17 July 2025

Guide to self-build warranties and insurance

By Self Build Zone
self-build warranty site insurances

Complete Guide to Self-Build Warranties (Self-Build Insurance & Warranty).

For every bespoke self-build, conversion or extension project in the UK, a Self-Build Warranty is essential. Mortgage lenders typically insist on a 10-year Structural Warranty from completion, and most buyers expect cover when purchasing a self-build home after it’s finished.

A Structural Warranty protects you from latent defects in design, workmanship and materials, including issues in drainage, waterproofing, chimneys, and structural elements. These latent defects often do not become apparent until years later, and can be extremely costly to rectify without insurance.

Self Build Insurance vs Structural Warranty: What’s the Difference?

Type of Cover When Active What It Covers Why You Need It
Site Insurance During the build (individual policy up to 24 months but can be extended if needed). Fire, theft, storm, public liability, contract works, injuries Protects your project from plot purchase until completion.
Structural Warranty From completion, up to 10 years Latent defects in design, workmanship or material Required by most lenders and transfers with the property.

You generally organise both tasks before breaking ground, usually about two weeks before the start of work on the site, for seamless protection and scheduling of key inspections.

What does a Self-Build Warranty cover?

A reputable provider like Self-Build Zone offers 10-12 year Structural Warranty insurance, underwritten by ‘A’ Rated insurers, and accepted by virtually all UK mortgage lenders.

Cover includes:

  • Rebuilding or repairing major defects across structural elements and the waterproof envelope
  • Rectifying issues in drainage systems, chimneys or flues affecting safety
  • Meeting legal or building regulations costs
  • Fees for professional services and debris removal
  • Temporary accommodation if your home becomes uninhabitable

It excludes defects in retained or existing structures unless specifically covered.

Benefits of a Self-Build Warranty over architect certificates

  • Longer term protection: Covers defects for up to 12 years, compared to an architect’s professional certificate (PCC), which only covers six years and relies on proving negligence
  • Fully transferable: If the property is sold, the warranty transfers automatically to a successor after you have lived in it for at least 12 months, helping to confirm your self-build status for CIL exemption
  • Straightforward claims process: Unlike PCC disputes, the warranty allows you to claim without proving professional fault.

Choosing the right provider: why Self-Build Zone?

  • Trusted experience since 2002: Over two decades specialising in self-build insurance and warranties
  • ‘A’ Rated insurers only: Gives confidence in claims settlement and continuity, even if one insurer collapses
  • Mortgage lender acceptance: Recognised by nearly all UK lenders, including via the UK Finance-approved list.

When to arrange cover & planning ahead

  • Organise Site Insurance and Structural Warranty before the first spade hits soil.
  • Aim to secure both around two weeks before the start of construction, to accommodate technical inspections at key build stages (foundations, drainage, etc.) and avoid premium hikes or retrospective charges
  • Retrospective warranties are available but significantly more expensive and may be limited in availability.

Typical costs & what to expect

  • Budget approximately 1% of the total build cost for a Structural Warranty. Note, this is paid before work begins
  • If warranties are purchased after the build starts, premiums rise due to missed inspections or additional survey requirements.

Final Tips: Protecting your self-build investment

It’s essential to secure both site insurance and a Structural Warranty before construction begins to ensure full protection from day one. Make sure your policies are approved by mortgage lenders and backed by an ‘A’ Rated insurer to safeguard your investment and support future saleability. Always keep all documentation and certificates safe, as they’ll be required for any claims or when selling the property.

With the right self-build insurance during construction and a robust Self-Build Warranty thereafter, you can confidently embark on your project knowing your investment is safeguarded—now and for years to come.

For tailored advice and quotes from Self-Build Zone, explore the rest of our website or contact our team.

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