When a ready mix concrete firm submits a bid to a contractor or owner, his per-cubic-yard bid or proposal may be based on someone else's estimate of the volume of work or materials required. On occasion, the ready mixer runs the risk of a quantity underrun which greatly increases his per unit costs. On the other hand, if there is a quantity overrun, the ready mixer may receive the benefit of lower per unit costs. The question remains how the risk of underruns or overruns can be fairly shared between the purchaser and the supplier. Over the years, the courts have developed several legal rules to deal with this type of situation. They can be summarized as follows:

  1. OBVIOUS ESTIMATING ERRORS-- Where there is a blatant error in the invitation for bids, the contractor may not be allowed to take advantage of it.
  2. OWNER'S DISCLAIMERS--Regarding underruns, many standard contracts have provisions disclaiming any responsibility for estimating quantities.
  3. Are such provisions enforceable? The general answer is "yes." However, there are some limitations on enforcing these disclaimers. Where the purchaser either is careless about disclosing accurate data or he misrepresents the actual site conditions, a court may decline to enforce a contract provision.