Summary of Jacob v. Kent
Ct. App N. Y. 
Relevant Facts: Pl built a country residence for the Df. Construction work ceased and the Df began to occupy the dwelling. 1 yr later the Df complained of a defect in performance. Under the K specific material was agreed upon. The Df learned that some of the pipe was the product of other manufacturers. The Pl was directed by the architect to do the work anew. The plumbing was encased in the walls and obedience meant more than substitution, it meant demolition of substantial portions of the completed structure. PL left the work untouched. Evidence supported the contention that the omission was neither fraudulent or willful. The Df’s architect failed to notice the discrepancy despite his inspection of the pipe.
Legal Issue(s): Whether the contractor, who rendered substantial performance, should pay the cost of replacement, or the difference in value for trivial or innocent omission of a contract condition?
Court’s Holding: Difference in value.
Procedure: Trial ct judgment for Df entered upon a directed verdict, PL appeals. Order of the App Div reversing judgment for defendant entered on verdict directed by the court and granting new trial, defendant appeals. Order affirmed and judgment absolute directed in favor of plaintiff.
Law or Rule(s): An omission, both trivial and innocent, will sometimes be atoned for by allowance of the resulting damage, and will not always be the breach of a condition to be followed by a forfeiture.
Court Rationale: Where by inadvertence or mistake a minor deviation has been made, which involves no damage to the Df, and df takes possession of and continues to use the building.without seeking to disturb in any respect the work done by the contractor, the contractor is entitled to prove that he had substantially performed, that the Df suffered no damage through such innocent mistake, and that what the owner received is what he had the right to expect to get under his contract. We must weight the purpose to be served, the desire to be gratified, the excuse for deviation from the letter, the cruelty of enforced adherence. Then only can we tell whether literal fulfillment is to be implied by law as a condition. Where the significance of the default is grievously out of proportion to the oppression of the forfeiture, the law will be slow to impute the purpose of the performance, in the silence of the parties. The measure of damages is not the cost of replacement, but the difference in value, which would be either nominal or nothing. The owner is entitled to the money which will permit him to complete, UNLESS the cost of completion is grossly and unfairly unproportional, then the measure is the difference in value.
Plaintiff’s Argument: Pl substantial performed under the K, the replacement parts were identical in quality, and nature, apart from the difference in manufacturer.
Defendant’s Argument: The K condition which the Pl was a party to, specified Reading, and the Pl used Cohoe.