Roof Coating Installation Audits Explained: What They Can and Cannot Tell You
Installation audits are a common feature of many industrial roof coating projects. Most roof coating manufacturers undertake site visits during the course of a project to assess progress, review workmanship and confirm that their materials are being used in accordance with the specification.
Despite this, installation audits are often misunderstood.
It is not uncommon for building owners, surveyors or contractors to assume that a manufacturer’s audit constitutes a full inspection of the works or a form of project sign-off. In reality, an installation audit is a snapshot in time, carried out within practical limitations and for a specific purpose.
Understanding what an installation audit can and cannot tell you is important when assessing project quality, allocating responsibility and understanding the role of the manufacturer during the installation process.
What Is A Roof Coating Installation Audit?
A roof coating installation audit is a site visit undertaken by a manufacturer’s representative during the course of the works.
The purpose of the visit is typically to assess whether the coating system is being installed broadly in accordance with the manufacturer’s recommendations and project specification.
During an audit, observations may include:
- Surface preparation standards.
- Treatment of corrosion defects.
- Application methods.
- Material usage.
- General workmanship.
- Project progress.
- Areas requiring remedial attention.
At Liquasil, installation audits are recorded using a dedicated surveying system, allowing observations, photographs and recommendations to be documented in a structured format.
The purpose of an audit is to assist the contractor and provide confidence that the specified system is being applied correctly. It is not intended to replace the contractor’s own quality control procedures.
What An Installation Audit Is Not
One of the most common misconceptions is that an installation audit represents a full inspection of the completed works.
It does not.
An installation audit is not:
- Continuous supervision of the works.
- A Clerk of Works service.
- Independent quality assurance.
- A project management service.
- Certification that every area has been inspected.
- A guarantee that defects do not exist elsewhere on the roof.
- A roof survey
The manufacturer’s role is fundamentally different from that of the contractor, project manager or independent inspector.
The contractor remains responsible for the quality of the installation and compliance with the project specification.
Why Every Area Cannot Be Inspected
Industrial roofs are often extensive, complex and occupied environments.
Even where access is available, it is rarely practical to inspect every square metre of a roof during a single visit.
There may be limitations caused by:
- Roof size.
- Ongoing works.
- Restricted access.
- Safety considerations.
- Weather conditions.
- Areas that cannot be reached without disrupting operations.
- Wet coatings that cannot be walked upon.
For this reason, installation audits are generally based upon representative observations made at the time of the visit.
This approach is common throughout the construction industry and reflects the practical realities of working on large industrial buildings.
Why Defects May Still Be Identified After An Audit
Occasionally, questions arise when a defect is discovered after an audit has taken place.
Common examples include:
- Areas completed after the audit visit.
- Localised workmanship issues outside inspected areas.
- Damage caused by subsequent trades.
- Defects concealed at the time of inspection.
- Areas that were inaccessible during the visit.
- Weather-related issues occurring after the inspection.
- Variations in coating thickness across large roof areas.
The existence of a later defect does not necessarily mean that the defect was visible, accessible or present when the audit was undertaken.
An installation audit records observations made at the time of inspection and should be viewed within that context.
Representative Sampling
Most professional inspections rely upon representative sampling rather than examination of every square metre.
Building surveys, coating inspections, corrosion surveys and many other technical inspections involve drawing conclusions from representative observations made at accessible locations.
During an audit, an inspector may check coating thickness at a number of representative locations across a 10,000m² roof.
Those readings provide confidence that the coating is being applied correctly but do not constitute measurement of every square metre of the completed installation.
Can Manufacturers Check Every Coating Thickness?
Film thickness is an important aspect of many roof coating specifications.
However, it is rarely practical to take measurements across every square metre of a completed roof.
Spot checks may be undertaken where appropriate, but these provide information about specific locations only.
As with any inspection process, conclusions are based upon representative observations rather than exhaustive testing of every area.
Where coating thickness forms a critical project requirement, this should be considered alongside the contractor’s own quality assurance procedures and material usage records.
