This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
Disputes often arise over the meaning of contracts after they are made and perhaps reduced to writing. This may come from careless drawing; it may be due to the necessity of applying the contract to new and unforeseen circumstances, or it may arise from a desire of one of the parties to a controversy to strain every point in his own favor. When such disputes arise it is an important matter for the parties to know how the proper construction is determined.
If the question of the construction of a contract is involved in a litigated case, the matter is determined by the judge, not by the jury. There are many rules of construction by which the judge is guided, only some of the more general and the more important of which will be mentioned here. While no oral evidence to explain or supplement a written contract will be heard, yet the judge may consider other distinct agreements of the parties which modify the contract in question. He will also hear evidence as to the circumstances of the parties when the contract was made, as tending to show the meaning of expressions used. Oral evidence may also be given to show the technical, and sometimes the customary, meaning of words contained in the contract. When, how--ever, a custom is relied upon to give to a word a meaning different from that generally accepted, or to add to the substance of a contract, it must be a custom that is reasonable, certain, defined, and uniform. In most cases the custom must be shown to be known to both parties to the contract. It is important in framing contracts to use words in general use, and to use them in a commonly accepted sense, seeking clearness and precision, and carefully avoiding possible ambiguities. In construing a contract, the object of the court is to ascertain the real intent of the parties at the time of signing. The judge seeks to decide what meaning the words had as used by the parties, under the given circumstances, at the given time and place. In construing any portion, he takes the whole instrument into account, and looks for such an interpretation as will give effect to every part.