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.
The primary object of this paper is instruction; and there are introduced here certain problems carried along lines which show the particular qualities of the material under consideration. Special attention is called to the fact that these problems are not introduced merely to illustrate the qualities of the particular material, but to indicate lines of thought to be followed in considering every material.
There are a great many things taken for granted in connection with building material - many old beaten paths which lead one from tradition to nowhere. The sooner the specification writer accustoms himself to testing everything he handles, the sooner he will be master of the situation. If this work is ignored, and he follows only beaten tracks - and the information of "Material Men" - he will be in hot. water most of the time.
In specifying materials, one maxim should always govern: Never specify a quality which you cannot demonstrate exists, or forbid a quality or ingredient you cannot detect. For instance, if you are not prepared to have a chemical analysis made of the Portland cement don't say anything about sulphur or magnesia; clauses of this kind may sound well, but they may cause you trouble if later you cannot tell anything about the composition of the material. If you depend on the analyses as made by the manufacturers, You can depend on it that you will never find a cement with a harmful percentage of either.
The problems will be on the following subjects - Sand, Cement, Lumber, Roofs.
In addition to the work along the lines laid out, the powers of observation should be so cultivated that in the daily routine, wherever work is encountered, the eye will be ever ready to detect any phase of development in material.