Modular Building Systems

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Subcategory from our page on Open Source Manufacturing Tools, a draft structure and collection proposed by Eric Hunting.

Modular Building Systems: (here I've put in some descriptions from my work on the T-slot Sourcebook. This is an example of how the fabrication and engineering sections would be fleshed-out)

Matrix/Box Beam/Grid Beam - Modular building system invented by designer Ken Isaacs in the 1950s based on square holed wood, aluminum, or steel struts/beams joined with 'trilap' bolted joints and using a scalable regular geometry. One of the earliest deliberately open source building systems.

- How To Make Your Own Living Structures by ken Isaacs - The Box Beam Sourcebook by Richard Jergensen

Holed Profile - Construction based on tubular, 'L' shaped, and flat allow struts with regularly spaced holes. Though the technology is public domain, geometries are not standard from one manufacturer to another, though some are compatible with the geometry of Matrix. Popularized with the classic building toys Mechano and Erector Set. Commonly used for laboratory equipment, prototype machines, and simple home-brew construction before being supplanted by T-Slot.

Plate Frame Systems - Plate frame systems are most commonly seen in the electronics industry today but had their origins in the engineering of watches, clocks, and other gear-based mechanical systems and are commonly employed as the basis of electronics and machine 'chassis' structures, though they have often been employed in other uses and have featured in such things as novel furniture designs. They are based on the use of rigid plates of alloy, wood, plastics, and composites which are formed into stacks through the use of pins, posts, or blocks held in place by screws. This structure forms the basis of a frame holding static and movable components between the plates which, through the use of holes and surface-mounted fittings, hold parts in place from one or two sides. In electronics plates are usually formed of composite circuit board materials -and in earlier times materials known as 'phenolics' or 'phenolic composites' such as the well known Bakelite. In mechanical systems such as clocks alloys are the norm and may often be cut with openings for variably sized parts held in multiple stacks or to minimize weight or simply to create 'reveals' of the works for decoration. In decorative or educational machines such as 'visible' clocks clear plastic plates are sometimes used. Not strictly a true modular building system in the past, the use of plate materials with regular quadratic hole grids have sometimes been employed, particularly for the prototyping of electronics circuits and for some construction toys based on the technology. Though greatly declining in use in machine design in the late 20th century, it has seen a revival specifically in the maker movement as a result of the limitation of many early fab tools to cutting sheet material, thus inspiring new invention with plate frame designs.

Rod & Clamp Framing - Currently typified by its use as a framing system for the RepRap open fabber, this very old modular building system has obscure origins, possibly originating earlier than even the 19th century and may have derived from early scientific instrumentation. Very likely the origin of the concept of ball socket space frames. Based on the use of blocks with holes that clamp rods in place using a set-screw, the angle and placement of holes on the blocks determine the type of joint with 'trilap' joints supporting box frame structure common but with endless other possibilities such as octet and geodesic space frames. Blocks are typically equipped with additional fittings to support other components or cladding panels but rods can also be used to attach lighter objects or cladding using clips or simple 'C' clamps. Rods and blocks can also be used as parts of linear actuators and are sometimes precision ruled and engraved with ruling lines to allow for precision adjustable sliding elements. Produced with an endless assortment of materials but works best with alloy rods and alloy, plastic, or wood blocks and is usually limited to small light structures.

Pipe Fitting Systems - Possibly a derivative of Rod & Clamp systems, this common modular building system originated in the early 20th century and today has numerous producers worldwide. Popularized in the US under the brand name KeeKlamp. Public domain as a technology, but without an open source or public domain component set. Pipe Fitting Systems combine common galvanized pipe normally used for plumbing with sets of modular cast steel joints that clamp the pipes in place using a hex nut. Commonly used for institutional hand railing, playground equipment, industrial shelving, and greenhouse structures as well as many home-brew and temporary structures. Experimented with by Ken Isaacs in the 1960s as the basis of external support superstructures for lighter habitat structures.

