General Contractor or Design Studio in Berlin?

A general contractor suits a Berlin Altbau renovation when the work is precisely described before you sign, the building holds few surprises, and one contract with one contact matters more to you than comparing individual prices. A design studio with site management and separate contracts for each trade is the better fit when you will only know what needs doing once walls and floors are opened, when design and detailing matter, or when you want quotes and invoices checked on your behalf. The two can be combined: the studio plans and supervises, and the work goes to a few firms in larger packages.

In short · As of October 2026

The difference is who coordinates the trades and who checks on your behalf: with a general contractor it is the firm itself, with separate contracts it is the design studio’s site management.

	General contractor	Design studio, separate trades
Who designs	The firm, or a planner it hires	The studio, for you, down to the details
Who is liable for what	The firm for all trades	Each firm for its trade, the studio for design and supervision
Who checks invoices and progress	The firm itself, unless you hire someone	The studio’s site management
Price certainty	Lump sum for the work described	Lump sums and unit rates per trade, quantities as measured
Changes during the works	Through the firm, priced without competition	Priced one by one and checked by site management
Your effort	One contract	Several contracts, prepared by the studio
Typical fit	Clearly described work, little risk in the building	Altbau with open questions, a design with many details

Under the German Civil Code, defect claims for building work expire five years after formal acceptance in both models, or four years where the VOB/B applies and nothing else is agreed.

How a general contractor works on a Berlin renovation

A general contractor, in German Generalunternehmer or GU, takes on all the construction work under one contract. It carries out part of it with its own staff and subcontracts the rest, for example electrics, plumbing or parquet. It coordinates the trades, carries the risk where their work meets and is liable to you for the whole job. A Generalübernehmer, by contrast, builds nothing itself and passes all the work on.

For private clients, German law sets a framework. If a firm commits to substantial alterations to an existing building, the rules for consumer building contracts apply (section 650i BGB): the contract must be in text form, you have a right of withdrawal (section 650l), and the firm has to give you a building description (section 650j), unless you or your planner set the essential planning requirements.

A general contractor is a good choice when the scope is settled, such as a bathroom and kitchen in an apartment with renewed pipes and wiring. It gets harder in an Altbau when you only see what lies under the floorboards and plaster after demolition: uneven floors, old wiring, sometimes rotten beam ends. The contractor then adds a buffer to the price or raises extras, priced without competition.

How a design studio, site management and separate trades work together

With separate contracts, known in Germany as Einzelvergabe, you appoint an architecture or design studio that surveys the building, designs the work and writes a bill of quantities, the Leistungsverzeichnis. Every firm in a trade prices the same description with quantities, materials and standards, and you sign the contracts directly with the firms. The studio’s site management coordinates the trades, checks the work against the drawings and the invoices against the work done. In the German fee scale for architects and engineers (HOAI), this service is work stage 8, site supervision and documentation.

Because the studio describes the work, every firm prices the same project, and differences between quotes can be explained. In return, the risk where one trade hands over to the next is yours, from demolition, electrics and screed to joiners, painters and stucco plasterers. That is why this model only works with site management that is on site every week, sets the sequence and plans for Berlin specifics such as the house rules agreed with other residents.

What this means for cost and risk

A general contractor’s lump sum gives you certainty only as far as the work is described. Anything outside the description becomes an extra. As the client under a building contract you may order changes, and the firm may ask for adjusted pay for them (sections 650b and 650c BGB). Separate trades are often paid at unit rates: the price per unit is fixed and the quantity is measured on site. In an existing building that is often more honest, because quantities are only known once things are opened up, but someone has to check the measurements.

For defects, the firms that did the work are liable in both models. For work on a building, claims become time-barred five years after formal acceptance under section 634a BGB, and the same applies to claims against the planner for errors in design or site supervision. Many firms base their contracts on the VOB/B, and if nothing else is agreed, the period for building work is then four years. With a general contractor you have one contact for every defect. With separate trades it has to be established which trade caused a defect, which is what a documented acceptance for each trade is for.

One risk is often overlooked: a firm failing. With a general contractor the whole site stops, with separate contracts one trade has to be re-awarded. Whichever model you choose, if the project needs a building permit in Berlin, for example for structural work, the application is submitted by a planner entitled to do so, usually an architect or structural engineer. In social preservation areas (Milieuschutz) and for listed buildings, further approvals apply. Settle this before you hire firms, as described in Renovating a Berlin Altbau: permits and process.

Questions to ask before you sign

Which design is the price based on, will the bill of quantities be part of the contract, and what is explicitly excluded, such as levelling, protecting the stairwell, skips and hazardous waste?
What happens if something turns up behind the plaster or under the floorboards, and who decides on extras?
Are stage payments tied to verified progress, and is a retention held back until defects are fixed?
Does the VOB/B apply, and what limitation period for defects has been agreed?
Who checks the work and invoices on your behalf, and how often is that person on site?

What is most often missing from quotes is covered in Red flags in contractor quotes.

How CARLO Design works in Berlin

CARLO Design is a studio for architecture, interior design and construction management in Berlin. We are not a building firm. We design the work, submit the building application ourselves when one is needed, and run site management under HOAI work stage 8. Pre-qualified firms price the same bill of quantities, we check the quotes for completeness first and totals second, and you receive a comparison with our recommendation. We prepare the contracts, which you sign directly with the firms: clearly defined work as a lump sum, quantity-dependent items at unit rates.

During the construction phase, which starts at four to six months for a full renovation, we are on site every week. You receive a report with photos after each site meeting and the state of the budget every month, and we check every invoice against the work before you pay. We have worked with many joiners, stucco plasterers and parquet specialists for more than a decade. Our fee comes on top of the building costs: planning is 10 to 15 percent of the construction cost, and project management and site supervision are charged on top depending on scope and duration. More on our construction management in Berlin and building contractors in Berlin pages.

FAQ

Do I still need an architect if I hire a general contractor in Berlin?

Not necessarily for the construction itself. If your project needs a building permit, for example because it touches the structure, the application must be submitted by a planner entitled to do so, usually an architect or structural engineer. If you want someone to check the contractor’s work and invoices on your behalf, you can also appoint independent site management.

Is a general contractor’s lump-sum price really fixed?

It covers the work described in the contract. If you order changes, or extra work is needed to achieve the agreed result, the firm can ask for adjusted pay under sections 650b and 650c of the German Civil Code (BGB), depending on how the contract allocates the risk. The more precise the description, the firmer the price.

Who is liable for defects when trades are hired separately?

Each firm for its own trade. For work on a building, claims become time-barred five years after formal acceptance under section 634a BGB, or four years where the VOB/B applies and nothing else was agreed. The design studio is liable for errors in design and site supervision, also for five years. A documented acceptance for each trade makes the difference.

Is a general contractor more expensive than separate trade contracts?

There is no general answer. A general contractor builds coordination and risk into its price, while separate contracts add a fee for design and site management. In an Altbau, the deciding factors are often how many extras come up and whether someone checks the measured quantities.

What is a consumer building contract in Germany?

A contract under which a firm commits, towards a consumer, to build a new building or to carry out substantial alterations to an existing one (section 650i BGB). It must be in text form, you have a right of withdrawal, and the firm must provide a building description unless you or your planner set the essential planning requirements. Whether a contract for an Altbau renovation qualifies depends on the scope of the work.

Your next step

Tell us what you are planning for your apartment or house and whether you already have quotes. In the Project Check we look at the building and tell you which model we would choose in your position.

You can work out roughly what your renovation costs in two minutes. Open the cost and timeline calculator.

General contractor or design studio with site management for a Berlin Altbau renovation?