Construction contract review in Switzerland: what to check
- Simon Käslin
- Jul 1
- 7 min read
Updated: 28 minutes ago
The construction contract and building specifications are the most important documents for your building project: they define what you will receive for your money. Nevertheless, many clients sign them without reviewing them, trusting that everything important is already included. This is precisely where the most expensive surprises arise.
Anything not clearly defined in the building specifications will later become a change order or be missing altogether. Having the construction contract and the building specifications reviewed before signing allows you to close these gaps while you still have negotiating power.
Table of contents
Is the construction contract on the table?
Negotiations are still possible before signing. An independent review will uncover any gaps in time.
1. What is a construction contract?
A construction contract is the agreement by which you commission a contractor to complete a project, such as building a house or undertaking a renovation. It regulates the scope of work, price, deadlines, warranties, and the obligations of both parties. Construction contracts are governed by the Swiss Code of Obligations (Art. 363 ff. CO).
The construction contract is therefore the foundation of your building project. Its contents are legally binding. Anything missing or unclear will be interpreted in the event of a dispute, often not in your favor. That's why a thorough review before signing is essential.
2. What is a building specification?
The building specifications describe exactly what will be built: materials, construction methods, finishing standards, and fixtures. They form the basis of the construction contract and define the agreed-upon standard. Everything listed in the building specifications is included in the price. Anything beyond that is an additional cost.
A good building specification is precise and complete. A poor building specification uses vague phrases like "high-quality materials" or "your choice," which later make almost every choice an extra cost.
3. How are the construction contract and the building specifications related?
The construction contract provides the legal framework, while the building specifications detail the specific content. Only together do they provide a complete picture of what you will receive. A clearly worded construction contract is of little use if the building specifications are incomplete, and vice versa.
Therefore, both documents must be reviewed together. The most frequent problems arise at the interface: the construction contract refers to the building specifications, but these leave key points open.
4. Why a construction contract review in Switzerland pays off
Before signing, you have negotiating power; afterward, you lose it. A review reveals what's missing, what's unclear, and where risks lie, as long as you can still request changes. Once signed, you're bound by the contract, and any correction becomes a negotiation or a change order.
The review is inexpensive relative to the contract price. It prevents you from receiving less for seemingly the same price or having to pay extra later through change orders. The article "Cost Control in the Construction Phase" discusses how to avoid additional costs during the construction phase.
5. What is important in the building specifications?
A good building specification leaves no questions unanswered. Pay particular attention to the cost-relevant and often vague points.
Are the materials and standards specifically named, not just listed as a budget item?
Are the quantities and qualities defined, not just "usual" or "as selected"?
Is it clear what is not included (scope demarcations, own work by the client, client-provided services)?
Are the surroundings, utility connections and ancillary costs covered?
The more specific the building specifications, the smaller the potential for change orders. The article "Sampling and Material Selection" deals with how the subsequent material selection process works.
6. What does SIA 118 mean?
SIA 118 is the standard for construction work and regulates the relationship between client and contractor, for example regarding the acceptance inspection, warranty rights, and deadlines. Many construction contracts in Switzerland refer to it. If SIA 118 is agreed upon, its rules apply in addition to the contract.
It is important to check whether and how SIA 118 is incorporated and whether individual provisions are modified. Such deviations are permissible, but may work to your disadvantage. The articles "Notice of Defects" and "Warranty and Defect Periods" explain how warranty rights and deadlines work.
7. Lump sum price or unit prices?
In a construction contract, the price is usually agreed as a lump sum price or via unit prices. With a lump sum price, a fixed amount is owed for a defined scope of work. With unit prices, billing is based on the quantities actually performed.
Pricing model | Billing | Cost risk for the client | When is it suitable? |
Lump sum price | Fixed amount for a defined scope of work | Low, provided the building specifications are complete | Clearly defined project |
Unit price | Based on the actual quantity × unit price | Medium to high | If quantities are still unclear |
Overall price (GC/TC) | Fixed price for the entire scope of work | Low, but check the standards carefully | Turnkey solution with a general or total contractor |
The agreed-upon model determines your cost risk. Ultimately, the completeness of the building specifications remains crucial.
A fixed price provides security, but is only as reliable as the building specifications. If the scope of work is incompletely described, additional charges will arise despite the fixed price. The rule is therefore: the price is only as good as the building specifications on which it is based.
8. What are the pitfalls of a construction contract with a general contractor?
When working with a general contractor, the building specifications are particularly important because they define the entire scope of work. Common pitfalls include low standards, numerous open budget items, unclear scope demarcations, and clauses that restrict warranty rights.
Which procurement model suits you best is discussed in the article "General Contractor, Total Contractor, or Individual Trade Contracts." Especially with a general contractor, it's important to remember: an attractive fixed price is meaningless until the building specifications have been reviewed.
9. What are the most common typical mistakes?
The most common mistake is signing a construction contract without reviewing it, either out of trust or due to time constraints. Equally common is focusing solely on the price and overlooking the scope of work.
A third mistake is accepting vague wording in the building specifications. Anything that remains unclear will later be interpreted against you. Clarity before signing is the best protection.
10. Three practical examples
Practical example 1: The vague building specification
The building specifications consistently used phrases like "high-quality" and "your choice." Almost every subsequent choice of materials resulted in an additional cost. A review before signing would have clarified the standards.
Practical example 2: The restricted defect rights
In a construction contract, the warranty rights in relation to SIA 118 had been tacitly amended to the detriment of the client. This only became apparent during the review process, and the clause was corrected before signing.
Practical example 3: The missing scope demarcation
A fixed price seemed attractive, but the building specifications left the surrounding area and utility connections undefined. These items were later billed separately as change orders. With a clear demarcation of these items, the price would have been comparable and transparent.
11. Frequently asked questions about the construction contract and building specifications
What is the difference between a construction contract and a building specification?
The construction contract establishes the legal framework, including price, deadlines, and warranties. The building specifications describe the specific details, such as materials, construction methods, and standards. Only together do they provide a complete picture.
Should I have the contract reviewed before I sign it?
Yes. You have negotiating power before signing, but not afterwards. A review will uncover gaps and risks as long as you can still request changes.
What should be included in a good building specification?
Specific materials and standards, defined quantities and qualities, clear demarcations of what is not included, as well as rules on the surroundings, utility connections and ancillary costs.
Is a fixed price in a construction contract safe?
Only to the extent that the work is described in the building specifications. If the specifications are incomplete, additional charges will apply despite the lump sum price. The price is only as reliable as the building specifications.
What does SIA 118 regulate?
SIA 118 is the standard for construction work and regulates, among other things, the acceptance inspection, warranty rights, and deadlines. Many construction contracts refer to it. It is important to check whether individual provisions have been modified to the detriment of the client.
What do I need to pay attention to when signing a construction contract with a general contractor?
A complete building specification with clear standards, few open budget items, clear scope demarcations and clauses that do not restrict warranty rights.
12. How raumwert plus supports the review
A construction contract review in Switzerland requires experience that private clients rarely have. raumwert plus reviews the construction contract and the building specifications as a neutral party before signing, identifies gaps, and assesses whether price, scope of work and risk are aligned.
This ensures you sign with full knowledge of what you are receiving. The framework is provided by the owner advisory service from raumwert plus. This article explains the principles and does not replace legal advice in individual cases.
Is the construction contract on the table?
Negotiations are still possible before signing. An independent review will uncover any gaps in time.
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