Adding Floors vs. New Construction - How to Start?

Hello everyone,

I am new to the forum and hope that I am in the right place with my problem (otherwise please feel free to move it to the appropriate subforum - thank you very much).

I unfortunately have to provide some background.
My husband and I want to have our own home. We both grew up in houses with gardens, and it quickly became clear to us that we are not fans of apartments and long for a house.
After our wedding, we began to research new constructions. The plot of land was already decided, which I received as a gift from my parents (right next to their house). We quickly agreed that it should be a prefabricated house and arranged appointments with various providers.

In the meantime, unfortunately, quite suddenly and unexpectedly my mother passed away. Suddenly my father was left alone with a large house, and the original plan to build new next door became uncertain. Now, one should know that my father's house is from 1982 and in top condition (new roof, photovoltaic system, energy certificate = good values, etc.). It is a flat-roof house which, due to a change in building regulations, could now also be extended upward. My father has now offered that we could move into the house and have the entire ground floor (approx. 100 sqm) plus the attic (after the extension) — he would move into the existing granny flat.
According to a known structural engineer who reviewed the plans, an extension upward is apparently possible.

We have thought it through and could now well imagine this as an alternative to a new build. We know that quite a few legal matters still need to be sorted out beforehand (we don't want to invest blindly in a house that legally does not belong to us, etc.).

To finally decide between a new build (offers are now available) and an upward extension, we simply lack a feeling for the costs and the knowledge of how to obtain a quote.
Who is the right contact person for this? An architect, a carpentry company?
Whom should we contact first? Or do we have to write to each individual craftsman separately?

Additionally, we actually also need to submit a preliminary building inquiry to know whether our idea of the extension (knee wall > 1m) would even be approved. Does an architect, a structural engineer, or a construction company have to take care of this?

I think you see that we are a bit lost with the topic of the extension, and I would be very, very grateful for any advice.

Good day,

To finally decide between new construction (offers are now available) and an extension, we simply lack a feeling for the costs and knowledge of how to obtain an offer.
Who is the right contact person for this? An architect, a carpentry company?
Who should we contact first? Or do we have to contact each individual craftsman separately?

With the usual system providers, you are definitely in the wrong!

In addition, we would actually have to submit a building preliminary request to find out whether our idea of the extension (knee wall > 1m) would even be approved. Does an architect, a structural engineer, or a construction company have to handle this?

The first step should lead you to the structural engineer, who must finalize his initial assessment in writing. In the next step, consult an architect you trust and discuss the extension with him, and based on the structural requirements, prepare the design plan.

The further steps are - depending on the profession - debatable; if you ask two experts, you will get at least three answers. I would send the architect to the building authority and have him clarify the design planning; is there a prospect of approval this way? If you want absolute legal certainty, only the building authority approval (BVA) remains.

Regardless of how you have obtained a commitment regarding the building permit to be obtained, there are exactly two options for you to realize the construction after submitting the permit free of conditions. The first and best-known is to commission the architect with the individual awarding of contracts. This implies that you have to engage with every necessary step and sensibly contact three crafts enterprises each time. This is not the right decision for every builder because it can completely overwhelm a layperson. Many (husbands/partners) naturally see this differently, once hunter & gatherer, always an unwavering head with a tendency to overestimate. When this point occurs, it is advisable to trustingly leave the project to the architect as before in the selection and only retain a veto right regarding the fittings.

The other, rather lesser-known solution is to approach a local construction company that demonstrably specializes in renovations already during the approval phase with the plans. Here you can lean back - as with ordinary new construction - and only have to deal with his construction description before construction begins; the rest is taken care of by the builder for you.

In terms of cost, I always see the advantage of a fixed price, which only the builder will give you; pay attention to securities! An architect cannot provide this - nor does he want to, because then he would be liable like a builder/general contractor/general supplier/site manager. But that also means you will only receive full cost transparency when you receive the tender documents. Until then, the architect's cost estimate and the final price often differ by up to 20% or more. Completely legitimate, by the way.

Rhenish regards

Hello,

I just wanted to briefly report on the current status with us.
We first went to the building authority with the architect, and our plans were already dashed there. The development plan was very open to interpretation, but unfortunately not in our favor.

Therefore, we are now pursuing the construction of a prefabricated house.
Thank you very much for the helpful response!