The evolution of architecture involves not only improvements in construction, insulation, building methods or aesthetics, but equally in materials and especially in the range of material types we can choose from. This influences our options and therefore our architecture. The weight of a material may seem at first glance not a very important factor in a building. A building after all stands still, there is no need to move it, it does not transport anything, so the endeavors of the automotive and aerospace industries to find the lightest possible materials to save on fuel are not needed when designing a building. Heaviness is even a requirement, mass provides effective heat accumulation, good acoustics and, like in the tale of the big bad wolf and the three pigs, a solid brick house does have its advantages when you are threatened by a hurricane.

A building however needs foundations, moreover all components must be transported and assembled, and at some future time demolished again, at which time there are recycling issues to consider. Poor heat accumulation in lightweight material can be countered with smart materials capable of storing heat in the form of latent energy to be released as heat as required when cooling down.

So lightweight material is relevant for economic, ARBO (working conditions) and environmental protection reasons, whether it is used for structural foundation reasons, construction physical reasons like insulation, acoustics or weatherproof finishes, or for aesthetic reasons like finishes on floors, facades, walls and ceilings. Subject to applicable requirements, the material must be of a specific strength, pressure and tensile absorption degree, durable/sustainable, scratch-proof, UV resistant, manageable or glossy. All added reasons, when choosing materials, to prepare a Program of Requirements and not randomly pick something from the shelf just because that is what we know. The weight of a material is expressed in density – kilos per cubic meter – but that is not all. Its form makes for higher efficiency, i.e. assembling the package. Foamed, laminated, honeycomb shaped, woven, knitted; technologies to trap air inside the package; air, the lightest material of all.

So, we inflate. Tent constructions made of EFTE, inflated to make strong ultra-light constructions. Texlon film is an EFTE film that is durable, strong and light, and used specifically in inflatable constructions like skylights and roof domes as well as in inflatable facades.

Foamed materials like aluminum foam a material made by heating and pressurizing aluminum powder with a foam component into a mould and creating a type of “Brittle Candy” aluminum. Alusion and Alcarbon now try to appeal to the architectural market with this material, originally developed for high grade industries.

Composites made of lightweight elements bonded together with a binder/glue, like Geofill. This is a foam-glass grain consisting for 80% of waste material generated by the bottle making industry, neon tubes, light bulbs, float glass and glass fiber and window shields. From these grains are made foam-glass pearls which are added to concrete. It is heat insulating and acoustic, lightweight and readily recyclable.

Mikor is a honeycombed foam that is both strong and lightweight.

Moniflex is made of cellulose. It consists of transparent layers making it great insulation material, and it is used to address moisture resistance, absorption of vibrations, and lightweight issues.

Featherpanel is made of concrete but weighs only 25% compared to regular concrete. Available in many colors and textures. Being lightweight it is easily bonded and can be processed using regular tools.

Ideal obviously is a construction where materials are used only on the spots where forces need to be absorbed. The architecture of Calatrava, based on the construction of skeleton structure, is a good example of this principle. Rapid prototyping can make from 1 material, either artificial or starch, any desired shape. This enables the construction of gossamer fine, filigree like structures.

Rapid prototyping technology may be compared to 3D printing technology whereby 3D objects are printed via a laser. The SLA technology Stereolithography creates an object by superimposing layer on layer while the object is submerged in a bath of liquid polymers and then laser hardened. The epoxy used for this technology looks like a hard, virtually transparent material to which can be added all kinds of color pigments. The SLS (Selective Laser Sintering) technology follows the same principle but using a liquid a powdery substance instead. The resultant objects have a milky white powdery appearance.

Glass fiber remains a popular lightweight support structure. Hunter Douglas recently used its renowned blind-making technology in a material to be used in super-light yet strong ceiling boards. Tensile strength allows big sizes and large spans. So lightweight materials are mainly a matter of trapping air and using super-strong materials using only a little of the latter; provided they are used intelligently.