Prefabrication experiments - 116 - Structures - 7 - Planar construction from monolithic panels to structural insulated panels

A load bearing organization of vertical and horizontal thick flat surfaces is the simplest form of planar construction. Prefabricated panels can be manufactured in any material from lightweight steel or wood to more heavyweight reinforced concrete. Panels can be dry fastened and bolted to transfer vertical and horizontal stresses through the panels' thickness.  Architectural concrete panels, steel stressed skin panels or the contemporary cross-laminated timber panels are the most common manufactured elements used in this type of moderately spanning structures. Habitually flat packed, panels are easily transported and produce an easy to assemble construction kit, where floor panels span from one wall panel to another.

Whether timber, steel or concrete, exposed joinery connects overlaid panel edges in simple "T" or "L" patterns. Once the bearing walls are anchored to a foundation, the floors and walls are continuously stacked in a platform arrangement to reach varying heights. If simplicity is a major advantage, planning flexibility is one of the drawbacks, as the vertical planes impede free flowing open plans. The 9 m x 6 m prism like spans offer less overall building adaptability as compared to open skeletal frame structures.

Concrete and mass timber panels have the additional drawback of weight and make sense for large multi-story buildings. For smaller scale structures, commercial or residential, structural insulated panels (SIPs) are a variant of this type of planar construction, with a much lighter panel.  A SIP is a type of stressed skin lightweight panel composed of en external sheathing of plywood or other material with a high density polyurethane foam core. This type of structural panel can be manufactured to varying thicknesses and manufactured with windows, doors or wiring networks being milled by numerically controlled cutters in the factory. 

Architects Ian Hsu and Gabriel Rudolphy explored SIPs in their recent project for the Casa SIP m3 prototype. The casa SIP showcases the modular panels as walls, floors and roofs and reproduces a simple type of cardboard model like building system using rectangular flat surfaces. The casa SIP project employs this simple construction method to produce dynamic volumes and spaces as well as a clear tectonic expression planar construction.

Mass timber planar construction (left) Casa SIP by Ian Hsu and Gabriel Rudolphy (right)