ANTI-CONDENSATION ROOFING 241 



In Fig. 125, an eave purlin is used and a channel is placed along 

 the ends of the purlins. Spiking strips should always be used as shown, 

 and the eave purlin should be fastened to the rafter by means of angle 

 clips. 



The finish shown in Fig. 126, was used by the U. S. Government 

 and needs no explanation. 



Anti-condensation Roofing. To prevent the condensation of 

 moisture on the inner surface of a steel roof, and the resulting dripping, 

 the anti-condensation roofing shown in Fig. 127 and in Fig. 129 is fre- 

 quently used. The usual method of constructing this roofing is as 

 follows : Galvanized wire poultry netting is fastened to one eave purlin 



mS i ^ 



Pou/fry Nettfng 



Anti-Condensation Roofing 

 FIG. 127. 



and is passed over the ridge, stretched tight and fastened to the other 

 eave purlin. The edges of the wire are woven together, and the net- 

 ting is fastened to the spiking strips, where used, by means of small 

 staples. On the netting are laid one or two layers of asbestos paper 

 I- 1 6-inch thick, and sometimes one or two layers of tar paper. The 

 corrugated steel is then fastened to the purlins in the usual way. 

 Stove bolts, 3-16" diameter, with I x ^ x 4-inch pilate washers on lower 

 side, are used for fastening the side laps together and for support- 

 ing the lining (see Fig. 129). The author would recommend that pur- 

 lins be spaced one-half the usual distance where anti-condensation lin- 

 ing is used ; the stove bolts could then be omitted. Asbestos paper 1-16- 

 inch thick comes in rolls, and weighs about 32 pounds per square of 100 

 square feet. Galvanized poultry netting comes in rolls 60 inches wide 

 and weighs about 10 pounds per square. 



The corrugated steel used with anti-condensation roofing should 

 never be less than No. 22, and the purlins should be spaced for not less 



