Fibre cement on a factory roof: what the production process demands

A label such as “light manufacturing” gives little design information. Two factories of equal size can expose the roof to very different conditions. Include foreseeable changes in the process. Introducing frequent washdowns in a plant designed for dry production can require the envelope and its junctions to be reassessed.

Provide extraction for steam released by the process. Fibre cement has limited moisture-buffering capacity and its underside can still become wet. In a heated hall, both insulation and airtightness matter. A leaking duct penetration can carry moist air into cold layers. Coordinate the roof design with the ventilation design so that vapour movement is addressed throughout the assembly.

Give the system supplier and envelope designer the names of the substances, how they reach the roof and the humidity during exposure. Fibre cement does not rust like sheet steel, but its chemical resistance and that of its coating depend on the substance. Check fasteners, metal supports, flashings and seals individually. Resistance data for a sheet apply only to the component tested.

Check the detergent, water temperature and application method against the sheet manufacturer’s instructions. A process suitable for machinery can damage the roof surface or joints. Verify any proposed pressure jet or cleaning agent, trace where the water drains and check whether it collects in laps. Where hygiene rules prescribe a cleaning method, design the whole roof assembly with that method in mind.

Support ducts, fans and rooftop units from the building structure. Fragile sheets provide weather protection around properly detailed penetrations. Allow for vibration, thermal movement and servicing. Plan safe access to equipment that requires inspection without walking directly on the covering. Assign responsibility for the equipment, its supports and the roof seal in the specification.

The sheet’s reaction to fire is one material property. To determine the fire resistance of the roof, assess its structure, insulation and connections as a complete assembly. Rain noise and production noise also need separate assessments. Use evidence for the complete system wherever a requirement applies to the roof or the hall as a whole.

Schedule inspections around production and access to the areas below the roof. Check joints, drainage and points where dust accumulates. Keep sheet identification and accessory records for repairs. Review the original assumptions when a new steam source or cleaning chemical is introduced. These changes can affect the roof long before any damage becomes visible.

Use the process description, moisture sources, substances and cleaning regime to confirm the suitability of the covering, fasteners, roof layers and service penetrations.