Why has the height of the gutter (eave) of greenhouses gradually ...

[nelaaney]

Why has the height of the gutter (eave) of greenhouses gradually increased from 8 feet to the current 14-16 foot height?
 
  What will be an ideal response?

Question 2

What were the situations or advantages which convinced some owners to use FRP in the past as a greenhouse covering?
 
  What will be an ideal response?

[cassie_ragen]

Answer to Question 1

The higher headroom inside the greenhouse allows for more uniform
temperature control inside. The extra height is required to accommodate one or
two layers of hanging baskets and equipment that has become popular such as
thermal/sun shade/ black out screens, supplemental lights, and air circulation fans.

Answer to Question 2

1) The initially high transmission of light through FRP compared to
glass or polyethylene during the dark months of the year. 2) The uniformity of
light intensity throughout an FRP greenhouse. Greater resistance to hail and
vandal damage. 3) The adaptability of FRP to temporary greenhouses otherwise
covered with film plastic such that the labor of covering is reduced. 5) Reduced
cooling requirement compared to glass greenhouses.

[nelaaney]

Excellent

[raili21]

Gracias!