SCREENING 199 



length of the step as may be. This may be done by having folding doors 

 one best to stay fastened, or by moving the whole single door to the left 

 and fill in the space to the right by screening. The reason is that one 

 always goes up about the middle of the steps, and, if the door opens from 

 the ends of the steps, the person entering, after beginning to open the 

 door, steps down a couple of steps so as to get out of its way, thus open- 

 ing the door more widely and holding it open longer than advisable." 



SOME GENERAL RULES 



The following general rules in regard to construction and 

 installation of screen doors are given by Snidow: 1 



1. "To prevent warping, the frame should be made of substantial, 

 carefully selected, light-weight material, well-braced with iron brackets 

 at the corners. In order to add a double protection against sagging, a 

 wire support should be drawn diagonally across the lower half. This 

 may be accomplished by use of a double wire attached loose, then 

 tightened with a turn-key until the desired tension is reached. 



2. "The section of screen wire covering the frame should be cut 

 sufficiently large to allow a lap of Y± inch all the way around, and should 

 be tacked on firmly with tacks not more than 3 inches apart. After- 

 wards, molding strips should be nailed on, covering edges of wire and 

 tack heads. 



3. "The lower half of the door frame should be covered on the 

 inside with a reinforcing section of the so-called hardware-cloth, a 

 coarse, substantial wire screen with about a quarter-inch opening 

 between the meshes. This will protect the bottom panel of the door 

 from kicks and the carelessness of children. 



4. "A light strip of wood, about 3 inches broad, should be nailed 

 across the door frame at about the height of a man's shoulders. This is 

 to push against when opening the door. 



• 5. "A satisfactory spring should be used to insure the door remaining 

 tightly closed against the battens when not in use. 



6. "Two hooks or catches should be provided, one about half-way up 

 to the top section of the closing side of the frame, and the other near the 

 bottom. The top catch may be used alone during the day, but at night 

 both should be fastened. This will help to prevent warping. 



7. "In fitting screen doors in the door frames, no attempt at edge- 

 fitting should be made. The door should be made to fit against a%-inch 

 batten all the way around the inside, and sufficient space should be 

 allowed around the edges and the frame for the door to swell in wet 

 weather without scraping at the bottom." 



1 Transactions of the First Annual Conference of Sanitary Engineers, 

 U. S. Public Health Service, 1919. 



