Understand the existing roof
Construction, condition, drainage, loading and interfaces affect what may be suitable. An overlay should not be assumed suitable without assessment.
Compare the specification
Ask how the proposed system addresses waterproofing, thermal requirements, fire performance, detailing and maintenance. Specialist design input may be needed.
Read the warranty terms
Clarify who provides any warranty, what is covered, exclusions and inspection or maintenance obligations. Do not assume every installation has the same cover.
This guide is general information. Site-specific decisions require an appropriate assessment and specification.
Questions about planning the work
Which commercial roofing system is best?
There is no single system that suits every building. Existing construction, condition, drainage, loading, use and the required performance all affect suitability. Compare systems against an agreed specification rather than selecting on material name alone.
What should be checked before an overlay is specified?
Assess the condition and compatibility of the existing construction, moisture, substrate, loading and junctions. The proposed system needs appropriate design and detailing; retaining the existing roof should not be assumed suitable.
What should I ask about a roofing warranty?
Ask who issues it, which work and materials are covered, the duration and exclusions, and what inspections or maintenance are required. Confirm the applicable terms in writing for the proposed specification.