CHAPTER VII 

 GLAZING AND PAINTING 



Greenhouse glazing is an art in itself. 

 Most construction firms employ professional 

 glazers. It is, however, an art that may be 

 readily acquired. Many owners do their 

 own glazing when occasion requires, or have 

 it done by their ordinary help. The method 

 of glazing greenhouse roofs is not the same 

 as that used in glazing window sash. When 

 glazers from glazers' shops or hardware 

 stores are employed, precaution should be 

 taken to see that they understand the differ- 

 ence. 



Glass. The glass commonly used in 

 greenhouse glazing is clear, white, sheet or 

 window-glass of either A or B grade. Glass 

 with a pronounced green or bluish cast is to 

 be avoided, as it obstructs a large part of the 

 heat, light and chemical energy of the sun's 

 rays. 



Clear, white window-glass ordinarily ab- 

 sorbs about 30 per cent, of these rays ; green, 



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