ᐅ Single-family house / townhouse, 150 sqm, possibility for 2 plots – Feasibility check

Hello,

I am new to the forum and have been reading through many of the topics over the past few days. It’s a real treasure trove of knowledge and experience—great resource!

We are still in the early stages of our homebuilding project. To avoid obvious mistakes early on, my idea is to start asking questions and introduce the topic here from the beginning. Better to stumble early than fail late.

## Here is what has happened so far:

- We currently live in a 101 sqm (net internal living area) or 108 sqm (including terrace) apartment, with a small basement (about 12 sqm (130 sq ft)), an underground parking space, an outdoor parking spot, a shared bike storage room (where our 3 bikes are stored), and a small garden (about 28 sqm (300 sq ft)), very efficiently laid out with 5 rooms. From this, we derived a realistic requirement for our future home, as we find this size just right for us.
- We visited a prefab home exhibition near Fellbach (close to Stuttgart) and looked at several houses and spoke with consultants from different manufacturers (Okal, Weberhaus, Bittermann, and Weiss).
- We visited the new development area Steinriegel in Wendlingen and examined 3 available plots for sale. All three plots would be suitable for us with various pros and cons.
- We had a first meeting today with another prefab home manufacturer who has built a house in the area. We hope they can assess the local conditions better than other manufacturers since they built a house just 5 plots away—though based on forum research, I fear we might be expecting too much.
- We have an initial meeting with our house bank in a few days to get a first indication of our budget.
- We are educating ourselves on the subject.
- We started this thread.

## Plots

The two prioritized plots:

A: Detached house, flat roof 0–5°, 345 sqm (about 3,713 sq ft), €850/sqm, €294,000, 3% agent fee, max building height 6.5 m (21 ft 4 in), plot ratio 0.4 → buildable area 138 sqm (1,485 sq ft), relatively flat, number of full floors = 1. The text includes this note: “According to § 19 (4) 2 in conjunction with § 19 (4) 3 of the Federal Land Utilization Ordinance, the plot ratio set in the graphical part of the development plan can be exceeded up to a value of 0.6 by areas of installations per § 19 (4) 1 Nos. 1, 2, and 3 of the Ordinance.”

B: Townhouse, pitched roof 30–45°, 268 sqm (about 2,884 sq ft), €850/sqm, €228,000, 3% agent fee, max building height townhouse 4.5 m (15 ft), max building height detached 9.0 m (29 ft 6 in), plot ratio 0.45 → buildable area 120 sqm (1,292 sq ft), “steep” with an estimated 12.3% slope (extracted from elevation profiles in the site plan), number of full floors = 1. The text here contains the same sentence as above with 0.7 as the value.

Using our basic knowledge, we estimate that on both plots the requirement for size (110 sqm + basement + garage, or 150 sqm without basement + garage) should be achievable within the building boundaries (one full floor plus a 66% floor above).

## Budget

Our budget situation is still somewhat unclear to us, and we are working on clarifying it (primary step: the bank meeting this week). Our situation:

- The current apartment is not fully paid off, and we have 3 loans arranged through the house bank for it (a “never do this!” financing setup with 2 standard annuity loans and 1 home savings contract, paid into for 10 years and then used for repayment). From today’s perspective, all have very favorable conditions but are not paid off. Since everything is through the house bank, it is the sensible first point of contact for a rough realistic framework.
- Primarily, our equity (so the idea goes) will come from either
a) selling the apartment *after moving into the new house in about 2-3 years* and taking over the loans for the new house while using the remaining sales proceeds as equity, or
b) selling the apartment *after moving in* and paying penalties to exit the loans early, with the remaining sales proceeds forming the equity.

As an initial estimate, we have said that we see €750,000 total costs as feasible. €800,000 to €850,000 only if everything goes positively with the bank. Costs beyond that are unimaginable. As mentioned, we want to cross-check this also from the bank’s perspective.

## Process flow

As far as I understand, the sequence for realization should be:

1) Plan the specific house as much as possible without owning land yet
2) Check financing with the bank using rough numbers
3) Buy the specific plot, financed via the bank
4) Develop the house plans in more detail since we can now do soil testing etc.
5) Check financing again with the bank
6) Order the house through the prefab home manufacturer (general contractor - is that correct?), financed via the bank
7) Have the house finished
8) Sell the apartment and thereby “secure” the equity

## Additional costs

Weberhaus gave the following figures as a rough first indication for plot A, the detached house with a relatively flat plot:

- €3,000/sqm (for 150 sqm: €450,000 or 110 sqm: €330,000)
Additionally:

- Garage €40,000
- Surveyor €2,500
- Sewer connection €5,000
- Electricity connection €3,000
- Water connection €2,500
- Media connections €2,500
- Road closure €2,500
- Construction water/electricity €1,500
- Associated architect €16,000
- Building permit application €500
- Soil report €2,500
- 7% notary/tax on land (€21,000 or €16,000)
- Civil engineering/earthworks €50,000
- Outdoor facilities €30,000

Sum of additional costs for plot A:
- €181,000

The variant with 150 sqm without basement on plot A would therefore be:
€450,000 (house) + €181,000 (additional costs) + €294,000 (plot)
= €925,000 total.

