Information on the types of cladding and the issues they can raise.
The move towards sustainable, thermally-insulated buildings, combined with modern building methods has seen a significant increase in the use of cladding systems on buildings within the last 25 years.
Following the tragic event at Grenfell Tower in June 2017, many organisations, businesses and property owners are concerned about the potential presence of combustible cladding and insulation materials in their buildings. You may have concerns that your own premises feature such materials.
The three most common methods or systems used are rainscreen cladding, external thermally insulated composite systems (ETICS) and insulated composite/sandwich panels.
This type of cladding was used on Grenfell Tower and is commonly used to improve the aesthetics and thermal efficiency of older buildings. It is a built-up system consisting of insulation material that can be directly bonded or fixed to a solid wall, or a lining board on a steel-framed building. External cladding panels are then fitted on a lightweight steel frame leaving a small air gap of 50mm between the panels and insulation to prevent condensation build-up.
As with rain screen cladding this is a built up system where insulation material is directly attached to a solid wall of a building or a lining board. However here, the insulation layer tends to be thicker and is directly covered with a cement render to provide weather protection. This type of cladding system is more commonly used on new builds.
Typically used to form the walls and/or roof of steel portal framed buildings, the panels consist of a central core of insulation material sandwiched between powder-coated painted steel or aluminium sheets
The main issue with all 3 systems is whether the insulation material used is combustible or not. In addition, with rainscreen cladding the inclusion of the air gap provides a ready source of oxygen so if combined with combustible insulation and a combustible cored outer panel it can cause a flue effect increasing the intensity and channelling any fire upwards, as happened with Grenfell.
A number of both combustible and non-combustible materials can be used as the insulation/core material. The most common combustible materials used are:
- expanded polystyrene (EPS)
- extruded polystyrene (XPS)
- polyurethane (PUR)
- polyisocyanurate (PIR).
Non-combustible materials include:
- mineral wool (glass fibre)
- mineral wool (rock fibre)
- cellular glass.
All of which are more expensive than foam cored panels.
Identifying the exact make and core of the cladding can be difficult once the building has been constructed. Many cladding systems look similar, and most of the major manufacturers produce various versions of the same cladding system/panel using differing core materials.
Some PUR and PIR cored systems even have Loss Prevention Council approval under testing standards LPS1181 & LPS1208 and are commonly referred to as Fire Safe.
There are a number of ways to identify the exact product used and whether there is any combustible content in the cladding panel or insulation material. For buildings constructed or clad within the last 10-15 years, information should be to hand, from:
- The architect
- The tender document for the project
- The operation and maintenance manual for the building.
If no information can be found, as a last resort it may be possible to remove a panel (or section) to enable identification by a qualified person. This should only be done by a competent contractor and where panels (or sections) are removed, they must be re-fitted correctly and the core capped as required by the manufacturer's guidelines.
Once you have identified the materials used in your cladding system we would suggest the following measures be taken:
- Review your existing Fire Risk Assessment and fire safety measures in your building to determine whether any additional fire safety measures are necessary. E.g. hot work permits, additional fire detection, sprinkler systems, secondary escape routes.
- Review your emergency evacuation procedures for the premises making sure all occupants, residents and visitors are aware of the fire escape routes within the building and know what to do in the event of an emergency.
- Introduce an appropriate inspection and maintenance regime of your cladding system. The inspection regime should check the general condition of cladding and include inspection of the face of the cladding system for damage and exposure of the panel core. Where damage is noted repairs should be made promptly.
- Contact your insurer and provide details of the make, model and insulation materials used.