Contract sum

For most clients, the contract sum is simply "the price." For the seasoned real estate professional, however, it is merely a starting point. The contract sum is the amount for which the contractor commits to realizing the work, including VAT. But anyone who thinks this amount marks the finish line is in for a rude awakening. In practice, the contract sum often functions as a financial floor, not a ceiling.

The Mechanism Behind the Contract Sum

At its core, the contract sum is a trade-off of risks. You purchase certainty for a price. However, that certainty is never absolute. A contract without loopholes does not exist, and it is precisely in those loopholes—the "not included" items—that the builder's profit margin and your financial risk reside.

The total investment of a construction project (the realization costs) consists of three layers, of which the contract sum is only one:

1. The Contract Sum: The "hard" construction costs as stipulated in the contract.
2. The Variables: Provisional sums, settlable quantities, and additional work (variations).
3. The Indirect Costs: Professional fees (architect, structural engineer), permits, and utility connection fees.

“A low contract sum is often a harbinger of high additional work costs. The art is not to negotiate the lowest price, but the most complete one.”

The Three Financial "Levers"

There are three mechanisms that will set your final invoice in motion, even with a "fixed" price:

1. Provisional Sums: The Estimate as a Weapon

A provisional sum is an amount reserved for components that are not yet definitively specified (e.g., "€15,000 for the kitchen"). Here lies the trap: contractors can make a quote optically cheaper by estimating provisional sums low. When you later choose a kitchen costing €25,000, you pay the difference—plus often a profit percentage on that difference—out of your own pocket.

2. Additional Work (Variations): The Margin Maker

Additional work arises with every change after the contract signing. From an extra socket to a different type of facing brick. Because competition is absent at that moment (you are locked in with your contractor), prices for additional work are often 20% to 50% higher than market rates. Strategic advice: specify everything before the signature is set.

3. The "Ukraine Clause" (Cost-Increasing Circumstances)

Since the recent volatile market, many contractors use clauses that pass on price increases of materials (steel, wood, insulation) to the client. This means that your fixed price is not fixed if the global market isn't.

Strategy: From Quote to Manageable Contract

Never accept the contract sum "as is." Use the following tactics to strengthen your position:

• Demand an 'Open Calculation': Request insight into the cost breakdown. This forces the contractor to be transparent about their margins and risk surcharges.
• Fix the Provisional Sums: Convert provisional sums into fixed prices by making choices (sanitary ware, tiles) early on. Or agree on a "maximum settlement price."
• Define 'Ready for Operation': Ensure that the definition of 'completed' in the contract is equivalent to 'habitable.' Many disputes arise over 'grey areas' such as wall finishes or site preparation.

The contract sum is not a dictate, but an opening bid in a complex negotiation about risk distribution. Whoever understands the components controls the final result.