HOME BUILDING AND WOOD PRESERVATIVES 



577 



exception of fence posts, and therefore must resort to the 

 open tank or brush methods of treatment. The former 

 consists in dipping or otherwise immersing the wood in 

 open tanks containing the preservatives, and allowing it 

 to remain from a few minutes to several hours, accord- 

 ing to its condition and the kind of wood. By the use 

 of alternating hot and cold baths, either by removing the 

 timber from the hot bath to the cold, or by allowing the 

 hot solution to cool to air temperature, a much greater 

 penetration is obtained than if a hot solution alone is used 

 Detailed information on the kind of tanks to build an ! 

 use, and the various steps in the open tank treatment are 

 obtainable from publications of the United States Forest 

 Service at Washington, and from the circulars of com- 

 panies which sell preservatives. Whatever the instruc- 

 tions given or the processes used, it is very essential that 

 the wood be thoroughly air seasoned before treatment. 



The brush treatment is in effect a thorough painting of 

 the wood with hot creosote, which should be applied with 

 a large brush and in liberal amounts so that all cracks 

 and openings may be filled and the outer surface im- 

 pregnated to the full hmit of absorption. It is often ad- 

 visable to apply two or more coats, allowing the first 

 to dry before the others are applied. The life of inferior 

 timbers, which decay quickly, can be increased to equal 

 or e.xceed that of more durable species untreated. But no 

 treatment will be effective on rotten or defective timber 

 and it will not hide or cure defects. 



Preservatives have no appreciable effect on the strength 

 of wood, and posts, sills and similar timbers may be used 

 the same as if untreated. The exception is found in the 

 case of pressure treatment where the wood is given a 

 steaming process at high temperature in order to remove 

 the sap, but this would not be encountered by the home 

 builder. 



Creosote will burn, but after it is dried into the wood, 

 a stick will not ignite any more readily than if untreated ; 

 in fact, tests on thoroughly treated structural timbers in- 

 dicate that while it will burn with a hot flame and a heavy 

 smoke, it chars more quickly and is less likely to burn 

 entirely through than if untreated. Mineral salts, on the 

 other hand, have very distinct fire resisting qualities, 

 and thereby serve a double function. 



Light-colored paints cannot be applied over the surface 

 of creosoted wood, but creosote itself gives an attractive 

 brown stain, and for barns and other buildings of similar 

 character, it takes the place of paint. As a matter of fact, 

 the timbers around the usual home which are mostly in 

 need of treatment, such as sills, the under side of porch 

 flooring, the foundation timbers, etc., are not visible, and 

 can be creosoted without detriment to the appearance of 

 the structure. Creosote is distinctly valuable in checking 

 insects, and is accordingly particularly useful for chicken 

 houses or to guard pig pens against infection with hog 

 cholera. 



There is a very rapidly increasing use of preservatives 

 on wood shingles, and the practice is to be highly com- 



USES OF WOOD PRESERVATIVES 



Top Treating fence posts by the open tank process, the posts 



being first shaved with a draw knife so the preservative 



easily penetrates the wood. 

 Second Lumber for sills and foundations being treated with 



refined creosote applied by a power spray. 

 Third In building a chicken coop the lumber is first treated 



with refined creosote applied much like ordinary paint. 

 Fourth A barn stained with refined creosote the result a 



handsome brown effect unaffected by rain or sun. 



