ᐅ Demolition and New Construction – How to Make Effective Use of a 761 m² Plot?
Created on: 12 Nov 2025 11:05
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carstenhh
Hello everyone,
We have purchased a 761 m² (8,194 sq ft) plot with an existing building in Hamburg. Originally, the plan was to fully renovate the old house, but the condition is unfortunately so poor that we have now decided to demolish it and build new.
Since this is a corner lot and there is no formal zoning plan (building permit / planning permission) in place, the project will be evaluated under Section 34 of the Federal Building Code (Baugesetzbuch). There are already similar developments nearby, so we are allowed to build two units. The site coverage ratio is officially 0.20, but since neighboring plots are clearly built more densely, we realistically assume 0.25. One full story and one half story are permitted. We want to build without a basement.
Our initial dream was a single-family home that makes good use of the plot. We have two children and currently live in cramped conditions, so owning our own house would be a big step. However, building new will be financially challenging, so we are currently considering selling part of the plot and instead planning a semi-detached house (duplex) — so that we retain more land and can remain as independent as possible from the neighbor.
We want to build as cost-effectively as possible, but it doesn’t have to be a prefab house — I am open to ideas, suggestions, or alternative solutions on how to implement the project sensibly. Approximately 140 m² (1,507 sq ft) of living space would be perfectly sufficient for us.
Does anyone have experience or tips regarding:
I look forward to your assessments, experiences, or creative ideas on how to solve this project cleverly.
Best regards,
Carsten from Hamburg
We have purchased a 761 m² (8,194 sq ft) plot with an existing building in Hamburg. Originally, the plan was to fully renovate the old house, but the condition is unfortunately so poor that we have now decided to demolish it and build new.
Since this is a corner lot and there is no formal zoning plan (building permit / planning permission) in place, the project will be evaluated under Section 34 of the Federal Building Code (Baugesetzbuch). There are already similar developments nearby, so we are allowed to build two units. The site coverage ratio is officially 0.20, but since neighboring plots are clearly built more densely, we realistically assume 0.25. One full story and one half story are permitted. We want to build without a basement.
Our initial dream was a single-family home that makes good use of the plot. We have two children and currently live in cramped conditions, so owning our own house would be a big step. However, building new will be financially challenging, so we are currently considering selling part of the plot and instead planning a semi-detached house (duplex) — so that we retain more land and can remain as independent as possible from the neighbor.
We want to build as cost-effectively as possible, but it doesn’t have to be a prefab house — I am open to ideas, suggestions, or alternative solutions on how to implement the project sensibly. Approximately 140 m² (1,507 sq ft) of living space would be perfectly sufficient for us.
Does anyone have experience or tips regarding:
- Building under Section 34 of the Federal Building Code (without a zoning plan)?
- Partial sale of a plot when building a semi-detached house?
- Affordable construction methods or turnkey homes (solid / prefab)?
- Designing a semi-detached house with as little contact as possible to the neighbor (e.g., staggered building volumes, separate driveways, soundproofing, etc.)?
I look forward to your assessments, experiences, or creative ideas on how to solve this project cleverly.
Best regards,
Carsten from Hamburg
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nordanney12 Nov 2025 15:46carstenhh schrieb:
Well, the dream was actually a single-family house.Is another family living in your semi-detached house’s living room? That’s also a single-family house. Always keep that in mind ;-)carstenhh schrieb:
The question here would be how cheaply I could get a “simple” single-family house with about 130-140 sqm (1400-1500 sq ft) of living space. 🙁Town & Country, for example, offers this starting at a certain price. Turnkey. There are several other providers as well. If the standard features meet your needs, it gives you a first reference point (of course, additional costs will still apply that you as the builder have to cover).M
MachsSelbst12 Nov 2025 20:22300,000 EUR for the turnkey Flair 134, plus another 25,000 EUR worth of materials for DIY interior finishing (Town & Country typically only tiles the bathrooms/WCs, utility room, kitchen, and hallway are not included). About 50,000 EUR for additional construction costs, and then the demolition and disposal of the existing building, which should not be forgotten.
