Editing Geodesic dome (section)

==Methods of construction==
[[File:Long Island Green Dome.jpg|thumb|Long Island Green Dome]]
Wooden domes have a hole drilled in the width of a [[strut]]. A stainless steel band locks the strut's hole to a steel pipe. With this method, the struts may be cut to the exact length needed. Triangles of exterior plywood are then nailed to the struts. The dome is wrapped from the bottom to the top with several stapled layers of [[tar paper]], to shed water, and finished with shingles. This type of dome is often called a hub-and-strut dome because of the use of steel hubs to tie the struts together.

Paneled domes are constructed of separately framed timbers covered in plywood. The three members comprising the triangular frame are often cut at compound angles to provide for a flat fitting of the various triangles. Holes are drilled through the members at precise locations and steel bolts then connect the triangles to form the dome. These members are often 2x4s or 2x6s, which allow for more [[Building insulation|insulation]] to fit within the triangle. The panelized technique allows the builder to attach the plywood skin to the triangles while safely working on the ground or in a comfortable shop out of the weather. This method does not require expensive steel hubs.

Steel framework can be easily constructed of electrical conduit. One flattens the end of a strut and drills bolt holes at the needed length. A single bolt secures a vertex of struts. The nuts are usually set with removable locking compound, or if the dome is portable, have a [[castellated nut]] with a [[Cotter (pin)|cotter pin]]. This is the standard way to construct domes for [[jungle gym]]s.

Domes can also be constructed with a lightweight aluminium framework which can either be bolted or welded together or can be connected with a more flexible nodal point/hub connection. These domes are usually clad with glass which is held in place with a PVC [[Coping (architecture)|coping]], which can be sealed with silicone to make it watertight. Some designs allow for double glazing or for insulated panels to be fixed in the framework.

Concrete and foam-plastic domes generally start with a steel framework dome, wrapped with chicken wire and wire screen for reinforcement. The [[chicken wire]] and screen are tied to the framework with wire ties. A coat of material is then sprayed or molded onto the frame. Tests should be performed with small squares to achieve the correct consistency of concrete or plastic. Generally, several coats are necessary on the inside and outside. The last step is to saturate concrete or polyester domes with a thin layer of [[epoxy]] compound to shed water.

Some concrete domes have been constructed from prefabricated, prestressed, steel-reinforced concrete panels that can be bolted into place. The bolts are within raised receptacles covered with little concrete caps to shed water. The triangles overlap to shed water. The triangles in this method can be molded in forms patterned in sand with wooden patterns, but the concrete triangles are usually so heavy that they must be placed with a crane. This construction is well-suited to domes because no place allows water to pool on the concrete and leak through. The metal fasteners, joints, and internal steel frames remain dry, preventing frost and corrosion damage. The concrete resists sun and weathering. Some form of internal flashing or caulking must be placed over the joints to prevent drafts. The 1963 [[Cinerama Dome]] was built from [[precast concrete]] hexagons and pentagons.

Domes can now be printed at high speeds using very large, mobile "3D Printers", also known as additive manufacturing machines. The material used as the filament is often a form of air injected concrete or closed-cell plastic foam.

Given the complicated geometry of the geodesic dome, dome builders rely on tables of strut lengths, or "chord factors". In ''Geodesic Math and How to Use It'', [[Hugh Kenner]] wrote, "Tables of chord factors, containing as they do the essential design information for spherical systems, were for many years guarded like military secrets. As late as 1966, some 3''ν'' icosa figures from ''[[Popular Science (magazine)|Popular Science Monthly]]'' were all anyone outside the circle of Fuller licensees had to go on." (page 57, 1976 edition). Other tables became available with publication of Lloyd Kahn's ''Domebook 1'' (1970) and ''Domebook 2'' (1971).