STRUCTURAL MATERIAL 



71 



cold weather they become so cold as to cause 

 the moisture in the air inside the house to 

 condense rapidly on them, which results in a 

 large amount of drip. Various types of bars 

 have been invented in an attempt to over- 

 come these difficulties. 



Fig. 40. Two types of patented metal sash-bars 



Wood sash bars are not good conductors 

 of heat and condense but little moisture, but 

 moisture from the glass finds its way to the 

 sash bars, so that they are usually made 

 with a groove or furrow on each side, which 

 conducts the moisture down to the eaves. 

 The most common size of wood sash bars is 

 iH x 2 J /2 inches. Larger bars are used for 

 special purposes. 



