Commercial Roofing Warranties Explained: What Building Owners Need to Know

When a commercial roof is refurbished or replaced, the warranty can be an important part of the overall roofing package.

However, not all roofing warranties provide the same type of cover.

A manufacturer warranty, product warranty and contractor workmanship guarantee can each relate to different parts of a roofing project. The terms, duration and requirements can also vary considerably between roofing systems and manufacturers.

For building owners, managing agents, housing providers and public-sector organisations, understanding what a proposed roofing warranty actually covers is therefore important when comparing specifications and quotations.

What Is a Commercial Roofing Warranty?

A roofing warranty provides defined cover relating to a roofing product, system or installation for a specified period and subject to particular terms and conditions.

Exactly what is covered depends on the type of warranty being offered.

On commercial projects, warranties may be associated with:

• Roofing materials

• Complete waterproofing systems

• Installation workmanship

• Specific components

• Manufacturer-approved specifications

The word "warranty" shouldn't therefore be treated as meaning exactly the same thing on every roofing quotation.

Clients should understand who is providing the warranty, what is covered and what conditions apply.

What Is a Manufacturer Roofing Warranty?

Many established roofing manufacturers offer warranty arrangements for commercial roofing systems installed in accordance with their requirements.

Depending on the manufacturer and system, this may involve more than simply supplying waterproofing materials.

A complete system can include components such as:

• Vapour control layers

• Insulation

• Waterproofing membranes

• Primers and adhesives

• Reinforcement

• Accessories

• Specific detailing components

The manufacturer may also provide technical input into the proposed roof specification.

The exact warranty available will depend on the manufacturer, roofing system, project and installation requirements.

Is a Product Warranty the Same as a Roofing System Warranty?

Not necessarily.

A product warranty may relate specifically to the performance or manufacture of an individual roofing product.

A system warranty can potentially relate to a wider roofing build-up installed using compatible components from the same manufacturer.

This distinction can be important on substantial commercial refurbishment projects.

A roof consists of more than its visible waterproofing layer, particularly where insulation, vapour control layers and other components form part of the new construction.

Clients should therefore check whether the proposed warranty relates to an individual product or the wider roofing system.

What Is a Contractor Workmanship Guarantee?

A contractor workmanship guarantee relates to the installation work carried out by the roofing contractor.

This is different from a manufacturer warranty.

For example, a manufacturer may provide cover relating to its roofing system subject to its own terms, while the contractor may separately provide a guarantee relating to the workmanship of the installation.

The exact arrangements vary between projects.

This is why simply comparing the number of years shown against two different roofing quotations doesn't necessarily provide a meaningful comparison.

The underlying cover may be different.

Why Do Roofing Manufacturers Use Approved Contractors?

Some commercial roofing manufacturers operate approved, registered or authorised contractor schemes.

The terminology varies between manufacturers, as do the requirements of each scheme.

These arrangements can help manufacturers maintain installation standards for their systems and may form part of the requirements for certain warranty options.

PRC works with a range of established commercial roofing manufacturers, including Bauder, Garland, Langley, Alumasc, Soprema and others.

Where a manufacturer-backed system is specified, the contractor may need to meet the relevant manufacturer's requirements for the proposed project and warranty.

Does the Manufacturer Help Specify the Roof?

On some commercial roofing projects, manufacturers can provide technical support during the specification process.

This may include considering the existing roof construction and developing a suitable system build-up for the proposed works.

The level of manufacturer involvement varies according to the project and manufacturer.

This can be particularly useful on substantial refurbishment schemes where waterproofing, insulation and complex detailing need to work together as a complete system.

Why Does the Specification Matter to the Warranty?

A manufacturer-backed warranty may depend on the roofing system being installed in accordance with the agreed specification.

Changing materials or details without considering the manufacturer's requirements could potentially affect the warranty arrangements.

This is one reason specifications matter on commercial roofing projects.

The roof isn't simply a collection of interchangeable materials selected independently according to price.

The individual components and details may have been designed to work together as part of a particular system.

Installation Can Be Just as Important as the Materials

High-quality roofing materials still need to be installed correctly.

Commercial roofs can contain numerous complicated details, including:

• Rooflights

• Outlets

• Upstands

• Penetrations

• Plant bases

• Parapets

• Changes in level

• Roof edges

These areas require appropriate detailing as part of the waterproofing system.

A manufacturer-backed specification doesn't remove the importance of good installation. Instead, the specification and installation need to work together.

Are Commercial Roofs Inspected During Installation?

Depending on the manufacturer, system and warranty arrangement, inspections may form part of the process.

These can provide an opportunity to review elements of the installation against the manufacturer's requirements.

