Undertaking construction work is often a leap of faith. There's the enthusiasm of "it's going to be impeccable," but also the fear of what might go wrong: delays, skyrocketing costs, materials different from what was agreed upon, rushed finishing touches, and seemingly endless arguments. It is precisely here that a construction contract makes all the difference. It's not a mere formality. It's the roadmap that transforms a vague promise into a concrete obligation and, when necessary, a clear path to demand corrections, reduce the price, or terminate the contract.

In this article, we explain what should be included in a construction contract, which clauses are most important, and what legal precautions to take before signing. The goal is simple: to protect the client and the contractor from misunderstandings and to create a solid foundation for resolving problems without drama, or with the right force when there is no alternative.

What is a construction contract?

A construction contract is an agreement in which the contractor undertakes to carry out a project and the owner undertakes to pay a price. The word "project" here is broad: it can mean building, remodeling, repairing, rehabilitating, installing a roof, redoing a bathroom, replacing window frames, or building a house from scratch.

In practice, a construction contract is used whenever the final result is what matters. It's not just about "working hours." It's about delivering a completed project that conforms to what was agreed upon.

This is particularly important in renovations and construction, because the risk of discrepancies between expectations and reality is high. And when the value is significant, the contract ceases to be "just a piece of paper" and becomes a form of protection.

What is the difference between a construction contract and a service contract?

Some might say, "it's just a service." But legally, it's not indifferent. In a construction contract, the focus is on the result. If the work has defects or doesn't correspond to what was agreed upon, a set of rights for the owner of the work and duties for the contractor come into play.

In service provision, the focus is on the activity. Simply put, you pay for the work done and not necessarily for a "finished" result.

In construction projects, this distinction influences everything: how the object is defined, how nonconformity is proven, what deadlines exist for reporting defects, and what legal solutions can be demanded.

7 legal precautions that save you trouble

Many disputes on construction sites arise before the work even begins. These are planning failures, not execution failures.

To reduce risk, there are seven precautions that are worth their weight in gold:

1. Full identification of the parties: name, tax identification number (NIF), address, and in the case of a company, identification of the company and its representative.
2. Confirmation of the contractor's technical and legal capacity: license or certificate when applicable, and proof of insurance.
3. Defining what is included and what is excluded: the "I didn't know it was separate" is a classic.
4. Detailed budget and work schedule: by specialty, materials and quantities, whenever possible.
5. Dates and milestones: start, phases, completion, and conditions for extension.
6. Record of communications: decisions are made in writing, not verbally amidst the chaos.
7. Inspection and acceptance: how each stage is validated and how the work is accepted.

If the work is related to a rented property, pay close attention to the contractual framework and permits. It may also be helpful to read: Works on the Leased Property.

Main clauses of a construction contract

A good construction contract doesn't need to be a textbook. It needs to be clear, verifiable, and useful when the first conflict arises. Instead of an endless list of points, it makes sense to focus on the clauses that, in practice, prevent conflicts on construction sites.

1) Project subject, measurements and finishing standards

If this part is vague, the rest of the contract is always weak. The construction contract should describe the work rigorously, ideally with annexes:

• Address and property identification.
• List of jobs by divisions and specialties.
• Reference to project plans, measurements and specifications, when available.
• Acceptable materials, brands or ranges and alternatives.
• Standard of finish, especially in paint, ceramics, carpentry and window frames.

2) Price, additional work, and rules for changes

The price must be clearly defined: a global price (per project) or a price per measurement (per meter, per unit, per bill of quantities). In either case, there is a rule that safeguards relationships: changes and additional work only proceed with written approval, a defined price, and an impact on the agreed-upon deadline.

If price revisions are involved (for example, in long-term projects), it is advisable to establish them from the outset:

• Under what circumstances does it apply?.
• What criteria are used?.
• How is the increase proven?.
• Limits and deadlines for communication.

This prevents the project from becoming a collection of uncontrollable extras.

3) Deadlines, schedule and consequences of delay

The construction contract must specify a start date and an end date. It is also important to define:

• What counts as a delay attributable to the contractor?.
• What justifies an extension (for example, changes requested by the owner of the work, licensing delays, proven external events).
• Is there a penalty clause for late payment, and how is it calculated?.

