Greenhouse Structural Components (2024)

Chapter 1

The greenhouse is a structure made by assembling different parts or components. Each part has specific role in greenhouse structure. The main components of a greenhouse are its structural components like trusses, purlins, and side posts. Most frames are made from steel, aluminum, plastic, or wood. There are several materials to consider when deciding the kind of foundation to use for the greenhouse. Wood timber, concrete or concrete block, and brick are all suitable choices. The covering material of the greenhouse, also known as glazing, is usually the most expensive component of the structure. It is also one of the most important because the glazing is what allows the entry of light and heat into the greenhouse.

Greenhouse Framing Members

Trusses are the fundamental vertical support structure of a greenhouse (See Figure 1.14), which supports the weight of the roof. They provide strength to the basic structure and a hence placed at a distance of 2, 3, 4 feet or as required. The truss is made up of rafter, strut, and chords. Struts are support members under compression while chords are supports members under tension. Trusses are connected by the roof ridge and the purlins which run the length of the greenhouse.

Greenhouse Framing Materials

There are number of structural parts of a greenhouse roof which include bar caps, gutters, purlins, trusses, ridge cap, sash bar, and sideposts. Bar caps are attached to the outside of the greenhouse sash bars to hold the glazing material in place. The bar caps also hold the glazing compound used to seal around the glass (or other glazing material) to prevent leaks. The bar caps shield the glazing compound from the ultraviolet rays.

Greenhouse Foundation

When setting up a greenhouse, one of the most important aspects of the construction process is the foundation. There are a few different types of foundations that can be used for greenhouses. The type of foundation used is determined by the style of greenhouse and building codes. Essentially, the foundation is the complete system on which the greenhouse structure sits. One of the key components of a foundation is the footing. The footing refers to the point at which the structure meets the soil.

Greenhouse Walls

The end and side walls are typically covered with one of the rigid plastics. The structured acrylics and polycarbonates will provide heating costs can be gained. better insulation and security against theft or vandalism, but at greater initial costs, than fiberglass. Since the structured plastics come in 8- or 10-foot panel lengths, less cutting and splicing will be needed in comparison to polyethylene which comes in a minimum of 20-foot wide rolls.

Greenhouse Flooring

Growers may choose from a range of floor surfaces for container grown crops from gravel to concrete. The actual floor design will be dependent upon the type of production being planned and the available capital.

Soil Floors

Soil floors are rarely found in large greenhouse operations, except for small-scale vegetable operations. Muddy conditions due to irrigation, roots growing into the soil, and. the challenge of controlling weeds make this practice hard to manage unless the soil is naturally very well drained.

Gravel Floors

One of the simplest floor systems is a gravel floor. In this case plants are grown on a pad of 3/8 inch crushed rock or pea gravel. This is a low-cost floor production system and the gravel allows for excellent drainage. However, weeds may grow in the gravel and sanitation can be difficult on gravel floors. It may also be difficult to have small containers sit upright and level on gravel floors.

Concrete Floors

Concrete floors are very common with commercial greenhouses. In part because of environmental legislation that requires growers to capture drainage and runoff, and also to accommodate mechanization equipment and general cleanliness. Where concrete is used, it should be slightly sloped to allow water to drain off. Concrete floors prevent weeds and are generally easy to clean. They are durable and long-lasting and provide the advantage of maximizing space usage efficiency as well as flexibility. There are two basic types of concrete that may be used for greenhouse floors.

Floor Drainage. Although there is generally very little excess water on a concrete floor, sloping the floor to a drain is important. A slope of 1/8-inch per linear foot is usually the standard.

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