Space Frame Systems - Appearing early in the 20th century, these systems were a particular fascination for Modernist designers but have never lived up to their early promise of being cheap and ubiquitous due to the inability -or refusal- of manufacturers to standardized on components across the industry. Used for everything from building toys to the largest clear-span buildings in the world, space frames are used as space-filling structures often based on octet geometry, planar trusses used for roof and floor decks, and as space enclosure systems such as the classic geodesic sphere or dome. Though once characterized as symbolic of Machine Age efficiency and expected to become ubiquitous, all commercial architectural uses of the technology to date have been based on manufacture-on-demand at outrageous cost premiums. Space frame systems come in the following types;

Ball Socket: uses nodal joints based on precision fabricated alloy balls with screw sockets that interface to screws on the ends of tubular alloy struts. The most common form of commercial space frame, popularized by the German Mero corporation. Often considered the strongest of the space frame joint schemes, typically only available as standardized off-the-shelf parts for very light systems used for kiosks and indoor store displays. Also considered the most sophisticated of space frame systems, it can employ the broadest range of materials for struts, including wood, plastic, FRP, fiberglass and carbon fiber composites, high-strength ceramics, and even solid wood or laminates. Even super-pressure pneumatic membrane struts have been used with this. Can be highly decorative with various anodized or powder coat treatments of parts or the use of wood or wood veneer over struts. The high precision needed for ball socket fabrication has long been a barrier to hobbyist or home-brew use of the type.

Novum (formerly Mero) -

Cast Socket: uses nodal joints based on cast or milled alloys to which struts attach by bolts perpendicular to the strut. Very often uses square or rectangular tubular profiles for struts, offering more cladding options over ball socket systems but at a cost in aesthetics. Also often uses modular units for nodes to simplify their fabrication and allow for some variation of geometry from a smaller set of parts. Easier to fabricate than ball socket but still challenging for home-brew development.

Crimp and Clamp: Specific to the use of enclosure space frames such as geodesic domes and to the use of light alloy tubular struts, is based on crimping the ends of struts then rolling their flattened ends to create a precision angled pin that is clamped in slotted tubular or solid cylinder node joints. Has the great advantage of reducing the node parts to simple standard shapes but the crimping and rolling of the struts tends to limit them to malleable steel alloys and highly stressed the metal, leading to potential fatigue failures that limits its use to light structures. Very common for playground domes and tent domes.

Plate Node: The simplest of space frame systems, is based on stamped alloy nodes that hold struts by perpendicular bolts. Largely the same as cast sockets save for the use of flat plate alloy that is stamped, folded, and rolled into the necessary shapes and sometime based on multiple pieces in order to sandwich struts between two or more plates for increased strength. Very commonly used for home-brew geodesic domes, is very commonly employed by DIY builders and is one of the few types that can effectively use wood as a strut material, thus it is standard for wood framed dome home products.

Plate Module: A departure from traditional systems and a derivative of plate truss systems, plate module systems employ plates as both node AND strut, using a large triangulated piece of flat material that interfaces to others, often with the use of an alloy plate or other interface. Plates are often fashioned with an open space in their inner area but are also used 'closed web'. The approach is typified by the Fly's Eye Dome devised by Fuller but can be stronger when used as the basis of box trusses and planar truss structures. Typically based on stamped alloys, it can also use common sheet materials like plywood. Has recently been studied as the basis of robotic self-assembling space frames based on equipping each plate modular with active components that allow them to climb over each other and link into place with powered locking hinges.

Glue Socket: A recent invention intended to find ways of using bamboo as a strut material in space frame structutres, glue socket space frames are inspired by classic wooden construction toys. Wooden blocks are precision milled to form nodal joins with hole sockets similar to ball socket nodes but shaped more like cast nodes. Struts of wood, engineered lumber, or bamboo are then inserted into the sockets and a high performance adhesive is pressure-injected into the socket to glue the strut permanently in place. High natural uniformity is necessary when using bamboo members.

Tensegrity: First devised by Kenneth Snelson but often wrongly attributed to Buckminster Fuller who adopted the concept as an expression of his Synergetics concept, this class of space frame structures is based on combining tension cables and rigid struts in self-tensioned networks where struts join only to tension cables. One of the most sophisticated of space frame types, their full potential remains unexploited despite being well suited to Maker experimentation. Introduction of nanofiber cable materials is likely to see great expansion of this form of structure.

