Buildings and Yards. 



567 



be entirely rigid, but that if ends of four lath are united into a square by 

 use of a single nail at each angle the structure has no rigidity. Persons 

 are often at a loss to know whether they have a true truss. The answer 

 to the query is whether they have three sides of a triangle properly 

 fastened together. 



In building plank barns, the width of the material makes it possible to 

 use nails in fastening the ends in place of mortise and tenon, which were 

 necessary with square timbers. This very much reduces the amount of 

 labor and requires somewhat less skilled labor. In building plank barns, 

 two difficulties have sometimes arisen : the nailing has not been sufficient 

 to stand the pull ; and sufficient provision has not been made for lateral 

 pressure. 



Fig. 341. — JMcthod oj trussing roof. Truss is i //. by 8 in. hard tcood let into 

 upper surface of rafters and securely nailed to each rafter. 



AV['. Appearance 



Were it possible to define exactly what it is that gives to structures 

 satisfactory appearance, or, as we say, a proper architectural efifect, there 

 would not be so many unsightly buildings. Some things that contribute 

 to this effect are adaptation to purpose and surroundings, appearance of 

 strength, durability, good workmanship. 



Nothing should be placed on the outside or inside of a building that 

 does not have a use or meaning. In addition to first expense, it adds to 

 the cost of maintenance. Strength and durability cost money, but money 

 expended for the purpose of producing striking efiects would, if ex- 

 pended on good construction, bring better architectural results. 



