Insurance Backed Guarantees vs Structural Warranties: What’s the Difference? 

If you’re involved in construction or property development in the UK, you’ve likely come across two forms of protection: Insurance Backed Guarantees (IBGs) and structural warranties. Both are important — but they serve very different purposes and protect against very different risks. 

Understanding the difference between an IBG and a structural warranty ensures developers, property owners, lenders, and contractors have the right cover in place. In this guide, we explain how each works, what they cover, and why many UK construction projects use both. 

What Is an Insurance Backed Guarantee (IBG)? 

An Insurance Backed Guarantee is an insurance policy that protects a contractor’s workmanship guarantee. When a contractor completes a project, they typically issue a guarantee confirming their installation or workmanship will perform as expected for a defined period. However, that guarantee is only worth anything while the contractor is still trading. 

An IBG steps in if the contractor ceases trading — through insolvency or closure — during the guarantee period. The insurer honours the terms of the original guarantee, meaning the property owner retains full protection for the guaranteed works even if the contractor no longer exists. 

What Does an IBG Typically Cover? 

IBGs are most commonly used for specialist construction elements, including: 

• Roofing systems (flat, pitched, GRP, EPDM, single ply) 

• Waterproofing and basement tanking 

• Cladding systems 

• Glazing installations 

• Damp proofing 

• Groundworks and piling 

• Other specialist building systems 

Importantly, many structural warranty providers — including mortgage lenders — require an IBG for specialist elements such as flat roofing and tanking, as these are often excluded from the structural warranty itself.  

What Is a Structural Warranty? 

A structural warranty — also known as latent defects insurance — provides long-term protection against major structural defects in a building. These warranties are typically arranged for new developments or significant structural works and usually last for 10 to 12 years from practical completion. 

What Does a Structural Warranty Cover? 

Structural warranties generally cover the key load-bearing elements of a building: 

• Foundations 

• Load-bearing walls 

• Structural frames 

• Roof structures 

• Other essential structural elements 

Structural warranties are a requirement of the majority of UK mortgage lenders before they will lend on a new build or recently converted property. They are particularly important on residential developments and provide essential protection against serious structural failure throughout the policy term. 

Insurance Backed Guarantee vs Structural Warranty: The Key Differences 

Although both relate to building works, their scope, purpose, and application are quite different. 

Scope of Cover 

A structural warranty protects the overall integrity of the building’s structure. An IBG protects the contractor’s guarantee for a specific package of works or system. For example, a structural warranty may cover structural failure within a roof structure, but it will typically not cover the roofing membrane or waterproofing system installed by a specialist subcontractor — that’s where an IBG comes in. 

Type of Work Covered 

IBGs are used for specialist installations or individual packages of work within a project. Structural warranties apply to the building as a whole. This makes IBGs particularly relevant for refurbishment projects, specialist installations, or situations where only a specific part of the building requires additional protection. 

Cost and Process 

Structural warranties typically involve technical audits, design reviews, and stage inspections during construction. As they insure the entire building structure, they are more complex and more expensive to arrange. IBGs are generally quicker and more cost-effective, as they provide insurance backing to an existing contractor guarantee without requiring the same level of inspection process. 

Duration 

Structural warranties typically run for 10 to 12 years. IBGs commonly run for up to 10 years, though the term is tied to the length of the contractor’s original guarantee. 

At a glance: 

• Structural Warranty → protects the building’s structural integrity over 10–12 years 

• Insurance Backed Guarantee → protects the contractor’s workmanship guarantee if they cease trading 

Why Many UK Construction Projects Use Both 

In practice, most developments benefit from having both a structural warranty and Insurance Backed Guarantees in place. The two forms of cover work alongside each other rather than duplicating protection. 

For example, a developer may arrange a 10-year structural warranty for the building, while specialist contractors — such as roofing or waterproofing installers — provide longer-term guarantees for their systems, each backed by an IBG. In many cases, structural warranty providers or lenders will specifically require IBGs for specialist works to ensure those guarantees remain valid and enforceable throughout the protection period. 

Without an IBG in place for specialist elements, a warranty application may be delayed, a mortgage refused, or a property sale unable to progress. 

Do I Need an Insurance Backed Guarantee or a Structural Warranty? 

The answer depends on the nature of your project. As a general guide: 

• If you are developing a new residential or commercial building, you will almost certainly need a structural warranty — it is required by most mortgage lenders. 

• If specialist contractors are involved in works such as flat roofing, waterproofing, cladding, or tanking, an IBG is likely to be required by your warranty provider or lender. 

• If you are a contractor looking to add credibility and protection to your workmanship guarantees, an IBG demonstrates confidence in the quality of your work. 

• If a property is being sold or refinanced and specialist works were completed without an IBG at the time, a retrospective IBG may be needed to satisfy legal and lending requirements. 

 Arrange an Insurance Backed Guarantee with Advantage 

At Advantage we help developers, contractors, property owners, and lenders arrange Insurance Backed Guarantees that meet compliance requirements and provide long-term reassurance. 

We operate nationally and are trusted by some of the UK’s leading developers to provide specialist construction insurance solutions. 

To discuss how an IBG can support your project, or to find out more about our full range of construction insurance products, get in touch with our team today.