Two-family house new construction - Which costs to calculate?

  • Erstellt am 2015-11-23 16:02:36

Xorrhal

2015-11-24 10:58:51
  • #1
And what do experts estimate how long it takes to recoup these €22,000?

Does a back-of-the-envelope calculation apply that if €200,000 is KfW-subsidized (i.e. at 0.75%), I basically save €2,000 in interest annually, and correspondingly €20,000 over 10 years? Then it would almost be worth it, or am I seeing this wrong? If you then include the (hopefully) saved energy costs, one should make this investment, right?

How do you arrive at the costs for the foundation slab and roof, etc.?

My assumption was that the larger foundation slab and the larger roof cause roughly the same costs as a corresponding intermediate ceiling and the additionally required structural stability needed in the above-ground construction. Apparently, you see that quite differently?

I would be interested in the breakdown leading to €356,000 or €411,000, a bit more detailed, so I can better identify potential savings. At Kern-Haus (hope no one reprimands me for advertising) I saw a great house, planned turnkey at about €347,000, with 222m². It is only one living unit, but it is so large that with 1-2 additional walls you could almost build what we envision. Therefore, I am interested in your calculation.

Thanks a lot in advance!
 

Bauexperte

2015-11-24 11:25:34
  • #2
An intermediate ceiling does not have to be larger if the building has more floor area?

In a classic single-family house I have a max. floor area of maybe 12.00 x 12.00; rarely larger; on average it is probably around 8.00 x 10.00 m. So I have a floor slab of corresponding size, earthworks in the area of 10.00 x 12.00 m, depending on the slope angle, and a corresponding roof area. All the rooms preferred by the builders are accommodated in between; mostly on 2, sometimes even on 3 levels.

Now the builders want to accommodate all of that on 1 level. That means (in the example TEUR 411) that a floor slab of size 18.00 x 12.00 m is required, incl. working space 20.00 x 14.00 m of necessary earthworks must be carried out; the roof area also grows accordingly. Building on one level therefore requires significantly more investment than building upwards on a comparable normal floor slab.

These are my empirical values; estimated, as from realized construction projects.

Then ask the provider what it would cost you to just insert those "only" 1-2 walls; quite apart from the fact that a concrete bunker would not be my thing.

You are looking for flat rates, you will not be able to find those; nor can you compare every provider with every other provider. Kern Haus® builds according to the Lego principle, our construction is classic stone on stone. Kern Haus® pours concrete into Styrofoam, we stack monolithically without any external insulation, you have to add the costs of the soil survey, with us it is included in the fixed price, you have to pay for all earthworks additionally, with us the excavation and lateral storage (also with cellar) is standard, plastering the ceiling joints is subject to extra charges, with us it is part of the building contract, even the site setup – except for the construction fence – you have to pay for additionally... etc.; there are countless differences between their building contracts and ours. There are worlds between our building contracts; accordingly, different prices result.

So only compare apples with apples

Rhenish greetings
 

Xorrhal

2015-11-24 11:53:39
  • #3
An intermediate ceiling is no longer necessary if the house gets more floor space to fit everything - or am I mistaken?

But it is clear that the excavation, the slab, and the larger roof will be significantly more expensive than if all of that is "smaller" and I have to install an intermediate ceiling.

What are some "reference values" for the cost of the slab per square meter? And what does one square meter of roof cost? And what does building a wall cost per meter, roughly?

I somehow can’t imagine prices for that. For the interior work, I have "ballpark figures." 200 square meters of underfloor heating costs, say, €10,000. A normal bathroom with shower, sink, toilet, and tub about €10,000. A kitchen that suits us about €6,000... Those are investments we already had in the old house. But if I have a free piece of land in front of me, I can’t piece together costs for what will come at me until there’s something you can "walk into" with a roof over it and, say, windows inside - do you understand my problem?

My "dream" was an 80-100m² bungalow on the right, an 80-100m² bungalow on the left, between them a double garage, and roughly centrally above it all another 50-100m² upper floor for the bedrooms and children’s rooms of one bungalow. So that the garage basically forms the center of it all. Or to put it differently, maybe a semi-detached house where the garages are in the middle, and the upper floor is only for one house.

Do you understand what I mean, or do I have to get artistic?

But after your explanations, I will probably reach price ranges that are beyond good and evil, right?

But I also don’t want to run to an architect, have it planned, and then say “Ah no, unfortunately it costs €250,000 too much, I’ll come back next week” ^^
 

Bauexperte

2015-11-24 12:20:40
  • #4

Even with single-story construction, a ceiling above the ground floor is still needed, right?


Again - you cannot generalize house construction costs or break them down into percentages! Every provider has different fixed costs, which are reflected both in wages and trade prices. In Hamburg, the linear meter of walling costs less than in Bavaria; in Saarland, the square meter of roofing is more expensive than in Thuringia; every federal state has its own pricing structure.


The garage must therefore be built over on both right and left sides so that a) it forms a harmonious overall picture and you can access your bedrooms.


Depending on the chosen roof shape, estimated from EUR 500,000 plus, plus, plus.


You should give him your budget and see how close he can get to your desired appearance.

Rhenish regards
 

Xorrhal

2015-11-24 12:33:51
  • #5
Nobody plans something like that for me without a concrete goal, right?

I mean, I am right at the beginning of all questions. I am currently trying to clarify the financing to find out what would even be feasible given my financial circumstances. Once I know a capital volume, and know the land prices and various other costs, I can say what remains for the new construction.

I somehow want to put the third step before the first - or rather do it simultaneously.

At least I already know that it’s probably pointless to keep dreaming the "dream" from above, at least not until someone offers me €650,000 at unbeatable conditions



Back to this question again...?
 

MarcWen

2015-11-24 13:12:58
  • #6


Report on your experiences, gladly also via PM.

We are currently planning something similar, a single-family house with a granny flat for the parents-in-law. Since I am not a fan of a bungalow, that was never an option. Building everything on one level was also not a solution for us. Try to find a suitable plot for that. In addition, that quickly takes on the dimensions of a "hall."

The exact KfW conditions as of April 1, 2016, are not yet known. One can certainly be curious about the interest rate for 20 years. It seems certain that there will then be 100,000 euros per housing unit. As mentioned, the interest rates and possibly repayment subsidies are still open.

From my own experience, I can only advise you to consider an architect sooner or later. At the latest when you also think about an additional granny flat, i.e., plan 3 housing units.
 

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