I am currently in the building permit / planning permission process and just found out through a call to the building authority that my property is located in the HQ100 EXTREME risk zone, so I have to take flood protection measures. This requirement has apparently been in effect since 2018 in Baden-Württemberg.
To explain: HQ100 EXTREME means there is a levee protecting my site next to the Danube River, but this levee could break (which seems very unlikely...). Because of this, I need to implement additional flood protection, whatever that may specifically involve. The exact wording states:
“At locations in risk areas outside designated flood zones, where no local land-use plan exists, construction projects may only be built or significantly extended using building methods adapted to the specific flood risk, according to generally accepted technical standards, provided this type of construction is technically feasible given the nature and function of the structure.”
I am building a solid structure without a basement, and my finished floor level is 61cm (24 inches) below this theoretical extreme flood level. I do not want to raise the ground level further. Although this would be technically possible, it would be expensive and would not look good.
I spoke by phone with the responsible official about whether I could build a wall around my property as a possible solution. She said she wasn’t sure if walls that high would be permitted there and reminded me to consider the entrance driveway. She recommended building 81cm (32 inches) higher for safety, but 61cm (24 inches) might be acceptable. However, I got the impression she wasn’t very knowledgeable. Maybe installing barriers or flood gates on the doors could work – I have seen sliding flood barriers online. Overall, this is really frustrating as none of the more than 100 houses nearby (all built before 2018) have anything like this, there has never been an extreme flood, and I think potential damage would probably be less than the cost of these measures. I also have insurance that costs an additional 100€ per year for flood coverage. To be safe, I will probably install my heat pump about 0.5m (20 inches) higher.
Does anyone have experience with this or a good idea on how to solve this as cost-effectively as possible?
To explain: HQ100 EXTREME means there is a levee protecting my site next to the Danube River, but this levee could break (which seems very unlikely...). Because of this, I need to implement additional flood protection, whatever that may specifically involve. The exact wording states:
“At locations in risk areas outside designated flood zones, where no local land-use plan exists, construction projects may only be built or significantly extended using building methods adapted to the specific flood risk, according to generally accepted technical standards, provided this type of construction is technically feasible given the nature and function of the structure.”
I am building a solid structure without a basement, and my finished floor level is 61cm (24 inches) below this theoretical extreme flood level. I do not want to raise the ground level further. Although this would be technically possible, it would be expensive and would not look good.
I spoke by phone with the responsible official about whether I could build a wall around my property as a possible solution. She said she wasn’t sure if walls that high would be permitted there and reminded me to consider the entrance driveway. She recommended building 81cm (32 inches) higher for safety, but 61cm (24 inches) might be acceptable. However, I got the impression she wasn’t very knowledgeable. Maybe installing barriers or flood gates on the doors could work – I have seen sliding flood barriers online. Overall, this is really frustrating as none of the more than 100 houses nearby (all built before 2018) have anything like this, there has never been an extreme flood, and I think potential damage would probably be less than the cost of these measures. I also have insurance that costs an additional 100€ per year for flood coverage. To be safe, I will probably install my heat pump about 0.5m (20 inches) higher.
Does anyone have experience with this or a good idea on how to solve this as cost-effectively as possible?
K
knalltüte19 Jun 2020 20:18Hi,
better play it safe.
The climate is changing (proven :cool), with more and more extreme weather events, including heavy rainfall. Since not all river and stream restoration measures have been completed yet, flooding still occurs, sometimes triggered by regions located significantly above the flood site.
In Münster, no one could have imagined a once-in-a-century rain event a few years ago. In MS, people paddled through the city on air mattresses (YouTube...). Many timber frame houses suffered total damage.
No matter what insurance covers, it’s never fun. Building 61cm (24 inches) higher certainly costs something, but it’s not “the end of the world” – right?
better play it safe.
The climate is changing (proven :cool), with more and more extreme weather events, including heavy rainfall. Since not all river and stream restoration measures have been completed yet, flooding still occurs, sometimes triggered by regions located significantly above the flood site.
In Münster, no one could have imagined a once-in-a-century rain event a few years ago. In MS, people paddled through the city on air mattresses (YouTube...). Many timber frame houses suffered total damage.
No matter what insurance covers, it’s never fun. Building 61cm (24 inches) higher certainly costs something, but it’s not “the end of the world” – right?
Just to clarify again: I already have insurance for this location, which costs 100€/year.
I am protected against a 100-year flood, but not against a dam breach caused by an HQ100 EXTREME event.
I simply don’t want to be almost one meter above the garden level, and if there ever were 60 cm (24 inches) of water in my house because I don’t have proper protection, that might not be a disaster for a solidly built house.
However, to prevent that from happening, I am looking for an affordable solution that does not involve raising the house.
I am protected against a 100-year flood, but not against a dam breach caused by an HQ100 EXTREME event.
I simply don’t want to be almost one meter above the garden level, and if there ever were 60 cm (24 inches) of water in my house because I don’t have proper protection, that might not be a disaster for a solidly built house.
However, to prevent that from happening, I am looking for an affordable solution that does not involve raising the house.
Affordable solutions are unlikely to be easy to find here; otherwise, millions would not be spent on flood protection. Water is not called a natural force for nothing. It simply finds its way through the smallest cracks.
If you are okay with your house being flooded, then implement cheap temporary measures just to be able to build. If you want peace of mind, raise the ground level.
I have seen flood damage before (fortunately I was never personally affected). And if, after months, your house is still damp and your furniture is floating away... trust me, that is not something you want.
If you are okay with your house being flooded, then implement cheap temporary measures just to be able to build. If you want peace of mind, raise the ground level.
I have seen flood damage before (fortunately I was never personally affected). And if, after months, your house is still damp and your furniture is floating away... trust me, that is not something you want.
Considering the recent years and how flood situations have worsened, I believe €10,000 is a good investment.
If it were the same here, I would rather spend the €10,000 than take the risk of being the one, with a chance of 1 in 10,000, to lose my entire house in the worst case.
In a few years, I would probably think, "Well, I could have saved that money."
But I would much prefer that over thinking, "If only I had spent the money back then."
If it were the same here, I would rather spend the €10,000 than take the risk of being the one, with a chance of 1 in 10,000, to lose my entire house in the worst case.
In a few years, I would probably think, "Well, I could have saved that money."
But I would much prefer that over thinking, "If only I had spent the money back then."
Ötzi Ötztaler19 Jun 2020 21:24
Regarding the cheap pseudo measures, only the authorities can tell you what they accept and what they don’t in order to grant the building permit / planning permission. Maybe they will consider flood-resistant installed building services sufficient.
Truly effective measures, on the other hand, are very expensive and not exactly attractive visually. But please keep us updated on what you ultimately implement. Good luck with the building permit / planning permission.
Truly effective measures, on the other hand, are very expensive and not exactly attractive visually. But please keep us updated on what you ultimately implement. Good luck with the building permit / planning permission.
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