## Requirements

- We currently think we need either
a) Net living area (meaning excluding heating system, washer, dryer, terrace, garage, walls) of 110 sqm WITH basement, or
b) Net living area 150 sqm WITHOUT basement
- Additionally, garage for 1 car and 3 bicycles (next to the house)
- 5 rooms

## Timeline

We were shocked not only by the prices but also by the estimated durations:

- Agent: 6–9 months for building permit here in the city
- Weberhaus: 18 months from building permit
- Okal: 12 months from building permit
- Bittermann: 2 years from building permit

## Next steps

Our goal for the end of the week is:

- a reliable estimate of the budget
- a reliable estimate of prefab home costs on both plots
- a reliable estimate of our requirements
- decision: cancel or continue the project

I struggle with these questions because we have no reliable gut feeling yet and therefore depend on numbers. Getting these numbers is harder than expected :-)

##

Questions for you:

- When is the right time to hire an independent architect (or “planner” as often called here in the forum—what exactly does that mean?) to design a house with us? What are typical costs as a rough indication in the Stuttgart area? How do I find a “good” one?
- What else can and should we do to get a realistic cost estimate before going to the bank?
- Is the sequence outlined above correct? Where are the major thinking errors?
- What else can and should we do in the current situation? What is the logical next step? (Goal: continue or cancel project)
- Which of the above-listed amounts in additional costs are realistic, which are too high or too low? What might be missing?
- For these lump-sum estimated amounts, do we always need to add a “10% contingency for unforeseen costs” on top?
- Which cost items change significantly if we take plot B with a 12% slope? Are there initial estimates or rules of thumb? For example, “earthworks factor 2” or similar?
- Where do you immediately see the biggest deal-breaking concerns and risks? At which steps? My personal gut feeling is: 1) that the entire financing is based on speculation that the apartment will be sold in about 2.5 years with proceeds coming in, otherwise we have a financing gap; 2) that you buy a plot and later the construction project fails because the specifically planned house—contrary to the roughly planned one—turns out to be much more expensive (financing gap).

##

If total costs reach €925,000, we will not pursue the project further. That exceeds what we would be willing to pay for something “small,” even before talking about interest rates and uncertain proceeds after selling the apartment. That would be madness in our view. When madness turns into “yes, let’s do it,” we don’t know yet. We are in the initial discovery phase, as you can tell from my limited knowledge. Our minimum “space pain threshold” is described above based on our current living situation. We do not want to downgrade. Because the house will have stairs vs. an apartment, we set 110 sqm as the minimum net internal living space for us if a basement and garage are included.

Thank you in advance for any comments—please feel free to critique thoroughly and give clear opinions if there are major errors. That is exactly why I am here.

Schokoriegel schrieb:

With total costs of €925,000, we will not pursue the project any further.

Then this thread ends very quickly.

As a general rule, today you can calculate approximately €3,000 per sqm (about $280 per sq ft) of living space for construction costs of a move-in ready house (there is no upper limit depending on your preferences). In addition, you always have ancillary building costs—regardless of who you build the house with.
Then you have a basic shell house and still need (or rather want?) the large double garage. External works such as driveway and terrace will definitely add to the costs as well.
And of course, the land.

nordanney schrieb:

Then you have a bare house and still need (need or rather want?) the large double garage. Landscaping or driveway and terrace will definitely be added later.
And of course the plot of land.

If all of this really needs to be done immediately and only this area is suitable, I would keep saving and stay in the apartment.
Otherwise, I suggest drastically cutting back:
Cars can stand outside for now, a small wooden shed is enough for bicycles, possibly reduce the size of the house without a basement (find suitable floor plans).

In such expensive areas, construction costs are usually very high as well.

I find Weberhaus’s pricing quite reasonable. Most others list significantly lower prices, so additional costs should be expected.

However, it’s also clear that you don’t necessarily need an expensive double garage: usually, a carport with a storage room for bikes and a lawnmower is sufficient.

If a net living space of 110 square meters is enough for you, then 130 square meters can also work with a well-designed floor plan.

Considering the two plots and their “size,” you should expect extra costs for a sloped site in order to create even a small flat area for a garden.

But let’s be realistic: how old are you? Can you afford to wait longer, over your lifetime, for another plot C, D, or E to become available?

There are also alternatives to a detached single-family home, such as a townhouse, semi-detached, or terraced house. Or a pre-owned property.

There are alternatives to the “expensive” prefabricated house manufacturers, although it must be said that Weber has realistically calculated an average of 3000 €/sqm (approximately $280/sq ft). However, there are regional construction companies where you might save on some trades. What I want to say is: just because there is a big home improvement store nearby for inspiration, doesn’t mean the local builders’ boutiques offer inferior houses.