Some construction contracts expressly warrant “good workmanship.” Even if that is not expressed, New Hampshire law “recognizes an implied warranty that the contractor or builder will use the customary standard of skill and care," Lempke v. Dagenais, 130 N.H. 782, 794 (1988). In either case, the warranty is that the work will meet the standard of care applicable to the building trades―that threshold level of quality we think of as acceptable construction.
Building codes may prescribe the standard of care for some aspects of construction, but these codes are generally safety oriented, and don’t address everything. Efforts to define the standard where the code is silent―when something should be deemed out of square or out of plumb, what fraction of an inch will be deemed “within tolerance” for some given aspect of the work, and so on―have occasionally been attempted (the National Association of Home Builders’ Residential Construction Performance Guidelines comes to mind). But no written set of rules governs every possible situation. Like Justice Potter Stewart’s famous “I know it when I see it” comment on the difficulty of establishing a legal test for obscenity, substandard construction is often easier to spot than to define.
Meeting this threshold standard of care will not always produce a satisfactory result for the customer. The parties are free to agree on something more, and many express warranties do go further, warranting that materials used will be of a given quality, that a particular result will be achieved, or that the end result will be structurally sound. (The one-and-only statutory warranty I am aware of, RSA 356-B:41, II, is of this type, providing that the declarant of a condominium “shall warrant or guarantee, against structural defects, each of the units for one year from the date each is conveyed, and all of the common areas for one year.”) In such a case, meeting the standard of care won’t be enough; the builder must do what he promised, and repair or replace the warranted item regardless of whether the work was otherwise up to industry standards.
Whether they are express or implied, warranties don’t last forever; they have a particular duration, and if a problem with the construction arises during that time frame, the builder is legally bound to make it good. Notice that I said “arises,” not “is discovered.” If the warranty period runs out before a problem is discovered, but the owner can prove that it actually arose earlier (although nobody noticed at the time), the builder is still on the hook. Our Supreme Court said in Terren v. Butler, 134 N.H. 635, 639 (1991), in commenting on the condominium structural warranty, “We do not construe the one-year life of the statutory warranty to be a statute of limitations or even a time limit on the delivery of effective notice. The one-year period describes the life of the duty, that is, the period during which breach may occur.” Chances are good that the same analysis will apply to contractual warranties of good workmanship.
The length of an express warranty is a matter of negotiation. Most express warranties I have seen recite a one-year duration. Implied warranties last “a reasonable time,” and depending on the circumstances that could be more than a year―which is why I usually recommend to my builder clients that they specify a one year period for a warranty of good workmanship rather than roll the dice on how long a court might think the implied warranty lasts. (As I said before, if they are on the same subject, the express warranty will override any implied warranty.)