Berlin Mitte has hundreds of interior designers. Some are excellent, some are not worth their fee, and most clients only find out which once the project is under way. A few specific questions beforehand will tell you whether a studio has the right expertise and whether you can work well together.
Ask these seven questions before you hire anyone. We answer them for our own studio too, as an interior designer in Berlin, so you can see what a clear answer looks like.
Question 1: Which work phases are included in the offer?
The German HOAI fee regulation defines nine work phases, from establishing the project basis (phase 1) to post-completion support (phase 9). Many interior designers only offer the design phases 1 to 5. Everything after that, meaning tendering, contract award and construction management, you then have to organise yourself or commission separately. With us it is part of interior design with construction management.
Ask specifically: which phases are included? Who manages the construction? Who coordinates the trades? Who is your contact while the work is carried out?
Question 2: How is the fee calculated?
Since the European Court ruling in 2021, the HOAI is no longer a binding price regulation. It now serves only as a guide. Interior designers today typically use one of three models: a fee calculated under the HOAI (10 to 20 percent of the construction sum), a fixed-price contract, or an hourly rate (80 to 180 € per hour, depending on experience).
A good answer is clear and ideally comes as a written fee estimate with a range. Be wary of "that depends on many factors" if no figures follow.
Question 3: Can you show me comparable reference projects?
Every interior designer has a portfolio. The more useful question is whether the studio has already completed a project similar to yours in size, style and constraints. A listed Altbau renovation calls for different experience than a modern new build.
Ask for two or three comparable references, with contacts among the clients. If a studio cannot or will not provide them, it should explain why.
Question 4: How do you handle permits and authorities?
Permits play a large part in Berlin Altbau projects: heritage protection, conservation areas, fire safety, structural engineering. Many interior designers work with external specialist engineers and architects on these. That is fine, as long as you know who does what.
Clarify: who submits the applications? Who deals with the district office? Who is liable if the permit is delayed or turns out differently than expected?
Question 5: How are decisions made during the project?
A building project is made up of a hundred small decisions. Who makes them when you cannot be reached? Do you get a call on Mallorca every time a socket moves? Or does the interior designer have room to decide some things alone?
Good interior designers put this in writing beforehand: what you decide together at the start, what the studio may decide on its own during the works within the agreed design, and which topics always come back to you.
Before you sign, get it in writing how decisions and extra costs will be handled.
Question 6: How are extra costs handled?
Nothing annoys clients more than extra costs nobody mentioned. Ask when additional costs can arise, above what amount you will be consulted and how variations are documented.
A reputable studio has a clear process for this: a written variation notice, your approval before the work is done, and documentation in the final invoice. If a studio stays vague on this point, treat it as a warning sign.
Question 7: What happens after handover?
There is still work after you move in: defects, warranties, small adjustments, reordering materials. Clarify: who is your contact in the year after handover? Is there an agreed follow-up inspection? How are warranty claims against the trades enforced?
How CARLO Design answers these seven questions
In the first conversation we give you a written overview covering all seven points. Our studio in Berlin Mitte works with clearly defined phases, one fixed contact per project and a transparent fee model. We coordinate structural engineering, fire safety and construction management ourselves, and we remain reachable after handover.
If you are thinking about hiring an interior designer in Berlin Mitte, we invite you to a no-obligation first consultation. Ask us these seven questions there. If the answers convince you, we can talk about your project.
What your own project will roughly cost, you can work out in two minutes. Work out your budget →