Legal Maxims in Construction Contracts
Latin maxims are shorthand for rules that decide real money on construction projects. Mutatis mutandis carries a main contract's terms into a subcontract. Contra proferentem decides who loses when a clause is ambiguous. Lex non cogit ad impossibilia separates a performance that is impossible from one that has merely become expensive. Quantum meruit pays for work done when there is no contract price to rely on, and the prevention principle stops an employer holding a contractor to a date the employer itself made impossible.
This guide collects CALIM's explanations of each maxim and doctrine from the contractor's side of the table: what the words mean, how tribunals apply them, where the governing law changes the answer, and what a commercial team should do on site so the principle works for it rather than against it.
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Frequently asked questions
Why do construction contracts still use Latin legal maxims?
Because each maxim names a settled rule of interpretation or liability in a few words. Contracts and correspondence use phrases such as mutatis mutandis to import a whole set of terms, and tribunals use maxims such as contra proferentem to resolve ambiguity. A contractor who understands what the phrase does can see the risk it carries before signing, instead of discovering it when a claim is assessed.
Do Latin maxims apply to GCC contracts governed by civil law?
The Latin labels come from Roman and English law, but many of the underlying ideas appear in the civil codes of the GCC in their own terms, including rules on interpreting ambiguous terms, on performance that becomes impossible and on unjust enrichment. What matters is whether the governing law contains the rule and how its courts apply it, so the governing law clause is always the first thing to check.
Can a contractor rely on a legal maxim instead of the contract terms?
Rarely as a first line. Maxims help a tribunal interpret the contract or fill a gap, but express terms usually prevail, and notice provisions and time bars still apply. The safer course is to use the contract's own mechanisms first, such as extension of time, variation and claims procedures, and to treat the maxim as support for that position rather than a substitute for it.
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