ᐅ Semi-detached house in Hamburg with a general contractor on own land, two plus full attic floors, no basement
Created on: 26 Jul 2025 12:27
1
1689owen
I’m looking for feedback on anything we might have overlooked. Tips on processes and organization are also helpful. (Details about the location, plot, and contractors involved will be shared later to keep things anonymous for now.)
We want to build a duplex and hire a general contractor (GC) for this. Each party has about €40,000 (approximately $44,000) available. The scope of self-performed work will differ slightly between the two parties but will mainly be limited to painting (including plastering and all related work) and flooring (excluding bathrooms). The attic may possibly be finished as self-performed work.
We have a few requirements:
According to the plans, we may build two full stories. We want to retain as much garden space as possible and, for this reason among others, would like to add a fully functional attic. By “fully functional,” we mean it can be used as living and working space and forms its own separate part of the apartment—not an open area connected to the stairwell (for example, the parents’ bedroom would be here). We were advised that having a concrete floor between the upper floor and attic would be sensible to achieve this. The attic could also be raised with a knee wall (dormer wall), which would greatly improve the interior height. Since the plans don’t specify maximum ridge, eaves, or gable heights, it will likely be restricted only by required setback distances. The setback to the neighboring plot is currently set at 3 meters (about 10 feet) for driveway, bike storage, and garage as border construction. This leaves a good garden area on the other side of the house.
kfw300 program:
This is very helpful for financing, almost essential for us. However, it comes with certain requirements that may cause additional costs. Which parameters would you recommend adjusting here?
Current status:
We have discussed financing preliminarily and set a budget framework. We already own the land. We are currently in talks with several GCs (ranging from smaller architecture firms, medium-sized companies, to larger firms like Baudirekt). We plan to decide on a GC in about a month. The options each GC offers will understandably influence our decision. We also still need to clarify whether we truly need and can afford a fully finished attic or if a pitched roof attic that could be finished later would suffice. A basement would probably be more expensive and provide less livable space than a full attic, so it is no longer a serious option. We plan to consult two or three more GCs to get feedback on possibilities and pricing.
Please feel free to ask any questions! This is already a lot of help. Maybe there’s even some additional advice out there. Thanks!
We want to build a duplex and hire a general contractor (GC) for this. Each party has about €40,000 (approximately $44,000) available. The scope of self-performed work will differ slightly between the two parties but will mainly be limited to painting (including plastering and all related work) and flooring (excluding bathrooms). The attic may possibly be finished as self-performed work.
We have a few requirements:
- Each party: 2 adults (bedroom, office) + 3 children (individual bedrooms)
- Total house footprint around 165m² (approximately 1,775 sq ft). A preliminary building inquiry has already been made.
- Noise protection necessary due to aircraft noise.
- Full attic living space
- kfw300 program
- Solid construction
- Brick facade
- Pitched roof
- Central ventilation system
- For both parties: rooms should not be too large (e.g., child’s room 10m² (110 sq ft), office 8m² (86 sq ft)); only one large open area for living and kitchen.
- Each half of the building should be easily separable in the future into an accessible unit (basement) and an apartment (upper floor + attic).
According to the plans, we may build two full stories. We want to retain as much garden space as possible and, for this reason among others, would like to add a fully functional attic. By “fully functional,” we mean it can be used as living and working space and forms its own separate part of the apartment—not an open area connected to the stairwell (for example, the parents’ bedroom would be here). We were advised that having a concrete floor between the upper floor and attic would be sensible to achieve this. The attic could also be raised with a knee wall (dormer wall), which would greatly improve the interior height. Since the plans don’t specify maximum ridge, eaves, or gable heights, it will likely be restricted only by required setback distances. The setback to the neighboring plot is currently set at 3 meters (about 10 feet) for driveway, bike storage, and garage as border construction. This leaves a good garden area on the other side of the house.
kfw300 program:
This is very helpful for financing, almost essential for us. However, it comes with certain requirements that may cause additional costs. Which parameters would you recommend adjusting here?
Current status:
We have discussed financing preliminarily and set a budget framework. We already own the land. We are currently in talks with several GCs (ranging from smaller architecture firms, medium-sized companies, to larger firms like Baudirekt). We plan to decide on a GC in about a month. The options each GC offers will understandably influence our decision. We also still need to clarify whether we truly need and can afford a fully finished attic or if a pitched roof attic that could be finished later would suffice. A basement would probably be more expensive and provide less livable space than a full attic, so it is no longer a serious option. We plan to consult two or three more GCs to get feedback on possibilities and pricing.
Please feel free to ask any questions! This is already a lot of help. Maybe there’s even some additional advice out there. Thanks!
