ᐅ Initial Questions About Prefabricated Houses, Garages, Underground Parking, and Energy Efficiency Programs

Hello house building community,

While searching for houses, I have also found some attractive plots and started looking into prefabricated homes. To roughly assess feasibility, I have a few questions.

A traditionally built solid house is not an option due to the high costs and the long wait for initial occupancy, which would result in double expenses that are simply too much. Whether it ends up being a prefabricated house or a shell house is still uncertain. Probably something where the plumbing is already installed but without flooring, wallpaper, etc.

Now to my questions.

I have some specific wishes. Option 1: Next to the (prefabricated) house, I would like a double garage that is taller than usual. I would like to have a small 4-post car lift inside to park a car that is rarely used and for repair work. Between the garage and the house, there should be a passage to the garden. My question: Is it possible to design a prefabricated house so that a balcony can be used on top of the garage on the upper floor?

Option 2 (preferred) would be an underground garage beneath the prefabricated house for at least 2 cars. Additionally, 1-2 cellar rooms would be an advantage. If a cellar costs about 30,000 (e.g. euros) roughly, how much more expensive would this option with an underground garage be, approximately? It would be ideal if a pit could be built in one parking space for car repairs.

I also have questions about KfW subsidies.

Is it true that with, for example, a KfW 55 house, you can get a loan of around 50,000 at about 1.5% interest PLUS a repayment grant of 5%? Meaning you would receive an additional 2,500? Many prefabricated homes do not provide information about KfW certification. Is this not offered?

What other costs are added to the house construction? Concrete slab foundations are apparently not included in the house price. A cellar is a MUST for us. I estimate earthworks to cost around 5,000. How high are the costs for preparing the construction site and installing electrical as well as water/sewer lines? What other costs should be expected? The assumption is a single-family house with approximately 10m (33 feet) by 10m (33 feet) floor area.

Best regards, Tobias

Hello Tobias,

You are making it a bit too easy for yourself. Please take some time to read through this forum, as the majority of your questions have already been discussed here many times. Thank you.

hg6806 schrieb:

A properly solidly built house is out of the question, as the costs would be too high and the initial occupancy would take many months, and the double burden would simply be too much.

With all due respect, this is nonsense. Even a prefabricated house is not built overnight after you sign the contract. Often—with some lead time—it takes significantly longer before the keys turn in the lock for the homeowner.

hg6806 schrieb:

Option 2 (favorite) would be an underground garage under the prefab house for at least 2 cars. Additionally, 1-2 cellar rooms would of course be advantageous. If you estimate roughly 30,000 euros for a basement, how much more expensive would this option with an underground garage roughly be? It would be perfect if you could also build a pit for car repairs in one parking space.

30,000 euros for a basement would probably only cover a partial basement.

For a floor area of 10 x 10 meters (33 x 33 feet), a usable basement would already cost around 40,000 to 45,000 euros. An underground garage would add around another 20,000 euros due to the required soundproofing, waterproofing against the living areas, and ventilation system. Another 3.00 meters (10 feet) deeper for a pit would likely add about 10,000 euros. All approximate prices assume good soil conditions; if the soil report has any surprises, costs can increase by 10,000 euros or more.

hg6806 schrieb:

What other costs are added to home construction? ... What else should be budgeted for? The assumption is a single-family house with roughly 10 x 10 meters (33 x 33 feet) footprint.

https://www.hausbau-forum.de/ratgeber/bauherrenhilfe.422/bauherrenhilfe-vor-vertragsabschluss.424/bausumme.662/#Baunebenkosten%20und%20Grunderwerbsteuer

Best regards, Bauexperte

hg6806 schrieb:

A fully solidly built house is not an option, as the costs would be too high and the initial move-in would take many months. The double financial burden would simply be too much.

This is a common misconception. Although the house itself can be assembled in just a few days, the construction of the house in the factory also takes considerable time.
A prefabricated house provider told us last October that their company's capacity was so fully booked that we could only expect the house assembly this October...

hg6806 schrieb:

Whether it will be a prefab house or a shell house is still uncertain. Perhaps something where the plumbing is already installed, but no flooring, wallpaper, etc., yet.

