The other materials are the polycarbonate, in this case a multi-wall, multi-wall polycarbonate, which
offers higher impact resistance and heat retention over thinner panels. The panel offers 79% light
transmission and includes anti-condensate coating to prevent dripping. It also has UV inhibitors that
prevent the material from yellowing. (Megastore, n.d.)
A third option that could be considered is the glass covering. It has a pleasing appearance, is inexpensive
to maintain, and has a high degree of permanency. An aluminum frame with a glass covering provides a
maintenance-free, weather-tight structure that minimizes heat costs and retains humidity. Glass is
available in many forms that would be suitable with almost any style or architecture. Tempered glass is
frequently used because it is two or three times stronger than regular glass. The disadvantages of glass
are that it is easily broken, is initially expensive to build, and requires much better frame construction
than plastic. A good foundation is required, and the frames must be strong and must fit well together to
support heavy, rigid glass.
Polycarbonate, glass, and Solexx, all offer a good amount of insulation as well as heat retention, but even
with them we need to find alternative ways of heating the greenhouse in order to save energy.
Taking in consideration our constraints, the plastic film can be easily destroyed, does not have a long life
expectancy, and it is also not strong enough to hold the weight of heavy snow, these cons would
increase the work to change it every year or so. The glass is easily breakable and expensive, these two
cons are enough to eliminate it from the possible materials. Fiberglass has more or less the same
yellowing problem as plastic film and acrylic is not resistant enough.
This leaves two choices, the multiwall polycarbonate or Solexx. They are impact resistant, they have a
large life expectancy, and both of them, normally, come with a 10-year warranty. It is also good to
remember that, for aquaponics, the greenhouse does not have to be made of transparent material from
top to bottom, normally just from the top of the beds and up, and for this particular greenhouse, one
wall can be entirely made of wood, since it will not get sunlight.
2.3.1.4 Floor
There are many different options to choose from when deciding what kind of material should be used
for the floor in a greenhouse. For a regular hydroponic greenhouse, it is common to have the floor made
out of dirt with walk ways around the vegetables made with industrial tiles. However, for an aquaponics
system the vegetable do not grow in the ground and a stronger foundation is required in order to
support the weight of the beds and tanks.
Aquaponic system also differs from hydroponics in the point that there will always be a lot of indirect
water flowing and spilling on the ground, where in hydroponics there will be a certain amount of water
usage directed to the same points and absorbed by the ground.
With this reasoning, most people think that concrete, or a brick foundation are the best options for the
flooring of a greenhouse, but in reality they are not ideal and quite costly. Because we are dealing with
water and organic products, concrete and bricks could cause problems within the greenhouse, problems
like harboring mold and disease.
In the other hand we have a floor made of dirt, which costs little to nothing and, in time, absorbs the
water, but since it takes time, and the water will make a mess inside of the greenhouse a dirt floor is far
from ideal.