N55 Space Frame - A unique variant of 'L' profile based holed profile systems using specially formed galvanized steel struts bolted together at nested ends to create and octet space frame structure. Can integrate roto-molded/blow-molded polyethylene containers also designed by N55 and open source. N55 Space Frame has a relatively high parts count for its structures but has been used to produce large and complex structures including buildings, floating platforms able to support buildings, suspended/hanging platforms, pontoon boats, and an endless variety of machines, furniture, and even sculptural objects.

Modular Wooden Post & Beam - The oldest of modular framing systems with examples thousands of years old, this building system is typified by preindustrial architecture but is not exclusive to architectural uses. The most refined of the traditional Post & beam systems may come from the Japanese tradition with housing based on the 'ken' system of modularity based on the dimensional standards of tatami floor matting. Japanese architecture and furniture were often a source of inspiration to early Modernist designers. Wooden Post & Beam framing is usually based on simple rectilinear geometry and employs wooden posts and beams with integral carved wooden tongue & groove joint elements locked with sometimes hidden wooden pegs. Contemporary systems have employed steel plate secured by bolts. X and Y axis posts typically must employ different planes to interface at common posts, but Japanese and more contemporary joinery have sometimes overcome this limitation. Despite its age and natural modularity, no true standardized mass-produced systems have ever evolved. The Japanese systems came closest to realizing this before being supplanted by western building system with industrialization. Many modular systems have been developed on a per-design basis, but not as a generalized building system, though no technical obstacles exist for this. The chief obstacles for its common use today are the high skill required for fabrication of its joinery, the increasing scarcity and cost solid lumber of large dimensions, and the high mass of its components as architectural scales.

Modular Block Masonry - Traditional block masonry, originating with the adobe block, is a very ancient building technology with the production of such blocks often considered the first form of mass production industry. But while such blocks are inherently modular themselves, this form of building has not often been regarded as a modular building system owing to the lack of direct interface between blocks. Adhesive mortar holds brick/block walls together, thus masonry has typically been seen as a means to create monolithic structures from small units. However, in the 20th century the ability to machine-produce blocks with much higher precision than before has lead to the use of direct block-to-block mechanical interfacing intended to reduce or eliminate the need for mortar in construction. This has also expanded the range of materials and uses for this beyond the architectural. However, as with many other forms of modular building, no definitive standard systems have ever evolved and one is usually limited to systems designed by a particular block manufacturer. Typified today by the construction toy Lego, modular block systems are characterized by the reliance upon a mechanical interface between blocks to hold them together rather than any kind of glue or mortar -though these may be used to create a water-proof seal- and the use of blocks of different shape to support the varying topology and features of a structure. Blocks may fit together in multiple planes of interface like the pieces of a jigsaw puzzle or they may rely on a separate system of tie-rods, bolts, or pins which link them together. Traditional materials such as earth, clay, concrete, and stone are common -since this is still dominated by architectural uses- but many more materials are now used such as engineered lumber, engineered (cast) stone, gypsum composites, ceramics, cast and molded glass, shaped alloy profiles, and plastics. Recently, the use of blocks featuring active robotic systems allowing for self-assembly of structures and machines have been explored among robotics designers. Though a public domain technology in general, the only modular block systems to get close to an open source building system standard have been precision compressed earth block systems such as the Auram system. (

FRP Frame & Panel - A very recently introduced technology, FRP frame and panel systems are based on the use of fiberglass reinforced pultruded plastics extruded in systems of self-interlocking posts, beams and corrugated panels held together mechanically. Emerging mostly in industrial building uses, has been experimented with as the basis of housing on the premise that plastic is actually more evironmentally sound than it has long been given credit for based on its use of recycled cellulose and the low energy overhead of its production compared to alloys and concrete. Currently no open source or public domain systems exist nor are there any truly standard systems independent of any one manufacturer, though there may be no obstacles to the creation of these. Little explored because of its newness, FRP has has much potential as a maker technology owing to the relatively small scale and low energy of pultrusion systems compared to alloy extrusion and the potential to develop epoxies that are low-toxic and plant sourced.