1689owen schrieb:
And the thread is partly about the question of whether and how we need the attic / can afford it / can design it structurally. And about what tips you have on how we should think ahead.Until now, I wasn’t clear on what exactly you are aiming at here. Your question was very general: mistakes, what are you overlooking, organizational issues... 1689owen schrieb:
Total house footprint approximately 165m² (about 1776 sq ft). There was already a preliminary building inquiry for this.Let’s start over: assuming the same room requirements, but each being their own client, we agree that the footprint is about 165m² (1780 sq ft) divided by 2, so around 82m² (882 sq ft) footprint per unit. Now I wonder: what exactly does the preliminary building inquiry cover, who applied for and commissioned it? Was it done before the purchase? Has only one party bought the property and then is selling half to the other? Does the building inquiry refer to a single-family house or a semi-detached? Is there already a design? Will the plot be divided exactly in half? What is the orientation of the plot? Was the orientation considered in the building inquiry, or was it simply based on floor space index / floor area ratio?
Have parking spaces been requested? How many parking spots do you need? How many must you have?
Then the question: do you need to have the mentioned rooms fully finished at move-in? Are the children born yet? Could they initially share rooms because they are still young? Do you need a home office because remote work is a factor?
Are the additional construction costs (“Baunebenkosten”) as well as external works excluded from the 400,000€ (about 424,000 USD) budget? In other words: after spending 400,000€, will you still have enough left to cover ancillary costs and landscaping?
What exactly are the estimated +/- 400,000€? Is it a rough assumption or based on calculations from a bank or a financial service? Our forum also has a subforum where you can review your income and expenses to conservatively assess how far your budget can stretch. Then you can better estimate where to save, possibly with own work except for flooring or painting.
1689owen schrieb:
Based on what you wrote, @ypg, a room would definitely have to move to a higher floor.Let’s say this: with 65m² (700 sq ft) on the ground floor, I don’t see space for a home office, rather over 40m² (430 sq ft) of open-plan living area, a 4-5m² (43-54 sq ft) shower room, and the rest is taken by storage, stairs, hallway/wardrobe. For 5 family members, possibly a separate living room. So all roughly estimated. 1689owen schrieb:
Then the attic would be needed as living space.I wouldn’t rule that out. As said, the needs are not yet clearly defined—what is necessary or optional. nordanney schrieb:
Viebrockhaus & Co.: Furniture store
GU: Local joiner
For understandingThat could be confusing. The fact is that Viebrockhaus is a general contractor from northern Germany who delivers your customized house (here). However, I don’t see Viebrockhaus fitting into the budget at all. They charge very high premiums for everything. Whether that includes the house frame depends on how the plot is laid out.
1689owen schrieb:
(although the details and especially the decisions about which work will be done as self-performance will differ - but none of the parties will carry out entire construction phases themselves).
Your advice, @11ant, was even to independently (and possibly independently of each other) select companies after the shell construction. I think we would prefer some organizational simplicity here, if it is feasible price-wise. But maybe that conflicts with other goals? What other goals are you referring to? – I wasn’t thinking about self-performance at all, but “only” freedom in awarding the finishing trades. From experience, the left-half family is the electrician and the right-half family is the tiler, and the general contractor is too expensive for these special arrangements. It’s better for neighborly relations to have a better outlet than compromises. That’s why I see scenarios like yours working with a shared planner and shell contractor. A “shell plus” approach is always more advisable than “move-in ready minus.”
1689owen schrieb:
Where does the advice about timber come from? So far, we have been focused on masonry and solid construction. What have we overlooked? I’m not sure what has driven you towards “masonry only.” I have been involved in this field for four decades and usually consult both camps (see also > Turning Point). Certainly not to create unnecessary work for myself, but because I can still make an educated guess as to which construction method leads to the better overall solution in each individual case.
1689owen schrieb:
The duplexes with II+D, which I quickly found in a few more appearances, all have a studio variant upstairs, so a concrete ceiling plus knee wall would probably mean significant redesign and additional costs. Right? You can also find an explanation of the connections regarding concrete ceilings by me on “Build Now.” What you want to do above the eaves height with a knee wall again is completely unclear to me. Try drawing a basic cross-section sketch.
1689owen schrieb:
Once again on this (I think I now better understand where this advice comes from): So consulting an architectural firm and getting a design done? But that certainly costs money. If I then build with a different general contractor, that money might be (partly) lost. Or should I first look for several more general contractors, modify their catalog houses and have them prepare offers? And only then consider involving an architectural firm? What would be the recommendation here – and what does it depend on? [ / ] Possibly, a general contractor working according to their own procedures would prefer to do their own (re)design, which might then cost me money again, so I end up paying twice and stuck with the extra costs. Or where am I mistaken? I don’t know exactly what @Rübe1 had in mind with that advice, but in the end I would also recommend you go to an independent architect; see also my house-building roadmap. You never approach a general contractor without prior advice. Follow my roadmap and there won’t be any duplicated work.
1689owen schrieb:
Actually, I wanted to start by discussing general matters. Now there are numbers (and the estimate is only to show that we have thought about square meters per floor). [/] And in the thread, it’s also about the question of whether and how we need/pay for/structure the attic floor. The real experts start here with detailed questions about masonry and exterior wall thickness. You think about the number of floors with the architect in Module A when translating the room programs into the building volume. Possibly also two options, that is one half with and one half without a recessed top floor (I haven’t checked back whether such options would be possible).
