Mechanical fixing secures components into a suitable substrate with physical fasteners. For roof coverings, the fixing arrangement belongs to a specified system.
What does this mean on your roof?
The term does not specify fastener type, substrate or distribution. Those choices relate to the roof, materials and forces that need to be transferred.
Adding an arbitrary screw is therefore not a reasoned fastening design for an existing roof or evidence that the surrounding attachment arrangement is adequate.
When comparing proposals, ask which substrate has been assumed and how unknown or damaged sections will be investigated. Access to that substrate can affect work sequence and retained layers. Record changes made during execution. This leaves a useful record of whether the completed assembly corresponds to the system underlying the original proposal and material selection, particularly where concealed construction differs from expectations.
Frequently asked questions
Is every roof board a suitable substrate?
The name alone does not establish suitability. Material, condition and system need assessment.
Is mechanical fixing better than bonding?
There is no universally best method. Suitability depends on the complete roof system.
Consulted 19 September 2026. Check requirements for your own address and selected system.