Contractor's Unilateral Substitution of Foundation Constitutes Fundamental Breach

A contractor, having agreed to construct a building according to plans that specified the use of a particular type of foundation, substituted a different, less robust foundation without the owner's knowledge or authorization, leading to structural defects after completion. The owner sued for breach of contract and damages, arguing the substitution constituted a material defect in execution. The court ruled in favor of the owner, holding that the contractor's unilateral deviation from the contractually agreed-upon specifications, especially concerning a critical structural element, constitutes a fundamental breach of the obligation to perform the work as stipulated, regardless of whether the substitution meets a minimum technical standard, thus justifying rescission of the contract and compensation for damages.