The inspection process varies between manufacturers and projects, so clients shouldn't assume every roofing warranty includes the same inspection regime.

Where inspections form part of a proposed warranty, the requirements should be established as part of the project.

Does a Longer Warranty Automatically Mean a Better Roof?

Not necessarily.

It can be tempting to compare commercial roofing systems purely by warranty length.

For example, if one proposal offers a longer warranty period than another, it may initially appear to be the better option.

But warranty duration is only one consideration.

Clients should also look at:

• What the warranty covers

• Who provides it

• The roofing system being installed

• Exclusions and conditions

• Maintenance requirements

• The suitability of the specification

• Installation requirements

A longer warranty isn't particularly useful if the underlying system isn't appropriate for the building.

The roofing specification should come first.

What Can Affect a Roofing Warranty?

Warranty terms vary, but there can be conditions that need to be followed for the cover to remain valid.

Depending on the manufacturer or provider, these could relate to maintenance, inspections, alterations or subsequent works to the roof.

This becomes particularly important on commercial buildings because roofs often change during their service life.

New equipment may be installed, services altered or additional penetrations created.

Any future works should therefore consider the requirements of the existing roofing system and warranty.

What Happens if Someone Else Alters the Roof?

Commercial roofs frequently accommodate building services.

Air-conditioning equipment, ventilation systems, pipework and other installations may be added or altered after a refurbishment has been completed.

If another contractor subsequently cuts through or alters the waterproofing system, this can potentially affect the roof and may have implications for warranty cover.

Building owners and facilities managers should therefore understand what requirements apply before allowing later alterations to a warranted roof.

Our existing article on why rooftop plant equipment creates roofing challenges explains some of the issues that can arise when building services interact with the roofing system.

Does Maintenance Matter?

A new roof shouldn't simply be forgotten once the project is complete.

Commercial roofs can be affected by blocked outlets, debris, accidental damage, additional services and general changes to the building.

Some warranty arrangements may also contain requirements relating to inspection or maintenance.

The precise obligations depend on the warranty provider and documentation.

Building owners should retain the relevant warranty information and understand any responsibilities that continue after completion.

What Documentation Should a Client Receive?

The documentation provided at completion will depend on the project.

For a substantial commercial roofing refurbishment, relevant information may include:

• Warranty or guarantee documentation

• Details of the installed roofing system

• Manufacturer information

• Relevant completion records

• Maintenance information where applicable

These records can become useful long after the original project team has changed.

They may also help future facilities managers or contractors understand exactly what roofing system is installed.

Why Warranty Information Matters During Tendering

Warranty requirements should ideally be considered before contractors submit their final proposals rather than being introduced after the roofing system has already been selected.

If a client requires a particular type or duration of warranty, this can influence the proposed manufacturer, system and specification.

Making those requirements clear can also make tender comparisons more meaningful.

We've previously explained why roofing tenders often receive widely different prices. Differences in roofing systems, specifications and warranty arrangements can all contribute to variations between quotations.

Warranties Are Particularly Relevant to Public-Sector Projects

Councils, housing providers, schools and other public-sector organisations may need confidence that substantial roofing expenditure provides a long-term solution.

Manufacturer-backed systems and clearly defined warranty arrangements can therefore form an important part of the roofing specification.

However, warranty requirements should still be considered alongside suitability, installation quality, maintainability and whole-life value.

Our guide to public sector roofing procurement explains some of the wider considerations involved when roofing works are procured through tenders, frameworks and other public-sector routes.

What Should Clients Ask About a Proposed Roofing Warranty?

When reviewing a commercial roofing proposal, useful questions include:

• Who provides the warranty?

• What exactly does it cover?

• How long does the cover last?

• Is it a product, system or workmanship warranty?

• Are inspections required?

• Are there maintenance requirements?

• What happens if the roof is subsequently altered?

• Are there exclusions that need to be understood?

• What documentation will be provided at completion?

These questions can reveal far more than simply comparing the headline warranty period.

The Roofing System Still Needs to Be Right for the Building

A warranty should support a well-designed roofing solution rather than determine it.

The first priority should be selecting a roofing system appropriate for the existing construction, building use and project requirements.

The warranty can then form part of the overall package.

This is particularly important on refurbishment projects where the condition of the existing roof, insulation, drainage and complex details can all influence the final specification.

Commercial Roofing Across London, Essex and Kent

Premier Roofing & Construction undertakes commercial roof refurbishment and replacement projects across London, Essex, Kent and the wider South East.

We work with established roofing manufacturers and install built-up felt, single-ply and cold-applied liquid waterproofing systems across commercial, public-sector and multi-residential buildings.

Where manufacturer-backed warranties form part of a project, the applicable system, specification and warranty requirements are established for the individual scheme.