Modular Stressed Skin Systems - Stressed skin systems are typified by the semi-monocoque structures common to early aircraft and boats as well as 'woven panel domes' where a kind of geodesic dome is made by layered panels and tension structures where a tent-like membrane is tensioned by a system of frames or piers. Stressed skin systems are generally based on the combination of a 'skin' or 'hull' structure that is tensioned by either its own material stiffness or by a frame structure so as to translate localized compression forces into distributed tension forces. In effect. working in the manner of a 'closed web' or 'box' truss or a 'tensegrity' structure employing a skin rather than tension cables. Though a common structural technique, very few attempts have been made to modularize these systems on anything but a self-contained macrostructural element level -in effect using these kinds of structures as a whole unit element of a much larger structure. The International Space Station is a good example of this approach. However, in a few instances attempts at modularizing the component elements of a stressed skin structure have been explored, most commonly in the form of contemporary tents and tension structures and in the use of plywood or SIP (structural insulated panel) shell structures. Plywood domes (, hypoid or conics roof systems (, and systems like Vinay Gupta's Hexayurt ( may be some of the best current examples of this. In the 1960s designer Ken Isaacs experimented with stressed skin plywood cabin or 'microhouse' designs that employed standardized modular panel and spar elements connected by small block joints or alloy angles, the edge seams sealed with aluminum tape. Some of the more LEM-spacecraft-like designs Isaacs employed have been revived recently with new geometry in work by N55 ( Conventional wood frame systems for housing have evolved into a kind of stressed skin system based on the reliance on external cladding (and to a lesser extent internal cladding) for structural integrity. These, however, have only recently begun being used in any modular way on the level of panel module systems using factory produced panels or OSB based SIPs. No standardized systems have developed for this in the conventional housing industry in the western world, but one potential standardized system does exist, however, in the form of the Volkshaus system developed in Japan by the design group Landship ( and marketed commercially by several companies. ( An evolution in some ways of the traditional Japanese 'ken' system, Volkshaus uses steel plate joined post and beam framing with prefabricated stressed skin composite wall, floor, and roofing panels. In spite of its heritage, the resulting sophisticated homes have more in common with Scandinavian contemporary housing in their appearance. The system is potentially feasible in both a DIY and factory setting, though currently its use is dominated by several companies in Japan. Its developers have produced books and even design software for builders, but only in Japanese.

T-Slot Aluminum Profile Framing - The premier modular building system today, is based on the use of extruded aluminum alloy profiles that feature integral T-shaped channels to which bolt connectors are attached to link them into simple post and beam frame structures to which can be attached an endless assortment of modular fittings and equipment. Fittings allow for surface-mount attachment as well as integral of attachment based on fitting mounted inside the ends of profiles. Profiles also often feature multiple hollow interior channels both for reinforcement and to serve as the basis pneumatic and hydraulic power distribution or can serve as cable runs. Truss systems have also been made with these, based on open and closed web trusses assembled as composites of several profiles and connecting parts. In a few cases space frames have been produced. Appearing sometime in the 20th century, T-Slot was introduced in the late 1960s or early 1970s for the construction of custom industrial automation systems, offering a powerful solution for the high cost for the development and adaptation of automated systems. It quickly became ubiquitous for laboratory equipment and prototype robotics and eventually supplanted Box Beam as the most popular building system among eco-technology experimenters. With very high strength to weight performance and a growing variety of profile shapes, new alternative materials such as carbon fiber, FRP, and wood, and a huge worldwide catalog of accessory parts, today its list of uses are endless and with the recent introduction of large scale profiles it has begun being used for housing and plug-in architecture systems based on post and beam structures. With most new digital machine tools commonly being prototyped using T-Slot, the variety of sources very numerous, and the variety of the off-the-shelf parts very high, T-Slot represents one of the best choices for maker projects. However, it remains somewhat costly due to manufacturer pricing focused on a typically spendthrift technical/industrial business market. Curiously, as ubiquitous as it is, T-Slot remains little known at the DIY enthusiast level, largely due to a lack of any media about its use. Similarly, most manufacturers of T-Slot products are so culturally focused on the industrial market they are largely oblivious to the huge variety of other uses their own products have actually been put to.

MK Profiles - Bosch Profiles - 80:20 - Tslots - Jeriko House - iT House - Tomahouses -

More Information

  1. Non-Modular Building Systems
  2. Open Source Manufacturing Tools