Costs for our construction project

Hello everyone,

this is my first post and I am a layperson in the field of house construction, but I am very curious and eager to learn. Therefore, I ask for your understanding if I do not fully understand something yet or if I am completely off the mark.

My wife and I are expecting a child and are therefore planning our own home more concretely. We have already read and researched a lot, also here in the forum, but the topic of house construction is vast, especially if you have had nothing to do with it before.

We would like to build a modern, simple house, preferably with a flat roof or a gable roof without overhangs, for a family of four. We already have the plot (approx. 20mx40m, flat) and there are no additional purchase costs for it. Ideally, the house should meet the Efficiency House 55 standard and have a modern heating system, e.g. geothermal energy with a trench collector. Since the building envelope probably has to be completely airtight, we can hardly avoid a controlled residential ventilation system. However, we have not yet settled on a specific construction method. We will have an architect advise us on what is best or most affordable in our specific case. A basement is not planned. For pure living space (excluding traffic areas) we have thought of the following:

Ground floor: Open living/dining area 40-50m² / Study/guest room 10sqm / Guest WC/bathroom 5m²
Upper floor: Bedroom 20m² / Master bathroom 10m² / Children’s rooms 2 x 15m² / Children’s bathroom 5m²

We would prefer to have the technical room and some storage space in an (integrated into the building structure) garage, provided this does not exceed the financial framework. We want to leave out the exterior facilities for now.

The complete electrical installation would be handled by the parents-in-law with their electrical company. In addition, we have a carpentry business in the family and many friendly craftsmen in the village.

We want to build near Rastatt in BW and commission an architect with the overall performance. What do you think what costs we will face? Are there still important details missing for an approximate estimate? Do you think we could manage with a budget of €250,000? Or what are the critical points?

I would be glad to receive many replies.

This is my first post and I am a layperson in the field of house construction, but I am very curious and like to learn. Therefore, I ask for your understanding if I do not yet fully understand something or am completely off the mark.

No master has ever fallen from the sky – but curiosity and willingness to learn are already good prerequisites (always these clichés ).

My wife and I are expecting a child and are therefore planning our own home more concretely. We have already read and researched a lot, also here in the forum, but the topic of house construction is vast, especially if you have had nothing to do with it before.

Then I hope you have already made a rough calculation and thereby come to the target of 250,000 euros.

We would like to build a modern, simple house, preferably with a flat roof or a gable roof without overhangs, for a family of four. We already have the plot (approx. 20mx40m, flat) and there are no additional purchase costs for it. Ideally, the house should meet the Efficiency House 55 standard and have a modern heating system, e.g., geothermal with trench collector. Since the building envelope probably has to be completely airtight for this, a controlled residential ventilation system is almost unavoidable. A basement is not planned. For pure living space (without traffic areas), we have thought of the following:

Ground floor: Open living/dining area 40-50m² / Study/guest room 10m² / Guest WC/bathroom 5m²
Upper floor: Bedroom 20m² / Parents’ bathroom 10m² / Children’s rooms 2 x 15m² / Children’s bathroom 5m²

We would preferably have the technical room and some storage space in a garage integrated into the building structure, provided that does not exceed the financial framework. We want to leave outdoor facilities out for now.

Living space with 2 hallways then amounts to about 150 sqm. Not considered here is a potential utility room (washing machine, dryer, etc.) – I don’t know to what extent you want to integrate that into the technical room (garage).

150 sqm x flat rate 1,500 euros = 225,000 euros + garage 15,000 (as I learned earlier from construction expert )
However, in my opinion, this is not a KfW 55 house – max KfW 70. How much the technology will cost you, I cannot say. Geothermal counts as one of the more expensive systems in initial investment. Insulation depends on the building material (e.g., with Ytong no additional insulation is needed) – ventilation still makes sense (layman’s opinion).

How much the "integrated garage" would cost or save, I cannot tell you either.

Taken together, it will get pretty tight – there are no incidental building costs yet (35k, safety buffer 10k, etc.).

The complete electrical installation would be taken care of by the parents-in-law with their electrical company. Furthermore, we have a carpentry in the family and many friendly craftsmen in town.

No idea how high the savings potential would be.

