Typology Glossary
Volumetric Modular
These are volumetric modular units, which are transported to site as 3 dimensional building elements.
They could then be attached to an existing building, linked together to form complete or stand alone buildings where the only required manual elements of the project would be suitable foundations and utility services.
The internal fit-out, finishes and building services would normally be installed and commissioned in the modules in the factory. External façade claddings and roof treatments are often installed on site.
Bathroom & Kitchen Pods
Pods are fully finished and usually include all mechanical and electrical services. They could be manufactured using concrete, steel and plasterboard, fibre-glass or a combination of these.
Applications include hotels, student accommodation, hospitals, and commercial offices, in fact anywhere that there is a requirement for a multiple number of units of the same size or shape.
There are manufacturers who deliver product as flat-pack assemblies for use in refurbishment projects and although technically these are not pods they tend to put in the same category.
Foundation Systems
Pre-cast foundation beams can be linked together on site to provide foundation support for either traditional masonry build methods or offsite construction techniques.
These foundation beams can be both ground supported or use conventional piles with or without caps depending on the local ground conditions.
Other variants of pre-engineered foundation systems include pre-fabricated ground floor formwork raft systems where the perimeter edge reinforcing and details are pre-fabricated in steel and the concrete poured in-situ to complete the reinforced raft foundation on site.
Precast Concrete
Structural frame using pre-cast concrete columns, beams or load-bearing wall and floor panels, these may be grey pre-cast in colour or factory finished internally or externally and remain exposed in the final building.
The extent of onsite work varies between projects. Pre-cast concrete may be used in conjunction with in situ concrete or structural steel as part of a hybrid frame.
As early as the 1840s Pre cast concrete elements were used in the construction of some London theatres.
Panellised Wall Cladding
Usually non structural, these are made up from a wide range of components assembled in a factory to produce an external walling system.
The intention is to enclose the building as rapidly as possible to create a dry envelope and allow finishing trades to commence as early as possible.
This approach typically incorporates the secondary (usually steel) support structure, external cladding, windows, doors, insulation and in some cases the internal lining and first-fix electrics.
Building Components
Pre-assembled components forming more complete, larger elements of the building not covered by some form of the more recognised categories.
Typical examples include factory pre-assembled and tested toilet cisterns and wash hand basins fitted with taps. Pre-glazed and surface finished windows and roof trusses are perhaps good examples of Offsite that have become accepted as ""normal"" construction methods.
Careful design of components and their interfaces is crucial for effective manufacture and assembly.
Light Steel Frame
Structural panels assembled from cold-formed galvanised steel sections. Light steel framing is typically used as the primary structure in housing and other building types of up to four storeys.
For taller buildings it can be complemented by the use of hot-rolled members at key locations.
Roofing Systems
Preassembled elements of the roof can be made in the factory and delivered to site to enable rapid installation of the roof structure complete with weather membrane and insulation.
These systems tend to be bespoke and can be delivered to site where a number of delivered units can be linked together at ground level before being craned into position as single larger roof elements.
Certification & Testing
Independent approval of offsite manufactured technology involves testing and verification of the system against Building Regulations and other legislative requirements, including durability and suitability of the construction technique for the intended application.
There are common assessment guidelines known as ETAG's (European Technical Assessment Guidelines) for many offsite techniques which set common assessment criteria across Europe. Similarly with testing of offsite techniques which should wherever possible be tested by UKAS accredited test authorities.
Timber Frame
Probably the most recognisable Offsite principle, consisting of structural panels made up of timber studs, stiffened on one side with oriented strand or similar board, which form the inner leaf of the cavity wall.
They are brought to site and fixed together to form a rigid load-bearing superstructure.
Pre-assembled Services
Mechanical and electrical services are ideally suited to the factory as they typically involve significant labour skills and are complex in nature.
They could be packaged or skid-mounted preassembled plant rooms pre-finished in the factory for mains connection on site, but they might just as easily be integrated ductwork with pipe-work and cables in a support tray mounted in the ceiling or under the floor.
This principle makes it possible to test and part commission elements in the factory prior to delivery on site.
Specialist Consultants
The offsite construction industry relies on specialist consultants to advise clients, developers and project teams on how best to use this relatively new construction technology.
This advice should be independent and based on a wide knowledge of the offsite systems available and how these offsite techniques should best be integrated and embedded into the on site build elements of construction.
Offsite consultants may specialise in just one offsite technique while others may engage teams with individual specialists to cover the entire range of offsite technologies available.
Structural Insulated Panel
Or SIPS are Structural sandwich panels typically comprising a core of insulation (foam for example) with plywood, strand-board or cement-bonded particleboard skins, bonded together to form one structural, load-bearing panel.
Technically, they are similar to timber frame components and are ideal for use ""in room in the roof"" situations. Properly used, the system needs no frame or skeleton to support it.
Permanent Formwork
ICF or insulated concrete formwork is a building system made from interlocking hollow insulating blocks used to create the wall superstructure of generally low rise buildings.
The insulating material is typically expanded polystyrene and the systems, include interlocking plastic components restraining both outer faces of the blocks to resist the hydrostatic pressure.
Steel reinforcing is introduced into the void before pouring the mix on site to create a reinforced and fully insulated load bearing superstructure.
Other forms of permanent formwork include twin-wall which like ICF is recognised as a proprietary building system.
Installation Services
These are specialised teams offering nationwide installation services for offsite techniques, particularly where the offsite manufacturer does not provide an installation service themselves.
These installation teams would be trained and ideally accredited for the offsite typology being installed. Many reputable offsite manufacturers provide an approved installer network or training to ensure that installation is undertaken safely and expertly.
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