ᐅ New Construction Planning – Where Do I Start?

Hello everyone,

after posting the question “extension or new build” in another thread yesterday, and already leaning toward a new build, I’m now trying to make a “plan” for what I actually need to do...

My problem is knowing what step to take first.

Of course, I first need to find out whether I can even finance the project.

For that, the bank advisor wants to see a cost estimate for the project so they can tell me if it’s financially feasible.

To create a reasonably accurate cost estimate, I need a building plan and quotes.

But I can only get those once the architect knows the plot and the other conditions.

However, I don’t have the plot yet, so I don’t know its costs or the conditions.

It’s a bit of a catch-22.

Intuitively, I would say I estimate the costs as accurately as possible. That only works with a lot of reading, calculating, and thinking. But how do I tell good advice from bad?

I can fairly well narrow down what the plot will cost. Real estate portals like Immowelt and others offer plenty of information to estimate these costs. With €120,000 including all fees (property transfer tax, notary, soil analysis), I should be safe here in our region (Saarland)—if anything, a bit on the low side.

The additional construction costs were already well outlined in a related thread here—I should be fine with €50,000, judging from a quick read of that thread (I plan to study it more thoroughly once I get started).

But how do I arrive at a price for the house? Prefabricated house suppliers offer attractive prices, but something is always off with the example plans. And every change adds cost. On top of that, there are many negative reports about these prefab houses. This actually makes me want to work with a local architect I know, who I would potentially entrust with the whole project and its supervision. On the other hand, I worry whether such a “small” architect is really the best choice for me, or whether, due to other projects, they might not devote as much attention to my project as I expect...

I’ve gotten a bit off-topic—but these questions are really pressing for me.

Back to the main point: Rules of thumb like X€ per square meter or Y€ per cubic meter only provide a rough guideline. When I include features like a granny flat, garage, and so on, I can’t seem to come up with a number I, as a complete layperson, can really “understand.”

If I calculate, say, 250m² (2700 sq ft) of living space at €2000 per m² (€185 per sq ft), I’m already at €500,000 excluding the plot, additional construction costs, or anything else. That sounds excessive for a detached house with a granny flat...

If I calculate based on a footprint of 10 × 14m (33 × 46 ft), two full floors (each 3m (10 ft) high), and a standard pitched roof (1.5m (5 ft) average height), I get 10 × 14 × (2 × 3 + 1.5) = 1050m³ (37,100 ft³) of enclosed volume, which, at €400 per m³ (€11 per ft³), comes to €420,000. That still sounds like a lot for a detached house with a granny flat, right?

Considering that a bathroom, at €25,000, is probably the “most expensive” room (I have an offer for the extension we once planned), I can’t imagine the house costing 20 times that amount!

I’m looking for someone, preferably several people, who can guide me step by step and show me how to approach this.

The more blogs, forums, and pages I read, the more confused I get. That’s why I’m creating this own thread here, hoping it will lead me to the goal—or at least show me the way...

Best regards,
Xorrhal & Family