This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
If one who has agreed to construct a building performs the contract substantially and makes a bona fide effort to comply with its terms, slight defects in his work and slight deviations from the contract will not prevent him from recovering the contract price, less the amount that will be necessary to make the building conform to the terms of the contract.1 On the one hand the owner cannot terminate the contract for slight departures from its terms,2 and on the other hand the contractor cannot recover the entire contract price without any abatement for the expense of making the work conform to the contract.3 Thus a slight deviation from the plans caused by a mistake in measurement, not discovered by either party or the architect until the contract is completed, and not affecting the external appearance of the house or its usefulness, does not prevent the performance from being substantial.4 So a contract to furnish glass for a house is performed substantially where, of over a hundred panes, all but two are perfect, and those two are defective in a way not uncommon in glass of that kind.0 So a contract to decorate the walls of a room, do the wood-work and provide furniture for five thousand two hundred dollars is performed substantially where everything is done according to the terms of the contract except the woodwork ; and the defects in that can be remedied for five hundred dollars.6 So a contract for plumbing is substantially performed where the only defects are in certain connections which can be completed for a small part of the contract price, even though the system is useless as he left it.7
4 Wilcox v. Assurance Society. 173 N. Y. 50; 93 Am. St. Rep. 579; 65 N. E. 857.
5 Lahey v. Lahey, 174 N. Y. 146; 95 Am. St. Rep. 554; 61 L. R. A. 791; 66 N. E. 929. (An action between the former beneficiary and the new beneficiary.)
1 Harlan v. Stufflebeem, 87 Cal. 508; 25 Pac. 686; Healy v. Fallon. 69 Conn. 228; 37 Atl. 495; Palmer v. Britannia Co., 188 111. 508; 59 N. E. 247; Keeler v. Herr, 157 111. 57; 41 N. E. 750; Cook v. Luxfer Prism Co.. 93 111. App. 299; Wagner v. Allen. 174 Mass. 563; 55 N. E. 320: Scheible v. Klein. 89 Mich. 376; 50 N. W. 857; Feeney v.
Bardsley, 66 N. J. L. 239; 49 Atl. 443; Oberlies v. Bullinger. 132 N. Y. 598; 30 N. E. 999; Nolan v. Whitney, 88 N. Y. 648; Woodward v. Fuller, 80 N. Y. 312; Phillip v. Gallant, 62 N. Y. 256; Ashley v. Henahan. 56 O. S. 559; 47 N. E. 573; Kane v. Stone Co.. 39 O. S. 1; Goldsmith v. Hand. 26 O. S. 101; Aldrich v. Wilmarth, 3 S. D. 523; 54 N. W. 811; Anderson v. Harper, 30 Wash. 378; 70 Pac. 965; Lay-cock v. Parker, 103 Wis. 161; 79 N. W. 327.
2 West v. Suda, 69 Conn. 60; 36 Atl. 1015.
3 Keeler v. Herr, 157 111. 57; 41 N. E. 750.