The most commonly-used frames for the various styles of greenhouses are steel, aluminum and wood, although some other options are available at varying price points. Concrete block, insulating concrete forms, poured concrete, brick or stacked natural stone could be used to form half walls, with glass or plastic film above. Traditional greenhouses were sometimes constructed with masonry walls, utilizing steel frame construction for the glass panels that comprised side walls and ceiling panels. These "conservatories" were often ornate and decorative. Modern greenhouses are typically more functional, constructed with economical and long-lasting aluminum frames and covered by clear or translucent plastic film or sheeting. They provide ample protection from most weather, but are not capable of withstanding extremely high winds, tornados or hurricanes.
Wood is often used for small, backyard greenhouses, and they too can be built with gabled roofs and plexiglass panels for a more substantial, finished appearance. They are attractive and functional for hobbyists. Do-it-yourself greenhouses, constructed of cast-off old windows, have become trendy in some areas, and constitute a functional recycling of materials joined together for a new purpose. Over time, however, wood is subject to deterioration caused by moisture and weather, so commercial greenhouses are seldom constructed of wood. A low-cost alternative is a DIY frame of plastic conduit, but it is not a viable option for long-term durability because PVC pipe and similar plastics will deteriorate from prolonged exposure to sun and weather.