Dry Film Thickness Measurement
Dry film thickness measurements are typically taken using an Elcometer 456 coating thickness gauge, a non-destructive instrument designed to measure coating thickness on metal substrates. The gauge is capable of taking rapid, repeatable measurements and can store multiple readings for analysis and reporting.
Silicone roof coatings present a particular challenge when measuring film thickness because the coating surface remains relatively soft and flexible compared with conventional paints and coatings. For this reason, Liquasil uses a specialist soft-contact probe designed to minimise compression of the coating during measurement. This helps improve the accuracy and repeatability of dry film thickness readings, particularly on thicker silicone coating systems.
As with any inspection process, measurements are taken at representative locations across the roof rather than every square metre of the completed installation.
Wet Film Thickness Measurement
Wet film thickness is typically checked during application using a wet film thickness comb, such as the Elcometer 154. The comb incorporates a series of calibrated teeth of known heights and is pressed vertically into the freshly applied coating until it contacts the substrate. When the comb is removed, some teeth will be wetted by the coating while others remain dry. The wet film thickness is determined by identifying the highest wetted tooth and the next dry tooth, indicating that the coating thickness lies between these two values.
For example, where a coating specification requires a minimum wet film thickness of 400 microns, the applicator can periodically check the coating during application to confirm that sufficient material is being applied. As shown in the photographs, the comb is inserted directly into the wet silicone coating and immediately removed to provide an indication of the coating thickness at that location.
Wet film thickness combs provide a rapid and practical means of quality control during application. However, as with all inspection techniques, measurements are taken at representative locations across the roof rather than every square metre of the completed installation.
Wet film thickness measurements are generally more useful during application than dry film thickness measurements, as they allow corrective action to be taken immediately while the coating is still being applied.
Understanding Responsibilities
Successful roof refurbishment projects depend upon all parties understanding their respective responsibilities.
The Contractor
The contractor is responsible for carrying out the works in accordance with the specification, manufacturer’s recommendations and accepted industry standards.
The Manufacturer
The manufacturer is responsible for supplying materials that perform as intended and for reporting observations made during any audit visits.
The Specifier
The specifier is responsible for defining the project requirements and ensuring that the proposed solution is appropriate for the condition of the roof.
The Building Owner
The building owner remains responsible for ongoing maintenance, inspections and the reporting of defects should they arise after completion.
Installation Audits And Warranties
An installation audit should not be confused with a warranty.
A warranty defines the extent of cover being provided and the circumstances under which a claim may be considered.
An installation audit is simply one element of the quality control process undertaken during the project.
Understanding the distinction between audits, workmanship responsibilities and warranty coverage can help avoid misunderstandings should issues arise in the future.
Conclusion
Roof coating installation audits provide valuable oversight during a refurbishment project, helping to identify potential issues and promote compliance with the specification.
However, they should be viewed for what they are: professional observations made at a particular point in time, within the practical limitations of access, safety and project constraints.
An installation audit is not a substitute for contractor quality control, independent inspection or continuous supervision of the works.
Understanding these limitations allows building owners, surveyors and contractors to make informed decisions and maintain realistic expectations regarding the role of the manufacturer during a roof coating project.
Frequently Asked Questions
Does a manufacturer audit mean the roof has been signed off?
A manufacturer’s audit is to ensure that the conditions for a successful installation are being met and that installation instructions are being followed. However, a manufacturer cannot sign off projects.
Who is responsible if a defect is found after an audit?
Most projects are conducted under a formal JCT or other construction industry contract that usually contain a defects liability period of 6-12 months, during which time the installer is responsible for rectification of any defects.
Are installation audits required for a warranty?
Not always. Some smaller or directly instructed projects might not require a manufacturer’s audit, in which case a self-certified warranty might be issued. Audits are typically necessary for larger, specified projects. This should be stated in the project specification.
What is the difference between an audit and a Clerk of Works inspection?
A Clerk of Works inspection is carried out by a professional, whose role is to ensure that all standards are properly maintained throughout a project. A manufacturer is not typically qualified in this role and can only comment on their own product installation.