Prefabricated wooden house provider for single-family homes in Lower Saxony

Thank you very much for your assessment!

But when using it, I don’t see the aforementioned price. In the sports room, you should be able to ventilate properly, possibly automatically right away. The often reduced ceiling heights in basements don’t always fit sports use (e.g., treadmill). Heating is also an issue. You can put a fan heater in, but it consumes a lot of electricity and the walls still radiate cold. I don’t find this very comfortable for sports or music.

We are planning 2.50 m clear height in the basement. At the moment, I do strength training in a 3x2 meter basement compartment without windows in a rental building. Therefore, my standards for the quality of stay in basement rooms are not exorbitantly high. Heating is not such a big issue for sports, of course it is for other activities. Maybe compensable by better insulation? Windows are planned. Automatic ventilation is not.

Where do the numbers come from? I now calculate quite a bit of the costs of a basement closer to and higher than the costs of living space. At €1250 it is a bare 2.10 meter high basement without plaster, wiring, and heating. So a basement-basement. Possibly even without stairs, which would need to be upgraded. Due to the lack of ventilation options and healthy climate, I definitely wouldn't do sports there, and because of the climate, I wouldn't store a musical instrument either – either it warps or it rusts/oxidizes. I also don't see crafting and sewing happening there. If that doesn't justify a living basement, then I don't know.

At the end of 2023, before we had contact with the architect, I had obtained a basement offer from one of the major prefabricated basement providers. Key data: 112 m2 with 17 linear meters of interior walls, 4 windows, 2.88 m height in shell construction, designed for the load case "constant pressing water," waterproof light wells, additional perimeter insulation of the basement exterior walls and below the slab. Costs were round about €115,000, so about €1,040/m2. With stairs + inflation I arrived at €1,250.

The standard of the finishing determines the price; there is no discount for the underground location. You can also hang a surface-mounted wired miner's lamp from the unplastered ceiling in above-ground rooms (careful wordplay).

I also find a fully finished basement more cozy. But if I optimistically spend 5 hours a week on the treadmill watching some YouTube, I can perhaps just about live with the surface-mounted wired miner's lamp. Expanding the living area upstairs is not really possible with a floor area ratio of 0.25. Besides, I find relocating the storage and technical room above ground not so attractive.

But you have already requested the three Holzers, with a preliminary design (probably because my house-building roadmap is still not required reading at German building schools). That was unwise, and at this stage, at least I no longer take on such mandates, or at least not without a significant penalty surcharge. Therefore, I now see two most obvious ways for you: A. You do the same again, only with a fourth Holzer and two Steiners. Then you can hopefully judge for yourself which of the Holzers you eliminate, and have two Steiner as "test candidates" to see if the offers remain similar when changing the construction method. Or B. You go to one of my Holzer-focused colleagues (Beuler aka prefab house expert or Freyermuth aka prefab house Guido, in Lower Saxony I would consider it nonsense to send you to colleague Zink in Bavaria) and have them evaluate the offers you have.

I read the roadmap on your blog for the first time in 2023. Our "dough resting" was maybe a bit too long at 6 months, but we were/are satisfied with the design result so far. I have not made any requests yet. Hence this thread. I have gathered most of my house-building knowledge from Mr. Beuler/prefab house expert and am/was currently following his recommendation: have architects create a preliminary design and then, based on that, get as comparable as possible offers from various construction companies and then have them evaluated. In this respect, maybe we are not yet at a stage where consulting services can only be bought with a penalty surcharge?

I am not familiar with drums and electric guitars, pianos and string instruments may require a regulated climate. And also in sports, one should start sweating from the "work," a controlled residential ventilation is, as mentioned, not any cheaper in the basement.

Organ, piano, and string instruments remain above ground. The basement is reserved for electric piano and percussion. The climatic requirements are less strict there.

If it's really flat, then why a basement?

Here I have to correct myself. The property actually has a slight slope of about 20cm over the building structure, which according to the "11ant basement rule" would lead to comparative savings of about €12,500. In return, the underground wasteland would at least be heated.

Key data: 112m2 with 17 linear meters of interior walls, 4 windows, 2.88m height in shell construction, execution for the load case "constant pressing water", pressure-tight light wells, additional perimeter insulation of the basement exterior walls and beneath the floor slab. Costs were around €115,000, so about €1,040/sqm. With stairs + inflation, I came to €1,250.

So without interior finishing?! With an interior dimension of 9x11, that is two cross walls that divide the basement into three bare rooms without electricity, flooring, lighting, and doors.

Key data: 112m2 with 17lfm interior walls, 4 windows, 2.88m height in shell construction, execution for the load case "permanent pressing water", pressure-waterproof light wells, additional perimeter insulation of the basement exterior walls and below the floor slab.

Is the basement then inside or outside the thermal envelope? If inside, then you have to heat or basic temper the basement. If outside, is the basement ceiling insulation to the ground floor and the insulation of the stairway including insulated door already included in the price?