A builder constructed a house according to plans provided by the owner. The contract specified that only Reading brand pipe was to be used in the plumbing. After the house was completed, the owner discovered that another brand of pipe had been used. The owner refused final payment and demanded that the pipe be replaced with Reading pipe, which would have involved major reconstruction. Evidence at trial was that the two brands of pipe were of the same general quality. Did the owner have to make final payment, or did the pipe have to be replaced?