Green walls (also referred to as living walls or vertical gardens) have become increasingly common within our urban landscape. Typically incorporated into the vertical structures of buildings, they are promoted to boost biodiversity, reduce air pollution, and help promote wellbeing.
Green walls can also influence the property risk considerations of the associated building or structure, particularly the potential for fire, water, and wind damage. When considering the design, installation, and management of green walls, engage with your broker and involve insurers early to help ensure any property risks are understood, managed, and that any underwriter concerns are addressed.
Types of green walls
Green walls can be categorised in different ways and summarised into four main types (as reported by RISCAuthority, a research scheme funded by UK insurers:
Wire trellis or net systems for climbers | Plants grow vertically via a series of wires or nets |
Troughs | Modular or stacked troughs fixed or restrained to structures with climbing, trailing or upright plants. The troughs can be manufactured from materials such as wood, plastic, or metal. |
Fabric based systems | Typically manufactured from textile fixed to structures with pockets or slits for the plant roots. |
Modular panel-based systems | Typically, rigid panels manufactured from plastic or metal and fixed to structures. The panels may also form a rainscreen element to the structure. The panels contain the growing media and are typically delivered ‘pre-grown’. |
Property risk considerations
Green walls can be installed on a range of buildings, both large and small. By definition, the walls contain combustible components and, if not properly designed and maintained, can introduce property insurance challenges, potentially increasing insurer loss estimates (influencing the potential for fire spread) and impacting risk quality. Challenges include:
Combustibility of the planted system
Combustibility of plastics or other materials within the green wall system
Management of penetrations such as windows and vents to prevent fire ingress and spread into the building and void areas
Water and wind damage potential
Potential impact to the building and surroundings if the green wall was allowed to dry out
Green walls need effective management and controls to remain a living system and avoid drying out. There have been instances where green walls have turned brown (e.g., due to irrigation failure). The risk of external fire spread is significantly increased in these circumstances with a potential impact on property insurance, building occupation, exposure to other nearby buildings and other compliance issues.
Guidance to help manage property risk.
The Fire Protection Association’s (FPA) RISCAuthority has released new guidance (opens a new window) to support all those involved with green walls, from designers to suppliers, owners to insurers. The guidance was prepared in a collaborative exercise involving UK insurers and living wall providers.
The document includes a detailed questionnaire to gather information on green walls together with detailed background information and guidance. It also includes a scoring matrix which could be used by Authorities Having Jurisdiction (AHJ) such as building control, insurers or fire authorities and can help other stakeholders understand the potential assessment approach by an AHJ.
Overall, the guidance provides a set of core principles and a methodology to gather information and assess the characteristics of green walls for property risk management and insurance purposes. The principles cover key topics, including:
appropriate fire testing
clear record keeping
fire risk assessments
system information
emergency plans
maintenance
construction materials (using non-combustible materials wherever possible)
design (including fire risk and ease of repair)
upkeep (including irrigation and management of hot work)
The process starts with Principle 1: ‘Engage with all stakeholders at the earliest opportunity and maintain dialogue for the entire lifecycle of the building’.
For further information, please visit the Lockton Risk Control page (opens a new window).
