The careful estimator will study out not only the plumbing specifications but will likewise read through the general conditions of the general specifications to see if there is anything there which affects the plumbing work. He will look in the mason's specifications, also, to see if the digging of trenches and other excavating called for in his specifications is likewise specified to be done by the mason. In many specifications this conflicting condition is required and the wide-awake estimator who discovers it can take advantage of the conflicting requirement and estimate accordingly. To do so, however, he must first ascertain from the architect which of the contractors, the mason or the plumber, will be required to do the work, for the mason contractor might have had a decision from the architect to the effect that the plumbing contractor will do his own excavating, in which case omitting that item from the estimate would entail loss on the plumbing contractor. Even if the architect should decide that all excavating work for the plumber shall be done by the mason, care must be exercised by the plumbing estimator. If the plumbing specifications are corrected by the architect upon making that decision, all is well; but if no indication or correction is made in the specifications, to protect his own interests the plumbing contractor will either have to estimate on doing the excavating and trust to luck to get out of it, or he can omit the item from his estimate, and, in submitting his bid, state explicitly that it does not include excavating, calling attention at the same time to the provision in the mason's specifications.

In like manner the estimator should examine the carpenter's specifications to see if that contractor is to do his cutting of walls, floors and beams; and the steamfitter's specifications to see if there is a conflicting statement regarding the water-heating apparatus or other parts of the plumbing work. In the case of cutting of walls, floors and beams, this is assumed to be the plumber's work, if nothing is said to the contrary, for the plumbing work cannot be installed without the necessary cutting and patching. Plumbers usually make such a botch of the cutting and repairing work, however, that many architects prefer to have it done by the carpenters. In such cases, the work is specified to be done by the carpenters, and, as it is only implied in the plumbing specifications, but not stated, the requirement in the carpenter's specifications makes it part of his contract. That being so no mention of the cutting and patching need be made in the plumber's tender, while the advantage he gains by reading the carpenter's specifications and learning that work he would otherwise figure on is to be done by another, gives him a slight advantage over his competitors, and the sum of all the slight advantages should secure him the contract.