6 



CIRCULAR 369, U. S. DEPT. OF AGRICULTURE 



make it reasonably gastight. Doors leading to the outside should be 

 sealed (fig. 7). Ventilators on the roof (fig. 8) or outside walls 

 should also be sealed over, and any windows that are not tight 

 should be sealed around the edges. 



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 be- 

 tween the roof and 

 the walls may be 

 faulty and need to be 

 tightened ( figs. 8 

 and 9). Any loose 

 flashing around 

 chimneys and venti- 

 lators must be re- 

 paired, and ventila- 

 tors 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 strip- 

 ping, and the entire 

 aperture m u s t be 

 sealed over (fig. 9). 

 For this purpose a 

 fiber-reinforced wa- 

 terproof 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. If this type of 

 paper is not avail- 

 able, 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. Kolls of gummed paper, strips of newspaper smeared with 



Figure 7. — Doors to warehouse, and transom, sealed with 

 old advertising posters cut into strips. Latticed ware- 

 house doors in warm climates can be effectively sealed 

 with three or four thicknesses of such material. 