I think you are on a good path, might have to increase the budget a bit and then definitely need your own work.

That’s the opinion of another layperson who has also only been reading here for a few months.

We built the following: Prefabricated house KFW55 with gas heating, controlled residential ventilation, and solar collectors. Living-dining area + kitchen approx. 50 sqm, bedroom 22 sqm, children's rooms each 18 sqm, bathroom 10 sqm, guest bathroom just under 5 sqm, utility room 8 sqm, office 10 sqm. Wood-burning stove. All together approx. 150 sqm (including a small bay window), no basement. We did the floors and wallpapers mostly ourselves. House price including all additional costs approx. €280,000 (pure house price €225,000 + €10,000 material and labor for own work (tiler for 40 sqm)).

However, we left a lot in the standard version. We could easily have sunk another €20,000 by making changes to doors, bathroom furniture, and stairs. Still, I would describe our home as stylish and modern. Technically, it is definitely impressive. We hardly have to heat, and the climate in the house is always relatively good.

Since you are expecting offspring, and I myself drove from the delivery room to the construction site, I advise you: take another year. Construction site and baby don’t go together if you don’t build completely turnkey. In addition, having a child makes you more realistic about the financial effort. We also underestimated it, but currently, so that my wife can work again a bit, we pay about €700 for childcare. There is a subsidy from the youth welfare office, but we don’t know it yet. And the tax refund will only come in the middle of next year.

OK. We already almost suspected that it might be tight :/ Crazy that you can’t build a simple single-family house anymore for a quarter of a million. The house construction is planned for next year. By then, our little one will already be a few months old. It will work out. But well, we should probably expect €270,000-€300,000.

We also thought at first, with €250,000 you should be able to buy/build something.... Pustefix In the end, a 4 was at the front

Hello,

The house should ideally meet the Effizienzhaus 55 standard and have a modern heating system, e.g. geothermal energy with a trench collector.

Measured against the energy costs actually saved later on, I consider KfW 55—at least in solid construction—to be worth considering a few times. The required investment is not insignificant, even though trench collectors are usually the cheapest alternative. Is the plot large enough for the ring trench collector? You must maintain a minimum distance of 1.00 m, sometimes even 2.00 m, from the property boundary all around.

Ground floor: Open living/dining area 40-50m² / Study/guest room 10m² / Guest WC/bathroom 5m²
Upper floor: Bedroom 20m² / Master bathroom 10m² / 2 x Children's rooms 15m² / Children's bathroom 5m²

We would prefer the technical room and some storage space in an (integrated into the building) garage, provided this does not exceed the financial budget. We want to leave the outdoor facilities out of consideration for now.

Then you need about 190 sqm of floor area, which roughly corresponds to 158 sqm of pure living space. If the technical equipment is to go into the garage, this part practically has to be developed as living space; a "caretaker" helps little here, even if some colleagues see it differently. Also, you have to consider that this variant involves longer pipe runs => additional costs.

Single-family house with internal roof, KfW 70: TEUR 245
Garage 3 x 9, incl. insulated technical room: TEUR 21
Additional cost KfW 55: TEUR 21 (geothermal heat pump with trench collector)
Additional building costs: TEUR 30
Painting work in extra list: TEUR 10
Floor coverings in extra list: TEUR 10
Outdoor facilities in extra list: TEUR 10
Reserve for extras: TEUR 10

All in estimated: TEUR 357

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Single-family house with flat roof, KfW 70: TEUR 270
Garage 3 x 9, incl. insulated technical room: TEUR 21
Additional cost KfW 55: TEUR 21 (geothermal heat pump with trench collector)
Additional building costs: TEUR 30
Painting work in extra list: TEUR 10
Floor coverings in extra list: TEUR 10
Outdoor facilities in extra list: TEUR 10
Reserve for extras: TEUR 10

All in estimated: TEUR 382

Both estimates refer to the Rhineland; in BW you can expect additional costs of 3-5%.

The complete electrical installation would be done by the parents-in-law with their electrical contracting company. In addition, we also have a carpentry company in the family and many friendly craftsmen in the village.

You should always carefully consider whether the family can handle the burden resulting from any warranty issues.

Rhenish greetings