Rastra

Rastra is a registered trade name associated with an insulating compound concrete form system, or ICCF, used to construct insulated building walls. The system combines structural concrete with a lightweight insulating form made from Thastyron, a cement-bound material containing a high proportion of recycled post-consumer expanded polystyrene. Unlike conventional removable formwork, Rastra blocks and panels remain in place after concrete is poured, creating a composite wall with thermal, acoustic, and fire-resistant properties. The technology has roots in the development of polystyrene concrete. Polystyrene concrete was invented in 1960, while the Rastra system was first patented in Austria in 1965 and entered production in 1972. The product was developed through the work of an Austrian-Swiss-based company that adapted the earlier material into a construction system. Rastra is therefore associated with one of the earlier commercial approaches to insulating concrete forms and with the creation of the term Insulating COMPOUND Concrete Form. Rastra blocks are manufactured in multiple sizes and can be cut with common woodworking tools to create openings, corners, curves, and other building geometries. Blocks or panels are joined with clamps or adhesive into a grid-like form. Reinforcing steel is placed within the grid, after which the cavities are filled with concrete. The resulting wall integrates insulation and concrete rather than treating them as separate layers. This construction method is intended for building envelopes and structural or infill wall applications, subject to applicable engineering requirements and building codes. A central part of Rastra's positioning is resource efficiency. The Thastyron component is described as containing approximately 85 percent recycled post-consumer polystyrene waste. The production process does not require energy-intensive curing, and the energy requirement is reported at approximately one to three kilowatt-hours for a block exceeding ten square feet. Trimmings produced when blocks are cut to final dimensions can be returned to production, reducing manufacturing waste. The referenced description states that the process releases no by-products considered an environmental burden. In use, Rastra walls are promoted for their insulation, thermal stability, sound reduction, durability, and fire performance. The material has low heat penetration depth and can moderate indoor temperature changes, potentially reducing heating and cooling demand. It is also described as resistant to frost, fungus, and mildew, with sound insulation above 50 decibels. Reported material values include a compressive strength of 56 pounds per square inch and a tensile strength of 43 pounds per square inch for Thastyron. The system is further described as having a four-hour fire rating with no flame spread or smoke development; a separate five-hour fire-endurance test on a ten-inch wall reportedly exposed the wall face to temperatures above 2,000 degrees Fahrenheit without heat conduction through the wall. Such performance claims are test-specific and should be assessed against local certification and code requirements. Rastra is best understood as a construction-material technology and trademark rather than a diversified consumer brand. Publicly available reference material identifies its product concept and technical characteristics but does not establish a current corporate owner, headquarters, executive team, public listing, or official corporate website.

Rastra belongs to the early history of insulating concrete form construction. The underlying material lineage reaches back to polystyrene concrete, which was invented in 1960. BASF, a German chemical company, originally developed polystyrene concrete but did not identify a successful application for it at that stage. An Austrian-Swiss-based company later modified the material and developed the system associated with the Rastra name. The Rastra system was first patented in Austria in 1965 and has been in production since 1972. Its development established a construction approach in which insulation remains part of the formwork while concrete is placed inside the form. The company or developers associated with the technology also introduced the term Insulating COMPOUND Concrete Form, abbreviated ICCF, to distinguish the system from other insulating concrete form concepts. The material known as Thastyron is central to the system. It consists of plastic foam, principally recycled post-consumer polystyrene, combined with a cementitious binder. The referenced technical description identifies recycled content of approximately 85 percent. Rastra blocks and panels are produced in different dimensions, then trimmed to specification. Offcuts and trimming debris can be recycled into new blocks, creating a closed-loop element within the manufacturing process. The production description also states that curing does not require energy and that manufacturing each block larger than ten square feet requires approximately one to three kilowatt-hours. In construction, the blocks are shaped with woodworking tools and assembled with clamps or adhesive into a grid. Reinforcing steel is inserted through the form, and concrete is poured into the resulting cavities. This creates a wall assembly in which the concrete provides mass and structural capacity while the surrounding Thastyron form provides continuous insulation. The system can be adapted to different wall shapes and building details, although design, reinforcement, concrete placement, and fire compliance remain dependent on project engineering and local regulations. Rastra's technical proposition has emphasized building performance as well as resource efficiency. The material is described as resistant to frost, fungus, and mildew and as having low toxicity. Its acoustic insulation is reported to exceed 50 decibels. Thermal performance derives from the insulating form, which reduces heat penetration and helps maintain more stable interior temperatures. The reference material also reports a four-hour fire rating without flame spread or smoke development, together with a five-hour fire-endurance test of a ten-inch wall exposed to temperatures above 2,000 degrees Fahrenheit on the face without heat passing through the wall. These figures describe reported tests rather than universal performance guarantees. Public reference information provides a technical history and product description but does not document a complete current corporate history. It does not identify a present headquarters, owner, executive roster, current distribution network, financial information, or official website. Accordingly, Rastra is documented here primarily as a construction-system trademark and material technology.

• 1972

  Rastra enters production

  [1]Rastraen.wikipedia.org

  The Rastra system begins production as an insulating compound concrete form product.

• 1965

  Rastra technology is patented in Austria

  [1]Rastraen.wikipedia.org

  The construction technology associated with the Rastra name receives its first patent in Austria.

• 1960

  Polystyrene concrete is invented

  [1]Rastraen.wikipedia.org

  Polystyrene concrete, the material precursor to the later Rastra system, is developed.

A sustainable insulating concrete form system combining recycled-polystyrene insulation with concrete construction for thermally stable, acoustically insulated, durable, and fire-resistant building walls.

• Insulating concrete forms · 1972

  Rastra insulating compound concrete form blocks

  Rastra blocks are lightweight, cement-bound insulating forms containing a high proportion of recycled post-consumer polystyrene. They are supplied in different sizes, can be cut with woodworking tools, and are assembled into a grid before reinforcement and concrete are added. The forms remain in place to provide continuous insulation around the concrete wall.

• Insulating concrete forms

  Rastra insulating compound concrete form panels

  Rastra panels extend the same ICCF principle beyond standard blocks. They are used as components of insulated concrete wall assemblies and can be arranged, trimmed, and joined to suit building layouts. Their role is to combine a permanent insulating form with reinforced, poured concrete.

• Cement-bound recycled insulation material

  Thastyron

  Thastyron is the material used to make Rastra forms. It combines plastic foam with a cementitious binder and is described as containing approximately 85 percent recycled post-consumer polystyrene. The material provides the lightweight insulating body of the blocks and panels while allowing production trimmings to be recycled.

1. 1Rastraen.wikipedia.org