PREFACE.

For a number of years the writers have been making a study of industrial problems and have been publishing the information which they have acquired, regarding the value of various structural materials, for the benefit of consumers as well as producers. The Institute of Industrial Research has received so many requests recently for information in regard to just what paints should be selected for the protection and decoration of houses and other buildings that it has seemed best to sum up the subject in the form of a special pamphlet or bulletin. It is only after years of investigation work carried on by the authors, both separately and in co-operation, that any review of the work has seemed possible, for only recently have the results of tests carried on in a number of different localities seemed to justify a definite opinion in regard to the best selection of exterior paints. No attack on any one paint material is here included, but the value of each has been carefully weighed, and the attempt is made to discuss them in the light of experience and knowledge. It is the authors' intention in this bulletin to put into the hands of architects and paint users who may not be thoroughly familiar with the technical properties of paint materials, information which will enable them to make a proper and intelligent selection of paints for the preservation and decoration of the exterior of wooden buildings.

The Preservation of the Exterior of Wooden Buildings

Lumber and its Relation to Paints: The proper choice and treatment of lumber is one of the most important problems which the builder as well as the painter has to face. When about to build a dwelling, barn, or other structure made principally of wood, the question is sure to arise in regard to what variety to select so as to get the maximum service and money value. The locality in which the structure is to be built must often have a bearing upon this question. While it is true that the painting of each type of wood demands the special consideration of the painter, it is also true that the study of paints for wood protection points toward the production of a paint that will give satisfactory results under all conditions and on all grades. It is the writers' opinion that a paint may be made that will be perfectly well suited for the preservation of every species of wood, provided the paint is properly treated in the hands of the skillful and intelligent painter, who can produce lasting results on almost every type by varying the proportion of thinners and oil in the various coats. The painter who uses the same paint on soft pine, and again on hard pine, without making a special study of how to reduce the priming coat for the hard pine, will be likely to get inferior results on the latter. In case of failure, the natural impulse is often to place the blame upon the paint, whereas the real responsibility may rest upon the painter's lack of knowledge.

Note.—For a more detailed account of the lumber question, see "Modern Lumber as a Problem for the Painter," read by John Dewar, at the Convention of Master House Painters' and Decorators' Association of Pennsylvania, January, 1911, Pittsburg, Pa.