314 



ENGINEERING ON THE FARM 



Pitch. The pitch of a roof is an important matter in 

 determining the type of roof covering. The pitch of a roof 

 is designated as the ratio of the perpendicular height of the 

 ridge above the plate to the width of the building. For 

 example, if a building is 24 feet wide and the ridge is 8 feet 

 above the plate, the pitch of the roof, then, is %24, or y$. 

 Shingles should not be used where the pitch is less than %. 

 Valleys. In designing roofs, it is highly important to 

 eliminate, as far as possible, all valleys. In the case of 

 heavy snowfalls the valley is a receptacle for much snow. 

 This begins early to melt, run down, and be caught in the 

 heavy depth of snow in the valley, and there frozen. Later 

 meltings cannot get by, and these are backed up the slope 

 of the roof. The final result is the damming of the melting 

 snow until it runs up under the shingles, tile, or slates of the 

 roof, to appear on the ceiling or walls or rooms below in large, 

 permanently discolored areas. Where it is impossible to 

 avoid valleys, much trouble may be avoided by use of an 

 extra-wide valley tin. The ordinary widths are very satis- 

 factory in rainy weather, but are entirely too narrow in 



regions where heavy 

 snows are encoun- 

 tered. 



Gutters. It is de- 

 sirable to hang 

 gutters on all eaves 

 in order that the 

 roof water may be 

 led either to a cis- 

 tern or to a waste- 

 way, thus prevent- 

 ing a heavy down- 

 pour of water in 

 close proximity to foundation walls. The type of gutters 

 which has the least number of shortcomings is the hang- 

 ing or molded gutter. A box gutter lined with metal 



Fig. 257. Typical open cornice, eave, 

 and gutter {desirable) 



