Glossary · Two-word term
Entire System
In short
all interconnected components forming a complete cladding assembly and wall build-up
The term "entire system" refers to the comprehensive assembly of all materials and components forming a building's external wall build-up. It encompasses everything from the outer cladding panels and subframes to insulation and internal substrates, viewed as a single functional unit.
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Entire System
Definition and Technical Scope
In the context of the UK built environment, the term "entire system" refers to the holistic assembly of all interconnected components that constitute a complete cladding installation and the associated external wall build-up. This definition extends beyond the visible aesthetic rainscreen to include every layer between the internal face of the structural wall and the external environment.
An entire system typically comprises the outer leaf (cladding panels or masonry), the supporting subframe or rail system, fixings, cavity barriers, insulation, breather membranes, and the inner substrate. In technical assessments, the term ensures that no single component is viewed in isolation. The performance of a wall—whether regarding thermal efficiency, moisture management, or structural integrity—is a product of how these disparate materials interact under operational conditions.
Regulatory Context in England and Wales
The regulatory framework in England and Wales, particularly following the introduction of the Building Safety Act 2022 and updates to the Building Regulations 2010, emphasizes the performance of the external wall as a whole. Approved Document B (Fire Safety) and the functional requirements of the Building Regulations necessitate that the entire system achieves specific performance standards, depending on the building's height and use.
For buildings over a certain height threshold, the "entire system" approach is fundamental to demonstrating compliance with Requirement B4. This requires that the external walls of the building shall adequately resist the spread of fire over the walls and from one building to another. Professional assessments, such as those conducted under the EWS1 (External Wall System) process, are designed to evaluate the entire system rather than making assumptions based on the external finish alone.
Role in Testing and Certification
When cladding systems undergo testing, such as large-scale fire testing to BS 8414, the "entire system" is the subject of the evaluation. These tests do not merely grade a single panel; they assess the performance of the full build-up, including the specific configuration of rails, the type of insulation, and the exact placement of cavity barriers. A change to a single component—such as substituting one brand of insulation for another, even if it carries the same nominal fire rating—technically results in a different "entire system" that may not be covered by the original test data.
This distinction is critical during remediation or replacement works. If a building is being stripped of its original cladding, the replacement must be designed as a coordinated entire system. Architects and fire engineers must ensure that the new combination of materials has been tested or assessed as a unified assembly to meet the prevailing building standards.
Relationship to Building Fabric
The entire system is an integral part of the building fabric, serving as the primary barrier against the elements. Its function is multi-faceted:
- Structural Support: The subframe must be compatible with both the cladding panels and the building’s primary structure to manage dead loads and wind loading.
- Thermal Performance: The insulation layer and the management of thermal bridging across the subframe determine the U-value of the wall.
- Moisture Management: The system must allow for drainage and ventilation through the cavity while preventing water ingress into the internal structure.
- Fire Performance: Cavity barriers must be correctly specified and installed to close the void behind the cladding in the event of a fire, maintaining the integrity of the system.
A failure in any one of these areas is often a failure of the entire system's design or execution, rather than a failure of an individual material.
Entire System
Components of a Typical Entire System
The following table outlines the primary layers typically found within a modern rainscreen cladding system in the UK.
| Layer | Typical Components | Function |
|---|---|---|
| External Finish | ACM, HPL, Zinc, Terracotta, or Stone | Weather protection and aesthetics |
| Cavity | Open air space | Ventilation and drainage of moisture |
| Substructure | Aluminium rails, brackets, and fixings | Transferring loads to the building frame |
| Fire Stop | Intumescent or mineral wool cavity barriers | Restricting fire spread within the cavity |
| Insulation | Mineral wool, PIR, or phenolic foam | Thermal regulation |
| Substrate | SFS, masonry, or timber frame | The structural base for the cladding |
Guidance for Building Owners and Managers
For those responsible for the management of multi-storey residential or commercial buildings, such as Resident Management Company (RMC) directors or managing agents, understanding the "entire system" is vital during the procurement of Fire Risk Appraisals of External Walls (FRAEW). It is insufficient to provide a surveyor with the specification of the external panels alone.
Comprehensive records, including "as-built" drawings, operation and maintenance (O&M) manuals, and site inspection records, are required to confirm the composition of the entire system. Where records are incomplete, invasive inspections are often necessary to identify hidden components like the type of insulation or the presence of cavity barriers. Decisions regarding remediation are based on the risk profile of the entire system; a panel that might be considered high-risk in one assembly might be managed differently if the rest of the system includes robust mitigation measures.
Common Misunderstandings
A frequent misunderstanding is the belief that a "non-combustible" outer panel automatically renders the entire system compliant or low-risk. If the underlying insulation is combustible or if cavity barriers are missing, the system as a whole may not meet the functional requirements of the Building Regulations.
Another misconception involves the substitution of parts. In the automotive industry, an aftermarket part might be functionally identical to the original; in cladding, however, the "entire system" logic means that even minor deviations from the tested specification can invalidate the system's certification. Professional oversight is required whenever a component within the build-up is altered to ensure the system’s performance is not compromised.
Related Terminology
Understanding the "entire system" involves familiarity with several closely related terms:
- External Wall System (EWS): Often used interchangeably with entire system, though EWS is frequently used specifically in the context of the EWS1 valuation process.
- Build-up: A common industry term describing the sequential layers of materials from the inside out.
- Through-wall construction: Generally refers to the entire assembly from the internal plasterboard to the external cladding, often encompassing the structural studwork.
- BS 8414: The British Standard test method for determining the fire performance characteristics of non-loadbearing external cladding systems.
- Desktop Study: A professional assessment (now strictly regulated) that uses existing test data to infer the performance of an entire system that differs slightly from a previously tested configuration.
Entire System