The following post includes excerpts from our book Understanding Architectural Details – Commercial.
Introduction to Cladding Details
Cladding Details – Functional Requirements
There are a wide variety of walling and cladding systems available for commercial and industrial structures, with many factors determining what construction method is chosen. The walls of any high rise or commercial structures must fulfil a set of performance criteria, and the cladding and walling options of today meet those standards. These functional requirements include:
Strength and stability
The cladding system should be able to support its own weight between fixings or framing members. It should also have sufficient strength to resist wind forces, and allow for differential movement between the wall system and the structural frame.
Protection from weather and moisture
The walling system must resist rain penetration, and wind penetration.
A building must achieve certain thermal comfort standards, and the cladding system will have an impact
on these standards. It is important that the building provides adequate thermal insulation, but also avoids excessive solar heat gain. When working with structural frames, another key design factor is the avoidance of thermal bridging.
The walling system must resist sound transmission, both impact sound and airborne sound.
Resistance to fire
Cladding and its resistance to fire goes beyond the scope of this post. However, it is important that any cladding materials resist the spread of fire, and the selection of materials must comply with all appropriate regulations and standards.
Other considerations with cladding systems is the spread of fire across surface materials, and within concealed spaces such as cavities and voids in construction. Cavity barriers and cavity stops must be specified as a barrier where applicable to prevent the spread of smoke and flames.
The regulations state that cavity barriers must be provided to close the edges of cavities, including around openings, and any junction between an external or internal cavity wall and every compartment floor and compartment wall. They must also be provided to sub divide any cavity, including any roof space so that the distance between cavity barriers does not exceed dimensions given in the regulations.
There are a wide variety of cavity barriers, stops and closers on the market to fulfil the requirements of the building regulations. The requirements for resistance to fire in high rise and commercial applications is intricate and requires thoughtful design. For advice on fire protection, seek guidance from the Approved Documents, specifically Part B, and a certified fire consultant.
With walling and cladding systems often being completely sealed units, it is more common to incorporate mechanical ventilation systems to provide a regular change of air required for human comfort. Open plan spaces and the use of atriums often assist with the movement of air, along with stack ventilation designs.
A wall finish of brick or masonry will require little lifetime maintenance, whereas a finish of glass requires regular cleaning. The selection of a walling system will need to consider the maintenance requirements and costs, along with the safety precautions required for said maintenance.
The structural frame allows for the possibility of numerous variations in the form and appearance of buildings, with a vast variety of materials and finishes constantly changing and progressing. Wall and cladding systems can be categorised in a number of ways. For this book, I have narrowed down the systems into five main areas:
- Solid wall systems
- Cladding façades and cladding panels
- Rain screen panels
- Glazed curtain walling
- Infill walling
For this post, we will consider cladding facades and cladding panels.
Cladding Facades and Cladding Panels
This is quite a wide category, covering anything from a facing applied to a solid backing wall, to composite panels.
Cladding to a building can be described as components that are attached to the primary structure of a building to form a non load bearing external surface. A cladding will fulfil many duties, above just creating a weather protective barrier to the building.
A cladding system will be selected based on a number of requirements, such as:
- The building’s end use
- The required internal and external conditions
- The necessary durability of the system and maintenance requirements
- Planning requirements and the local context of the building
- Building regulation requirements
Cladding systems can be formed using many materials including:
- various metals
- amongst others
In this cladding details post, we will focus on concrete cladding panel details.
Concrete cladding panels
Precast concrete cladding panels offer a variation of finishes and sizes, being factory made to suit the designers needs. Sometimes incorporating an insulation layer, the precast units can be self supporting, and stacked together or interlocked up to about 10m with lateral support provided by the structural frame. Concrete cladding is also available as a rainscreen option (which we will look at later) and fixed to a backing wall using fixing brackets or onto a stainless steel frame.
Panels can span large distances, i.e. storey to storey, or indeed be much smaller panels. Selection of the panel type would take into account some of the following:
- Structural frame spacing, determining the span of the panels
- Weight of panels required
- Method of jointing panels
- Finish or facing requirements
- Weather conditions and exposure of the building and site
Concrete Cladding Details Examples
The following images provide concrete cladding details.
Concrete Cladding Details – Wall Section
Concrete cladding details – wall section 3D
Concrete cladding foundation detail
Concrete cladding foundation detail 3D
Concrete cladding details – Window head detail
Concrete cladding details – Window head detail 3D
Concrete cladding details – window sill detail
Concrete cladding details – window sill detail 3D
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