1689owen schrieb:
I would guess that, for example, Viebrockhaus only builds their own houses. Or are they not a general contractor and I have confused terms here? ypg schrieb:
That might be very confusing now. The fact is that Viebrockhaus is a general contractor from northern Germany who delivers your tailor-made house here. However, I don’t see Viebrockhaus here at all cost-wise. They charge very high premiums for everything.
Whether that also applies to the building shell would depend on how the plot is shaped. Viebrockhaus is a general contractor, not only in northern Germany but not fully nationwide (not even throughout the NDR and WDR broadcast areas). People I advise build with them individually, but I prefer the model houses. I also see this provider as less suitable for you; in my opinion, they target private insured clients / FDP clientele. Extreme deviations from construction specification should choose other general contractors; otherwise, their premiums are fair and their offers transparent. As shell contractors, they would be my last choice since they clearly focus on move-in ready customers (who, however, often assign the garage or carport “by client”/self-performed).
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Papierturm29 Jul 2025 06:281689owen schrieb:
Once again on this topic (I think I now better understand where this advice comes from): So, visit an architect’s office and have a plan drawn up? But that probably costs money. If I then build with a different general contractor, that money might be (partly) lost. Or should I first look for a few more general contractors, modify their catalog homes, and request quotes? And only then think about bringing in an architect? What would be the advice here – and what does the advice depend on?
Thanks a lot in any case!Really interesting thread!Just a quick note from my own experience:
Last year, we became so frustrated trying to make general contractors comparable (and getting the contractors to comply with the zoning plan, which also proved very difficult) that we went to an architect who offered a fixed price for a general contractor planning.
This then led to the contractors actually becoming comparable.
Overall, the architect has so far not only cost us nothing but actually saved us money. (Part of their fee was deducted from the general contractor’s price, the architect eliminated an unfair claim from the contractor that we struggled to resolve ourselves, and they referred some service providers with significantly better value for money than what we found.)
As 11ant wrote: create a plan, present the plan to several general contractors, get quotes, and then review them.
In the end, we saved a lot despite the apparent extra cost of the architect.
I actually wanted to ask more questions and explain further, but time is tight right now. So, for now, just this:
Papierturm schrieb:How exactly did you proceed? Should I imagine it like this: you paid for the architectural planning and then simply submitted it to different general contractors, asking them to calculate the construction costs if you chose them? Did the general contractors not charge you for the cost calculations themselves? Did all the general contractors agree to do it this way?
That then led to the general contractors actually becoming comparable.
Papierturm29 Jul 2025 15:061689owen schrieb:
Actually, I wanted to ask more and explain further, but time is tight right now. So for now, just this:
How exactly did you proceed? Should I imagine it like this: you paid for the architect’s planning and then simply presented it to various general contractors (GCs), asking them to calculate the construction costs if you chose them? The GCs didn’t charge you for the cost estimation itself? Did all the GCs agree to this? Exactly. We paid for the architect’s planning and created a list of “must-haves” for the specifications (also important for comparability! This included things like shading, heating system, number of power outlets, and various other items).
This list was then presented by the architect to some selected GCs (both wood builders and masonry contractors). Most of them responded. We compared the offers together with the architect and then made a selection.
In the end, it’s like this: the providers want to sell. We’re talking about contracts, even for a small single-family home that quickly approaches half a million in revenue. (Of course, revenue is not the same as profit, but nonetheless, this is their livelihood.)
Only one GC did not respond and insisted on giving us an offer based solely on one of their standard floor plans. None of those complied with the zoning regulations. So we excluded that company.
Paying for cost calculations… that didn’t happen. And if a GC had tried that, honestly, they would have been excluded. How can you compare anything if no offer is made? (Especially since in our case, the issues of planning and specifications were already handled as mentioned above, meaning they even had less work than a customer who has to go through multiple revisions of a standard floor plan.)
Papierturm schrieb:
that we went to an architect with a fixed price for a general contractor (GC) planning. How should one imagine that?
Papierturm schrieb:
As 11ant wrote: create the design, present the design to several GCs, obtain bids, and then evaluate them. When did I write that? — As far as I remember, my advice is quite different: Planning module A with the independent architect, then a resting period with a decision point, followed by service phase 3 or the entire module B. Never approach the GC instead of a tender, but only involve them in the tender process. The bids resulting from the decision point neither qualify nor aim for Germany to cast the ultimate general contractor. They serve to calibrate budget-compliant planning. In the later search for construction companies after service phase 5, only specialists or craftsmen are involved.
Papierturm schrieb:
This ultimately saved us a lot, despite seemingly extra costs from the architect. The greatest savings come from the seemingly expensive service phase 5 of the architect; skipping it results in learning costs at least as high, and as a bonus, also creates problems with drywall work.
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