It will be at least 400,000 EUR, probably more.
And nothing has happened outside yet, not even the excavation and removal of soil for the foundation have been carried out and disposed of...
It will be at least 400,000 EUR, probably more.
And nothing has happened outside yet, not even the excavation and removal of soil for the foundation have been carried out and disposed of...
carstenhh schrieb:
Regarding the floor area ratio: According to the documents, it should actually be 0.20 for my property, but since the neighbors have all built more densely, I assume I can go up to 0.25. That would allow for about 190 m² (2045 sq ft) of buildable area, which would be enough for a small duplex. 190 m² (2045 sq ft) of floor area for a duplex, just for the house, means 95 m² (1023 sq ft) per unit, roughly 75 m² (807 sq ft) of living area on the ground floor—that’s a rough estimate, since the terrace is also included in the floor area ratio. For a single-story house, that would mean 125 m² (1345 sq ft) per dwelling unit. If you expect or need around 140 m² (1507 sq ft), it will be tight.
carstenhh schrieb:
I believe you. Well, the original dream was actually a single-family house. The question is how affordably I can get a “simple” single-family home with about 130–140 m² (1400–1507 sq ft) of living space. 🙁 That’s what @motorradsilke and Nordanney told you, among others. You should get some quotes.
carstenhh schrieb:
Separate driveways, private terraces. Hopefully, due to the corner location, that will be possible. The problem is that even if you build offset, for example an L-shape, you can’t put windows everywhere anymore because of fire protection regulations.
Another option would be an apartment you could sell, meaning a two-family house or a single-family house with a granny flat.
Is the land fully paid off?
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carstenhh13 Nov 2025 09:10ypg schrieb:
190 sqm (2045 sq ft) footprint as a duplex, just for the house, which means 95 sqm (1023 sq ft) per unit, about 75 sqm (807 sq ft) of living space on the ground floor—so roughly calculated, since the terrace is also included in the floor area ratio. For a single-story building, it comes to 125 sqm (1345 sq ft) per unit. If you count on needing 140 sqm (1507 sq ft), it will get tight.
This was mentioned to you, among others, by @motorradsilke and Nordanney. You should get a quote.
The problem is that even if you build staggered, for example in an L-shape, you can’t install windows everywhere due to fire protection regulations.
Another option is a unit that you could sell, like a two-family house or a single-family house with a secondary apartment.
Is the plot fully paid off? Unfortunately, the plot is not fully paid off. A secondary apartment sounds like an interesting option as well. Thanks for the suggestion.
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nordanney13 Nov 2025 10:06carstenhh schrieb:
Unfortunately, the plot is not fully paid off. A granny flat also sounds like an interesting option. Thanks for the suggestion.Do you think so? But you also have to build a larger area at a higher cost to have a tenant in your own house. It mostly has disadvantages. One advantage could be double subsidies.H
hanghaus202313 Nov 2025 11:16What does your bank say about the idea? Would they finance the project?
Example: I’m not assuming an expensive area.
Assuming purchase price of the plot 450,000 (including additional costs)
Demolition costs 50,000
Site development 10,000
Plot division 10,000
Planning costs 10,000
Sale of half the plot 300,000 since smaller plots are more expensive
Capital gains tax 45,000
Costs 575,000
Proceeds 300,000
Then the building-ready half of the plot cost you 275,000. You still need at least 400,000 for the new build.
Now you can insert your own numbers.
Example: I’m not assuming an expensive area.
Assuming purchase price of the plot 450,000 (including additional costs)
Demolition costs 50,000
Site development 10,000
Plot division 10,000
Planning costs 10,000
Sale of half the plot 300,000 since smaller plots are more expensive
Capital gains tax 45,000
Costs 575,000
Proceeds 300,000
Then the building-ready half of the plot cost you 275,000. You still need at least 400,000 for the new build.
Now you can insert your own numbers.
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