That somewhat contradicts your previous statements. With a shell house—most prefabricated house manufacturers offer various finishing levels—you would have to expect a lot of DIY work, and the double financial burden would still apply during this time. In my opinion, this only makes sense if you currently pay little or no rent and can renovate "at your own pace," meaning without financial pressure.

hg6806 schrieb:

Option 2 (favorite) would be an underground garage for at least 2 cars beneath the prefab house. Additionally, 1-2 basement rooms would be advantageous. If you estimate around €30,000 for a basement, how much more expensive would this underground garage option roughly be? It would be perfect if you could install a pit at one parking space for car repairs.

A basement involves significant costs for earthworks and possibly disposal fees! For a purely utilitarian basement measuring 10.64 * 9.84 meters (35 * 32 feet), we paid around €40,000 (a waterproof basement). Earthworks and disposal were not included in this price and could add another €10,000 to €15,000.
However, this basement was within the thermal envelope of our house and was therefore relatively straightforward to build.

Your idea of a garage underneath the house would require additional planning (garage within the thermal envelope, how to handle exhaust fumes, etc.), so this will likely be quite expensive.
It is certainly feasible with a prefab house manufacturer. You might need to hire an external basement specialist.

hg6806 schrieb:

Then I have some questions about KfW.

Is it true that for a KfW55 house, you can get a loan of €50,000 at about 1.5% interest plus a repayment grant of 5%? That means an additional €2,500?

Correct.

hg6806 schrieb:

Many prefab houses do not include information about KfW. Is this not offered?

Of course it is! Our house will be a KfW70 standard, but we could have chosen KfW55 as well.

hg6806 schrieb:

What additional costs are involved in house construction? Floor slabs are probably not included in the house price. A basement is a must for us. I estimate earthworks around €5,000. How much do site setup and laying of electrical and water/sewage connections cost? What other costs should I expect? Assuming a single-family home with roughly 10 x 10 meters (33 x 33 feet) footprint.

Best regards, Tobias

You can expect additional construction incidental costs of around €35,000 to €40,000 (excluding floor slabs or basement).

Best regards
Jaydee

hg6806 schrieb:

Next to the (prefabricated) house, a double garage that is taller than usual. I would like to have a small four-post car lift inside it ***
Option 2 (favorite) would be an underground garage under the prefabricated house for at least two cars

.. and as a follow-up to the above answers from me .... you first have to find a building plot where such a thing is allowed in the zoning plan (building permit / planning permission) ... maybe you will find one in a mixed-use or industrial area ..

hg6806 schrieb:
....
I also have some questions about KfW.

Is it true that for a KfW 55 house, for example, you can get a loan of 50,000 with about 1.5% interest PLUS a repayment grant of 5%? So you would get an additional 2,500?

Many prefabricated houses do not provide information about KfW. Is this not offered?


What other costs come with building a house? Foundation slabs are probably not included in the house price. A basement is a MUST for us. I estimate excavation work at about 5,000. How much do site setup and the installation of electrical and water/sewage lines cost? What other costs are there? Assume a single-family house with roughly 10m x 10m (33ft x 33ft) floor area.

Best regards, Tobias

The building expert already mentioned the additional construction costs. These definitely apply.

Regarding the basement, your estimate is too low.

For excavation work, any amount between 5,000 and 50,000 is possible, as it entirely depends on your plot and what needs to be done.

As for KfW, yes, there are definitely KfW 55 or better prefabricated houses. I have one. However, this usually means additional costs that you have to be able to afford. You receive a credit of 2,500 if proof is provided that everything complies. However, this amount is not paid out to you in cash but is applied to reduce your loan balance. Still, as mentioned, the additional costs are somewhat higher than 2,500 to move from KfW 70 to KfW 55.

We had to wait 11 months for our prefabricated house to be assembled, then another 3 months before we could move in.