Dome greenhouse (or, as it is also called, geodesic) is one of the most spectacular structures that are being erected on a summer cottage. Such a structure is made in the form of a hemisphere, and the frame is assembled from triangular segments. In addition to the attractive appearance, such greenhouses have a number of operational advantages and are most beneficial for growing plants throughout the year.
Benefits of Dome Greenhouses
Dome greenhouse has the following advantages:
- Round greenhouses are distinguished by the highest strength and stability, far superior to the usual types familiar to all. The streamlined design with a wide base allows it to withstand strong storms.
- The advantage of such structures is high seismic stability. It is provided by the sectional type of structure, which evenly distributes the forces acting on it and significantly weakens them.
- An important advantage of domed greenhouses is the ability for a long time indoors to maintain a temperature favorable for plants without additional heating. This effect is provided due to the spherical shape of the structure. During the day, the air warms up, rises and fills the entire dome space. At night, it is forced out by a cold stream, which directs warm air down to the plants. In the afternoon, the sun again heats the soil through the transparent roof and walls, which in turn transfers heat to the air. Thus, air circulation occurs, providing a favorable microclimate inside the greenhouse.
- Inside the domed greenhouse there is never a lack of lighting, because the sun's rays freely penetrate into it from all sides.
- Thanks to the domed shape, up to 30% of the internal space is saved.
- The greenhouse dome is very mobile, as it consists of triangles that can be easily assembled and disassembled. The main thing is to ensure that the length of all elements is the same.
- Economic benefit: the consumption of protective material is the lowest among greenhouses.
- The domed greenhouse (photo attached) has a beautiful and decorative look - in fact, it is the decoration of the site.
- One of the main disadvantages of dome structures is the limited size. It’s impossible to place many beds inside such a greenhouse and it’s not very convenient to work, since it’s almost impossible to stand in full growth. This problem can be solved by increasing one of its main parameters - diameter.
disadvantages
- It will not work to grow tall plants, so the dome greenhouse is not functional enough.
- The complexity of the device shelving on the gentle and rounded walls of the dome.
- The design of such greenhouses is very complex. Making calculations and assembling it with your own hands is not so simple (but possible). It consists of polygonal and triangular frames, which are not always possible to make at home, so they have to be ordered somewhere on the side, and this leads to an increase in the cost of the entire structure. In this case, you can use the assembly of ready-made domed greenhouses. Their frame consists of metal profiles and is very quick and easy to assemble.
Now let's move on to the most important thing - the creation of such structures. First of all, it should be noted that a domed greenhouse can be made of plastic pipes, metal profiles, wooden bars, etc., that is, from any improvised materials.
DIY domed greenhouses
Despite the complexity of the design, it is quite possible to make dome greenhouses with your own hands. It is important to understand that in general the design consists of a network of triangles that are interconnected at a certain angle and in a certain order. A greenhouse with a massive dome, despite its large bearing capacity, should have additional supports around the frame perimeter - load-bearing beams.
Polycarbonate Dome Greenhouse
Such structures are considered the most popular, since this material is more durable than polyethylene. To use glass for sealing greenhouses of this type is extremely irrational due to its high cost and high weight. However, this material benefits in durability and transparency.
Materials and tools for the construction of a domed greenhouse
For construction, you will need:
- Wooden blocks or metal beams of the same length.
- Polycarbonate or other protective material (polyethylene, glass).
- Connecting elements necessary for the assembly of the frame (self-tapping screws, steel strips, washers, screws).
- Roulette, level, spade.
- Shiny material for covering the dome of the northern part (for example, foil).
Dome greenhouse: calculation in stages
The main task in calculating the dome is to obtain the following data for a given radius:
- total area and height of the structure;
- the surface area of the dome;
- length and number of ribs;
- size of intercostal angles;
- type and number of connectors.
To calculate the dome, you must first determine the size of the future design. It must be borne in mind that the base area of the finished product will be less than the area of the circle, since the base contains a polyhedron inscribed in a given circle.
The height of the dome is determined by the length of its diameter. It may be:
- for an even partition height of 1 \ 2, 1 \ 4, 1/6 of the diameter;
- for odd - 3/8, 5/8.
The higher the greenhouse, the more the design will resemble a ball.
The surface area of the structure is calculated by the following formula: S = 4 π * R2.
For a dome that is half the sphere, use the formula S = 2 π * R2. If it is necessary to calculate the area of a sphere segment , apply the formula S = 2 π * RH, where H is the height of the segment.
To calculate the necessary structural elements, you can use the online calculator. It is enough to enter data on the height and radius of the dome, and the service will calculate, give out the number and length of ribs, the number and type of connectors.
The length of the ribs can also be calculated independently using coefficients, and it is better to entrust the calculation of the number of materials with a calculator.
The best option for a domed polycarbonate greenhouse is the height is 1/2 diameter. Such a hemisphere is the easiest to assemble and convenient to operate. According to the calculations of the geodetic calculator, for the assembly of a structure 2 m high and 4 m in diameter, you will need:
- 35 elements of a triangular shape, the rib length of which is 1.23 m;
- 30 elements with a rib length of 1.09 m.
The calculator offers a color scheme, according to which it is very convenient to assemble the dome.
Preparation of materials
According to the data obtained, material for construction is manufactured. As the connecting elements, it is better to choose a galvanized material that is resistant to corrosion. Particular attention must be paid to the dimensional accuracy of all parts.
After the bar blanks are ready, strips of steel 2 mm thick are cut. In them, at the same distance from each other, seven holes are drilled for self-tapping screws.
Frame assembly
When assembling a spherical structure, 3 types of connecting nodes are used:
- Quadrangular elements in which the long sides correspond to the length of the ribs of the frame, and the short ones correspond to the height of the base of the greenhouse;
- 5-coal - this is the main part of the geodesic dome. Collect them from triangular elements;
- Hexagonal elements.
Steel strips are bent at an angle of 250 ° so that 3 holes remain on one part and 4 on the other.
Frame Assembly Steps:
Do-it- yourself polycarbonate dome greenhouse is assembled as follows:
- A place is being prepared for the greenhouse, marking is being carried out. The site is leveled and covered with geotextiles to prevent weed germination. Gravel filling is done.
- The base of the domed greenhouse, consisting of quadrangular elements, is being installed. Each of them is fixed on the ground with metal arcs or brackets.
- According to the color scheme issued by the geodetic calculator, pentagonal elements are mounted from triangular elements. The assembly is carried out in this way: first, in a circle, the elements of the lower tier are connected together, and then they move to the upper one.
- In the upper part of the frame, several window leaves are made.
- For covering the polycarbonate greenhouse, preliminary preparation of the material is necessary - cutting into triangles of appropriate sizes.
Arrangement of the inside of the domed greenhouse
On the north side, the inner space of the hemisphere is glued with foil material. In the center of the greenhouse, a container of water is installed that can be used to water plants.
If the greenhouse is designed for year-round operation, pipes of the heating system are laid along its walls. For the circulation of air in the room using a conventional electric fan.
The beds, if desired, can be arranged in several tiers. The optimal width of the passage is 1-1.5 m.
Instead of a water tank, a beautiful exotic tree can be placed in the center of the hemisphere, and a table with chairs can be set against the wall. Thus, the greenhouse dome will turn into a very comfortable place to relax, which reliably protects from bad weather.