ᐅ Demolition and New Construction – How to Make Effective Use of a 761 m² Plot?

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:

• 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

I am wondering whether my post is in the right section here or if it should be moved to Floor Plan / Site Planning instead.

carstenhh schrieb:

• Building under Section 34 of the Building Code (without a detailed development plan/planning permission)?
• Partial sale of a plot in a semi-detached house construction?
• Affordable construction methods or shell houses (solid or prefabricated)?
• Designing a semi-detached house with as little contact to the neighbor as possible (e.g., staggered building sections, separate driveways, soundproofing, etc.)?

That’s a very broad question.

First of all, I would check whether you can even fit a semi-detached house with a site coverage ratio of 0.2. That will be tight – building footprint, garages, driveways, paved paths, and so on all count toward the site coverage ratio. It might be that if 0.25 is rejected, no reasonable planning is possible at all.

Otherwise: Section 34 depends on the surrounding development – the type and extent of building use as well as the construction method are the main points. Roof style does not count. So a lot is possible, but no special exceptions.

Partial sale is always an option (if a semi-detached house is feasible). Who takes which garden side? Who decides how the other half must look? That brings me to your last point. What if the buyer doesn’t want to build staggered as you do? What you see as an advantage might be a disadvantage for them. Or they don’t follow your wishes? Or you only want to sell half the plot as a planning package, and no one wants that?

Affordable can mean two different things. Off-the-shelf standard without special requests. Or self-building. By that, I mean DIY or personal contribution. Can you do that? Do you have the time? Do your friends have the interest and time? The construction method doesn’t really matter for the plot. A solid house can be a prefab house, and a prefab house can also be more expensive than a “solid” build. A house is a house (You probably mean timber frame construction as prefab – which has the advantage that energy efficiency can be easier to achieve. That’s about it.)

And finally: You want to build to have peace and quiet. But you may have to accept that you do get immediate neighbors again. Structurally, some things can be done. And it’s normal for garages and access paths to be on the right and left side of each half (buildings today are constructed separately anyway). Whether the plot allows that is another question and cannot be answered here. Having no contact with neighbors really points to a house in the countryside. In your small residential area (that’s what it is, right?), you will always have close contact with neighbors.

Thank you for your detailed response. It really helps me a lot.

Regarding the floor area ratio: According to the documents, it is actually 0.20 for my property, but since the neighbors have built more densely, I assume I can reach 0.25. That would be about 190 m² (2,045 sq ft) of buildable area, which would be enough for a small semi-detached house. If it stays at 0.20, it will be really tight – then probably only a smaller single-family house would fit.

About § 34 of the Building Code: I am following the surroundings. There are several semi-detached and single-family houses here, so nothing unusual is planned. Just simple, appropriate, and affordable.

For the partial sale, I plan to handle it as a concept sale. So: I will have the semi-detached house fully designed, with a clear layout and two separate driveways. Then I would sell one half including the design and building permit / planning permission. This way I keep control over the architecture and location, and the buyer has the advantage that everything is already prepared.

Regarding costs: I’m not aiming for a “cheap house,” but a simple, efficient house – rectangular, without a basement, with a pitched roof. I can do some of the work myself (painting, flooring, electrical, possibly drywall) with help from family (I have a few professionals in the industry in my family) and friends.

And yes, I’m more realistic about the privacy now. It’s not about not seeing anyone, but about having a clear separation. Separate driveways, private terraces. Hopefully this will be possible thanks to the corner plot location.

Best regards
Carsten

Then you should arrange an initial consultation with an architect to clarify the possible framework conditions. A preliminary building inquiry can also help to better determine the floor area ratio.

On a plot with a floor area ratio of 0.25, it is already possible to plan something attractive.

Would you like to share some information about your budget or the land costs?

In a single-story house design—with a converted pitched roof—a structural offset complicates the house profile on the municipal boundary side. It will likely be difficult to secure financing for this as a layperson, beginner, or first-time developer. However, this is not necessary to be a major partner in the project planning. The most cost-effective approach is usually to build a simple building shape with a supplier appropriate for the desired level of finishing. Shell-and-core homes are clearly more worthwhile for do-it-yourselfers than for turnkey individual contractors. Whether to choose a wooden or masonry structure should never be decided before the initial planning phase is settled.

First, design "Module A" for the entire semi-detached house, then offer the half to be sold with joint further planning—preferably only up to the shell stage—so that the co-builder can independently select the finishing trades. The boundary marking can then be determined depending on the municipal side once the planning is finalized.

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