Well-designed penalties are not meant to "punish." They serve to prevent the work from being left in limbo.

4) Phased payments, invoices and withholding

This avoids the typical imbalance: either the client overpays before seeing results, or the contractor lacks the liquidity to proceed.

The most balanced approach is to define payments in phases, linked to objective milestones (for example, completed demolitions, completed installations, completed plastering, completed finishing). For projects of some scale, it makes sense to plan for:

• Issuing invoices and receipts.
• A percentage is retained and released after final payment is received and all outstanding issues are resolved.
• What happens in case of late payment and how to communicate this?.

When properly worded and proportionate, retention is one of the best guarantees that defects will be corrected.

5) Materials, supplies and replacements

Who buys? Who transports? Who is responsible for damages and storage? This clause seems simple, but it is one of the most contentious.

Define clearly:

• Who supplies the materials by specialty?.
• What happens if a material becomes unavailable?.
• Is it permissible to replace brands, and under what criteria (technical and aesthetic equivalence)?.

In renovations, this avoids arguments like "I put back what was there.".

6) Licenses, safety, waste and subcontracting

Not all construction projects require permits, but many do require prior notification, compliance with municipal regulations, and safety obligations. The contract should clearly distribute responsibilities and avoid surprises.

Include, where applicable:

• Who handles licenses and communications.
• Safety and health standards on the construction site.
• Waste and debris management.
• Condominium rules, schedules, and noise.
• Subcontracting: whether it is unrestricted or requires authorization, and, above all, whether the contractor retains full responsibility for the subcontractors.

When these obligations are not well distributed, the problem arises at the worst possible time: with deadlines and costs already on the table.

7) Inspection, communications and acceptance of the work

Oversight prevents two very common scenarios: the project progressing "in the wrong way" and the conflict erupting too late.

The contract should state:

• Who oversees this and with what powers?.
• How are decisions recorded (emails, messages, work minutes)?.
• How is the final inspection carried out?.

8) Defects, warranty, liability for damages and recourse in case of breach of contract

This is the clause that provides leverage when something goes wrong. The law provides rights to the owner of the work when there are defects, but what often decides the outcome is how the problem is reported and how quickly action is taken.

In practical terms, the contract should define:

• What is considered a defect and what is normal wear and tear?.
• How to file a complaint (in writing, which contacts to use, with what supporting documents).
• Response and repair times.
• What happens if there is no correction: price reduction, repair by third parties, contract termination.

To delve deeper with concrete steps, see also: Construction defects e Property Guarantee.

Private contracting and public contracting: they are not the same game.

If the project is with a public entity, the regulations change and there are specific rules, including procedural and execution requirements. If you work with public procurement, it is important to ensure the project falls under the applicable regulations. For more information on this topic, it may be helpful to read: Public Works and Contracts.

A well-drafted construction contract avoids litigation, but also provides leverage when needed.

The biggest advantage of a comprehensive construction contract is that it reduces disputes. It specifies what needs to be done, when, with what materials, at what price, and to what standard. And when something goes wrong, it provides the tools to act quickly.

If you need support in drafting, reviewing, or executing a construction contract, it may make sense to seek legal advice in the area of... Litigation, Civil Law and Enforcement Or, if you're on the business side, learn about the support for... Lawyers for Construction Companies.

Conclusion

A construction contract isn't meant to raise suspicions about anyone. It's meant to protect both parties when stress, time, and money are at stake. And in construction, they always are.

If you're going to proceed with a remodeling or construction project, the best time to prevent problems is before signing. A well-drafted construction contract clarifies the scope of work, sets the price, manages deadlines, defines how extras are approved, and provides a clear procedure for reporting defects.

If you already have a project underway and feel that something is getting out of control, don't wait for it to "fix itself." The sooner you have a strategy and effective communication, the better the chances of correcting the situation without escalating.

If you need help reviewing your construction contract, formalizing notifications, demanding corrections, or resolving breaches of contract, speak to a [legal professional/expert]. Solicitor and schedule an evaluation of your case through Contacts.