FRAMEWORK 83 



bars. Metal sash bars, as before mentioned, 

 seldom prove satisfactory. The framework 

 of such houses is practically indestructible, 

 and when the woodwork decays it can be re- 

 placed upon the old framework. 



Usually the weakest part of a greenhouse 

 is the gable. It should be well framed and 

 securely tied to the purlins and other parts 

 of the framework. 



METHODS OF ERECTION 



Foundations and Walls. In the old-style 

 high, solid wall greenhouse, the wall was a 

 source of much perplexity, especially the 

 high north wall of the uneven span house. 

 In modern houses, however, the solid wall is 

 seldom higher than the top of the benches, 

 when benches are used, or only a few inches 

 above the surface when plants are grown on 

 the ground. The remaining part of the side- 

 wall is constructed of posts and glass, thus 

 giving more light. The chief difficulty with 

 the high, solid wall was that the extremes of 

 temperature between the outside and inside 

 in cold weather caused them to disintegrate 

 rapidly. This was particularly true with 

 masonry walls. 



