Why this guide exists
If you are building a new home, converting a barn, or undertaking a major renovation that crosses into "structural alteration" territory, you are likely to encounter one of two insurance products that require professional surveys as part of the issuance: a structural warranty (often called "build warranty" or by the provider's name — NHBC, Premier Guarantee, Build-Zone, etc.) and a latent defects insurance policy. Both are 10-year covers. Both are required by most mortgage lenders for new-build properties. Both are coordinated with the surveyor.
This guide explains what each insurance product covers, what surveys they require, and how the partner-referral model works when the buyer needs a RICS Building Survey (Level 3) to support an insurance application. Icelabz does not deliver the RICS Level 3 in-house; we work with a trusted RICS-regulated partner for that. We earn a small referral fee if you book through our recommendation; the price you pay is the same as going direct.
What a structural warranty is (and is not)
A structural warranty is a 10-year insurance policy that covers the cost of fixing major structural defects in a new-build or recently-converted property. It is issued by one of a handful of UK providers — the most common being NHBC, Premier Guarantee, Build-Zone, LABC Warranty, and Global Home Warranties. The provider inspects the property at key stages during construction and issues the policy on completion.
What the warranty covers:
- Major structural defects (foundations, walls, roof structure, load-bearing elements)
- Defects in the waterproof envelope (damp-proof course, weather-tightness)
- Defects in the building services that were part of the new build
What it does not cover:
- Wear and tear
- Maintenance issues
- Damage caused by the homeowner
- Cosmetic defects
- Subsidence caused by the homeowner's actions (e.g. planting trees too close to foundations)
For most mortgage lenders, a structural warranty from a recognised provider is mandatory for new-build properties. Without it, the mortgage offer is conditional on alternative security, which often means the buyer cannot proceed.
What the warranty provider requires from the surveyor
The structural warranty provider does not deliver surveys in-house. They require:
- Stage inspections during construction (typically 4–6 stages depending on the provider: foundations, damp-proof course, superstructure, pre-plaster, completion). These are usually delivered by a RICS-regulated surveyor or a Building Control inspector.
- A measured building survey for design verification on conversions (barn conversions, large extensions, change-of-use). The provider needs to verify that the as-built structure matches the design drawings.
- A RICS Building Survey (Level 3) on completion for some providers, particularly on conversions and major renovations.
The surveys the warranty provider commissions are paid for by the developer (for new-build) or by the homeowner (for self-build or conversion). They are not the buyer's surveys; they are a condition of the warranty being issued.
What a latent defects insurance policy is
A latent defects insurance policy is a 10-year cover for defects that were not visible at the time of construction or completion, that would not be discovered by a reasonable inspection, and that cause the building to be unfit for purpose. It is more comprehensive than a standard structural warranty in some respects, and it is often used in place of a structural warranty for conversions, change-of-use, and major renovations where the standard warranty providers won't issue.
Common scenarios in 2026:
- Barn conversions — most warranty providers won't cover, latent defects is the standard.
- Office-to-residential conversions — same situation.
- Major renovations where more than 25% of the building is being altered — provider-by-provider, latent defects is often the right answer.
Latent defects policies are issued by specialist insurers. The premium is typically 1.0–1.5% of the rebuild cost. For a £500,000 rebuild, that's £5,000–£7,500 — paid once, at completion.
The role of the insurance broker
The insurance broker is the intermediary between the homeowner/developer and the warranty/latent-defects provider. They:
- Identify the right provider for the project (NHBC for new-build, latent defects for conversions)
- Submit the application
- Coordinate the stage inspections
- Issue the policy on completion
For self-build and conversion projects, the broker's role is more important than for new-build: the broker advises on which provider is likely to accept the application (some are stricter than others on subsidence history, listed status, etc.). The broker's fee is typically 0.5–1.0% of the premium.
The 2026 cost ranges (UK)
| Product | Typical 2026 cost | Delivered by | When | |---------|-------------------|--------------|------| | Structural warranty (new-build) | £2,000–£6,000 (developer-paid, embedded in price) | NHBC, Premier Guarantee, etc. | Every new-build sale | | Latent defects insurance (conversion) | 1.0–1.5% of rebuild cost | Specialist insurers | Conversions, major renovations | | Stage inspections (4–6 stages) | £150–£300 per stage | RICS surveyor or Building Control | During construction | | Measured building survey | £400–£1,500+ | Icelabz (us) | Conversions, design verification | | RICS Building Survey (Level 3) | £600–£1,500+ | RICS partner | Conversions, older properties |
The four products are independent. A typical self-build or conversion will commission all four.
Cross-sell FAQ
Does Icelabz deliver the stage inspections? No. Stage inspections for warranty providers are delivered by RICS surveyors or Building Control inspectors. We deliver the measured building survey that goes alongside them.
Can the warranty provider reject an application? Yes. Common reasons: the site has subsidence history, the design uses non-standard construction, the developer has no track record, the property is listed and the provider won't cover listed buildings. The broker's job is to pre-screen before submission.
What if the buyer is doing a self-build — do they need both a warranty and a latent defects policy? Usually one or the other, not both. For a new-build self-build, the standard structural warranty is the right answer. For a conversion, latent defects is the right answer. The broker will advise.
How does the RICS Building Survey (Level 3) fit in? For older properties or for conversion projects, the warranty/latent-defects provider often asks for a Level 3 survey to confirm the existing structure. We work with a RICS-regulated partner for Level 3. Same price as direct; small referral fee on the introduction.
Transparency
Icelabz delivers measured building surveys, topographical surveys, 3D laser scanning, and other design-feed surveys in-house. We do not deliver RICS Building Surveys, structural warranties, or latent defects insurance in-house. For RICS Level 3 surveys, we work with a trusted RICS-regulated partner. If you book through us, we earn a small referral fee; the price you pay is the same as if you went direct. If you would rather book the RICS survey yourself, here is the RICS Find a Surveyor directory.
If you need a Measured Building Survey (the floor plans, elevations, sections, or 3D model that the architect uses to design an extension, conversion, or renovation), we deliver that in-house. Get a fixed quote in 24 hours.