existing building materials, the expert can then tell you which measures must be taken and in which order. The relevant standards (DIN) specify various types of sealing methods.
Sealing the slab floor will probably be somewhat more complicated, but at least—since it must be done from above—it will reduce the clear ceiling height. I can think of a variety of options here; however, as with new construction and everywhere else, it depends. Every construction project must be considered individually, and it would be unhelpful for me to recommend a single measure knowing that other solutions might better prevent the incoming water in the long term!
Someone MUST come out and examine the situation on site. Only then can you be sure to take the correct and permanently effective measures. Regardless of whether you can carry them out yourself or need a specialist company.
Regards, Bauexperte
Hello Miki,
without guarantee or claim to completeness or accuracy:
I have the same issue in my older house with rubble stone walls, where we clearly have damp but not wet walls. If water is dripping or running into your basement, the following suggestion probably won’t be useful:
We achieved good results without excavating outside by drilling holes inside the relevant walls at about 25-30cm (10-12 inches) above the floor, angling them downward at about 30° with a large drill bit. The holes are spaced between each other.
A product called “Verkieseler” (a silicate-based solution) is then filled into these holes. It is less viscous than water and crystallizes upon contact with moisture, sealing the gaps between the stones. You monitor how much Verkieseler is absorbed (slowly seeping into the wall) and keep adding more until the solution remains in the hole and the wall no longer absorbs it. This can require a large quantity and many holes. This procedure should be done or supervised by someone with prior experience.
The result is not perfect but significantly better than before (this was four years ago). In the long term, we will likely still have to excavate at least one wall (in our case, the driveway), which is basically the same problem as your neighbor’s garden.
The cost including labor (DIY drilling, anyone can drill the holes) and Verkieseler was about 2,000–3,000 Euros. Excavating everything from the outside would certainly have cost us at least ten times more.
At some spots, it will likely need to be repeated now, but some walls have been completely dry since then.
Additional note on sealing the foundation slab: in our house, built in 1918, the rubble stone walls were constructed first, and then the foundation slab (if any) was poured from the inside. This means the walls do not rest on the foundation slab, but directly on soil, gravel, or similar. This might also be the case in your situation, and if that is the weak spot (which I don’t think based on your description), it requires a different solution.
Best regards
Dirk Grafe
without guarantee or claim to completeness or accuracy:
I have the same issue in my older house with rubble stone walls, where we clearly have damp but not wet walls. If water is dripping or running into your basement, the following suggestion probably won’t be useful:
We achieved good results without excavating outside by drilling holes inside the relevant walls at about 25-30cm (10-12 inches) above the floor, angling them downward at about 30° with a large drill bit. The holes are spaced between each other.
A product called “Verkieseler” (a silicate-based solution) is then filled into these holes. It is less viscous than water and crystallizes upon contact with moisture, sealing the gaps between the stones. You monitor how much Verkieseler is absorbed (slowly seeping into the wall) and keep adding more until the solution remains in the hole and the wall no longer absorbs it. This can require a large quantity and many holes. This procedure should be done or supervised by someone with prior experience.
The result is not perfect but significantly better than before (this was four years ago). In the long term, we will likely still have to excavate at least one wall (in our case, the driveway), which is basically the same problem as your neighbor’s garden.
The cost including labor (DIY drilling, anyone can drill the holes) and Verkieseler was about 2,000–3,000 Euros. Excavating everything from the outside would certainly have cost us at least ten times more.
At some spots, it will likely need to be repeated now, but some walls have been completely dry since then.
Additional note on sealing the foundation slab: in our house, built in 1918, the rubble stone walls were constructed first, and then the foundation slab (if any) was poured from the inside. This means the walls do not rest on the foundation slab, but directly on soil, gravel, or similar. This might also be the case in your situation, and if that is the weak spot (which I don’t think based on your description), it requires a different solution.
Best regards
Dirk Grafe
Thank you very much for both responses.
I thought I might get away with some kind of trick to avoid the excavation around it.
Well, then I guess it’s time to roll up my sleeves and get to work.
Could someone perhaps tell me how high the risk of collapse is with damp basement walls? There is no dripping, but the sand between the stones is moist enough to rub off.
I thought I might get away with some kind of trick to avoid the excavation around it.
Well, then I guess it’s time to roll up my sleeves and get to work.
Could someone perhaps tell me how high the risk of collapse is with damp basement walls? There is no dripping, but the sand between the stones is moist enough to rub off.
T
toxicmolotof14 Sep 2015 13:51This is not my area of expertise, but you should avoid unplanned excavation work without professional (and liability-related) planning.
DANGER TO LIFE!
And before this is dismissed as an overreaction... every year houses collapse in Germany and elsewhere, where basements have been improperly exposed, regardless of whether the walls are damp or dry!
DANGER TO LIFE!
And before this is dismissed as an overreaction... every year houses collapse in Germany and elsewhere, where basements have been improperly exposed, regardless of whether the walls are damp or dry!
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