INDUSTRIAL FUMIGATION AGAINST INSECTS 7 



Old or poorly constructed buildings present a different problem. 

 Both walls and roof must be carefully inspected for cracks or breaks. 

 In certain types of roofs the union between the roof and the walls 

 may be faulty and need to be tightened (figs. 8 and 9). Any loose 

 flashing around chimneys and ventilators must be repaired, and 

 ventilators and skylights must be sealed over (fig. 8). In some cases 

 it is impossible to tighten a window by the ordinary method of 

 wedging and sealing or stripping, and the entire aperture must be 

 sealed over (fig. 9). For this purpose a fiber-reinforced waterproof 

 building paper is excellent. It can be obtained in rolls 300 feet long 

 and from 3 to 7 feet wide. It is a simple matter to tack it over 

 the opening, and the edges can be sealed down with adhesive tape. 



Figure 8. 



-Skylights and flashings on roof sealed in preparation for fumigation. 

 All ventilators must also be sealed. 



If this type of paper is not available, any good tough paper can be 

 used and can be applied by a paperhanger or any careful workman. 

 Even newspapers or old advertising posters will sometimes suffice if 

 several layers are used, but the best paper for fumigation purposes 

 is that impregnated with fiber and tar. 



Loosely fitting window sashes should be sealed with paste and 

 paper, or puttied up with a mixture of flour and oil. For stripping 

 windows that are only slightly loose several types of materials can 

 be used. Rolls of gummed paper, strips of newspaper smeared with 

 grease or pasted with flour paste, and rolls of unsterilized adhesive 

 or masking tape, known as "fumigators' tape," all have their place. 



Small doors leading to the exterior of the building can be tight- 

 ened by stripping around the edges with any of the materials used 

 for the windows. Large sliding or hinged doors that fit imperfectly, 

 or elevator-shaft openings, can be sealed most effectively by forcing 

 a framework of 2- by 4-inch lumber covered with fiber-reinforced 

 waterproof paper against strips of heavy felt padding (figs. 10 and 

 11). Such a sealing can be used many times. Another method is 

 to calk the doors with a paste composed of 4 parts of asbestos fiber 

 to 1 part of calcium chloride mixed with a little water. The calcium 

 chloride will absorb enough moisture from the air to keep the paste 

 pliable and thus insure a tight seal. It is a cheap yet effective seal- 

 ing material and can be easily removed after the fumigation. 



