If we were to apply to the normal statute of limitations of three years[8] the extension which G.L.c. 260, § 12, affords, the latest the plaintiffs could have brought a tort action was within three years after they received the Tsiang report dated August 12, 1975. From that report the plaintiffs learned that their house suffered from a serious foundation defect, even if they may have been uncertain of its precise extent and nature. See Mansfield v. GAF Corp., 5 Mass. App. Ct. 551, 555 (1977). It will be recalled that the plaintiffs did not file their action until August 7, 1979. Conscious of that hurdle, the plaintiffs, after substantial discovery, filed with the court an election to abandon all actions other than those "based upon contract under seal." They did not, however, opt for rescission, a contract remedy that is available as an alternative to a tort action for deceit, although generally in circumstances where there has been only partial or relatively recent performance of the contract. See Forman v. Hamilburg, 300 Mass. at 142; Geoffrion v. Lucier, 336 Mass. 532, 537 (1957); McMahon v. M & D Builders, Inc., 360 Mass. 54 (1971); 12 Williston, Contracts § 1523 (3d ed. 1970). Cf. National Academy of Sciences v. Cambridge Trust Co., 370 Mass. 303, 309 (1976). Actions for rescission must be brought with reasonable promptness. 12 Williston, supra, § 1526, at 622. Cf. Restatement *639 (Second) of Contracts §§ 164 and 380 (2) (1979). Rather, the plaintiffs argue that since the defendants' alleged misrepresentation served to induce the plaintiffs to sign the purchase and sale agreement as an instrument under seal, they may sue for damages on the basis of the misrepresentation at any time within twenty years of the performance of that contract.