Hello!
I hope this is the right subforum.
Here is the situation: Our neighbors are currently excavating about 0.50 - 0.6 m (20 - 24 inches) away from our garage to a depth of approximately 1.50 - 1.80 m (59 - 71 inches). Our garage is built on strip foundations. I don’t know the exact depth of these, but I assume they extend to a maximum of 80 cm (31 inches). No underpinning, shoring, or battering/sloping was done during the excavation. About 0.5 m (20 inches) from our garage, the ground is now excavated straight down to at least 1.50 m (59 inches) depth.
According to my understanding of standards like DIN 4123, if no additional underpinning measures are taken, excavation up to 2 m (6.5 ft) next to the garage should only go to a maximum of 50 cm (20 inches) above the foundation base, which is about 30 cm (12 inches) deep. Only beyond 2 m (6.5 ft) distance can excavation be carried out deeper with a proper slope or batter. Otherwise, appropriate section-by-section underpinning should be carried out professionally.
Are my concerns about the structural stability of the garage foundations justified, or am I mistaken? We have already spoken with the neighbors, but they rely on their contractor. If my concerns are valid, what would be reasonable next steps I can take to ensure the stability of the garage? The location is the federal state of Hesse.
I would really appreciate any advice anyone can offer here.
I hope this is the right subforum.
Here is the situation: Our neighbors are currently excavating about 0.50 - 0.6 m (20 - 24 inches) away from our garage to a depth of approximately 1.50 - 1.80 m (59 - 71 inches). Our garage is built on strip foundations. I don’t know the exact depth of these, but I assume they extend to a maximum of 80 cm (31 inches). No underpinning, shoring, or battering/sloping was done during the excavation. About 0.5 m (20 inches) from our garage, the ground is now excavated straight down to at least 1.50 m (59 inches) depth.
According to my understanding of standards like DIN 4123, if no additional underpinning measures are taken, excavation up to 2 m (6.5 ft) next to the garage should only go to a maximum of 50 cm (20 inches) above the foundation base, which is about 30 cm (12 inches) deep. Only beyond 2 m (6.5 ft) distance can excavation be carried out deeper with a proper slope or batter. Otherwise, appropriate section-by-section underpinning should be carried out professionally.
Are my concerns about the structural stability of the garage foundations justified, or am I mistaken? We have already spoken with the neighbors, but they rely on their contractor. If my concerns are valid, what would be reasonable next steps I can take to ensure the stability of the garage? The location is the federal state of Hesse.
I would really appreciate any advice anyone can offer here.
H
hanghaus202317 Sep 2025 11:51Just by the way. Although it turned out okay in the end, why doesn’t anyone intervene immediately when the neighbor plans to build a pool? For me, it’s no longer acceptable as soon as the excavator starts work.
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MachsSelbst17 Sep 2025 19:21hanghaus2023 schrieb:
Just as an aside. In this case, it fortunately turned out well in the end. But why doesn’t anyone intervene immediately when a neighbor is planning to build a pool? For me, once the excavator starts digging, that’s where I draw the line. Because when dealing with a professional company, you generally assume they will take the necessary measures to shore up, support, and secure everything properly.
I can’t always stand at the garden fence with the building authority when an excavator enters my neighbor’s property, just because I assume the operator might cause major problems right away.
MachsSelbst schrieb:
Because with a professional company, you would generally expect them to take the necessary measures to support, shore up, etc. You can’t always stand next to the building inspector at the garden fence every time an excavator enters your neighbor’s property, assuming the operator will cause major damage right away. Yes, that is what you would expect. Unfortunately, I have been on far too many construction sites where that was not the case. Then experienced workers tell me, “We have been doing it this way for the last 25 years…” and it’s always the same mistakes. Usually, there is an effort to cut corners to complete the job faster, easier, or more profitably.
Having a building inspector present all the time is not necessary, but if something seems odd, it’s important to question it critically and essentially proceed as the original poster (OP) did here.
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MachsSelbst17 Sep 2025 19:54Well, the criticism here was that one should have proactively acted almost clairvoyantly before the work even began to prevent this situation from arising.
This is very difficult for a layperson because, as a rule, they can only judge based on a gut feeling whether something is right or not... and nobody wants to call building control / the building inspector immediately, risk alarming the neighbor, only for the inspector to say in the end, "What do you want? It looks fine."
And as you can see, it took a forum like this to come up with the idea of involving building control or, if necessary, the police.
People just don’t want to ruin their relationship with the neighbor, with whom they will have to get along for 20, 30, or 40 more years, by causing a scene right away. Ultimately, you can’t blame the neighbor either. There are plenty of people who have no clue about structural engineering, technical details, etc., and genuinely believe that it will hold up if the construction company says so.
This is very difficult for a layperson because, as a rule, they can only judge based on a gut feeling whether something is right or not... and nobody wants to call building control / the building inspector immediately, risk alarming the neighbor, only for the inspector to say in the end, "What do you want? It looks fine."
And as you can see, it took a forum like this to come up with the idea of involving building control or, if necessary, the police.
People just don’t want to ruin their relationship with the neighbor, with whom they will have to get along for 20, 30, or 40 more years, by causing a scene right away. Ultimately, you can’t blame the neighbor either. There are plenty of people who have no clue about structural engineering, technical details, etc., and genuinely believe that it will hold up if the construction company says so.
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