Traditionally, glass is among the more popular options. It transfers light well, is reasonably simple to clean and has first-class reflective properties that contain the heat produced. However glass is transparent, heavy, costly and is susceptible to breakage. Extreme variations in both inside and outside temperatures can cause spontaneous cracking while accidentally knocking the glass can cause it to shatter.
As a result, and coupled with advances in materials technology over the last twenty years or so, more greenhouses are using plastic and composite materials for the roof.
Plastics can be bought that are either totally transparent or semitransparent. In climates that have long summer hours of direct light and less cold winters, a translucent roof helps to control the amount of sunshine
Of course, there is nothing to stop you using glass in the roof since it is possible to invest in one of several choices of shading system. There are reasonably priced mechanical systems that use white cloth, bamboo or plastic shutters. If you want to spend a little more, there are even systems that will sense the amount of sunlight entering and electrically open and close the shades.
Walls are the next key consideration when building your own greenhouse. Once again, glass has traditionally been used and offers the same advantages and challenges as the roof. Additionally though, the walls or sides also have to bear the weight of the roof. Most are embedded or alternated with some form of load-bearing rods, beams or other supporting materials.
A glass greenhouse or glasshouse as they are sometimes referred to, can be a beauty to behold. However, modern-day plastics and composites can also furnish a lightweight, strong and attractive alternative. Some are even partially wood, aluminum and other materials, although these are more often used only on the lower half. There is not much point in building a greenhouse that does not let light in since that is just a shed!
Choosing a material for your greenhouse floor calls for some consideration, as well. Wooden floors are cheap to build and replace as required. However, they do not have the temperature control characteristics offered by cement, which traps heat and re-radiates it later on in the day as the temperature cools off. Decide on something that affords good drainage and will last through several winters.
When choosing materials for building your own greenhouse, consider sunlight and heat control, the needs of the type of plants you intend to house and your own comfort. You will want something you can enjoy spending hours a day inside of.