Building Warranty Guide for Blocks of Flats
A comprehensive guide to building warranties for blocks of flats, covering NHBC Buildmark, LABC Warranty, Premier Guarantee, and other warranty providers. Understand defect liability periods, structural warranties, developer snagging obligations, and how to make a building warranty claim for your development. Learn about latent defects, limitation periods, and the Building Safety Act implications for new builds.
What Is a Building Warranty?
A building warranty is an insurance-backed guarantee that protects buyers and leaseholders of new build properties against defects in design, materials, and workmanship. For blocks of flats, the warranty covers both the individual units and the communal areas, structure, and shared services of the building. Most mortgage lenders require an approved building warranty to be in place before they will lend on a new build property, making it a fundamental part of the development process.
The standard building warranty lasts for ten years from the date of completion and is typically split into two phases: a defect liability period (usually the first two years) during which the developer is responsible for rectifying defects, and a structural warranty period (years three to ten) during which the warranty provider insures against major structural problems. Understanding how these phases work is essential for managing agents, residents management companies, and leaseholders in new build developments.
This guide explains the types of building warranty available, how to make claims, common defects in new build blocks, and what happens when the warranty period ends. For information about managing the insurance requirements of a block of flats, see our insurance claims guide.
Types of Building Warranty for Blocks of Flats
Several warranty providers operate in England and Wales, each offering broadly similar cover but with differences in terms, exclusions, and claims processes. The most common building warranty providers for blocks of flats are set out below.
NHBC Buildmark
The NHBC Buildmark warranty is the most widely used new build warranty in the UK. It provides a two-year builder warranty period, during which the developer must remedy defects that breach NHBC standards, followed by eight years of structural insurance cover provided by the NHBC. The NHBC also carries out inspections during construction to verify compliance with their technical standards. For blocks of flats, the Buildmark policy covers both individual units and the common parts of the building.
LABC Warranty
LABC Warranty is backed by local authority building control and provides a similar ten-year structure to the NHBC. It offers a two-year defect insurance period followed by eight years of structural defect cover. LABC Warranty works closely with local authority building control surveyors who inspect the development during construction, providing an additional layer of quality assurance beyond the warranty provider's own checks.
Premier Guarantee, ICW, and Protek
Premier Guarantee, ICW (Independent Complaint Warranties), and Protek Warranty are alternative providers that offer ten-year warranties for new build developments. Each has its own underwriting arrangements, technical standards, and claims procedures. While less prevalent than NHBC, these providers are accepted by most major mortgage lenders and offer comparable levels of structural cover. Managing agents should familiarise themselves with the specific terms of whichever warranty applies to their development.
Defect Liability Period vs Structural Warranty
Understanding the distinction between the defect liability period and the structural warranty is critical for managing agents and leaseholders in new build blocks of flats. The two phases operate differently and require different approaches when defects are discovered.
The Defect Liability Period (Years 1-2)
During the defect liability period, which typically lasts for the first two years after completion, the developer is directly responsible for rectifying any defects in workmanship, materials, or design that do not meet the warranty provider's technical standards. This includes both individual flat defects and issues affecting the communal areas. The managing agent should maintain a comprehensive snagging log, report all defects to the developer promptly, and track the developer's response. If the developer fails to carry out remedial work, the warranty provider can be asked to intervene.
The Structural Warranty (Years 3-10)
From year three onwards, the structural warranty provides insurance-backed cover against major structural defects. This typically covers the failure of load-bearing elements, water ingress caused by defects in the external envelope, subsidence, and other defined structural issues. Importantly, the structural warranty does not cover cosmetic defects, routine maintenance, or items that should have been reported during the defect liability period. Claims are made directly to the warranty provider, not the developer, and the provider will carry out an inspection before accepting or declining the claim.
The transition from the defect liability period to the structural warranty phase is a critical moment for any new build block. The managing agent should conduct a thorough inspection before the end of year two to ensure all known defects are reported to the developer before responsibility shifts to the warranty provider. For guidance on managing new build developments, see our new build management guide.
Developer Snagging and Defect Rectification
Snagging is the process of identifying defects, incomplete work, and substandard finishes in a new build property before or shortly after handover. For blocks of flats, snagging should cover both the individual units and all communal areas, plant rooms, external landscaping, car parks, and shared services. A professional snagging inspection is strongly recommended.
The Snagging Process
The snagging process should begin with a systematic inspection of every area of the building, recording all defects with photographs and detailed descriptions. Common snagging items in blocks of flats include poorly finished paintwork, scratched glazing, misaligned doors and cupboards, incomplete sealant work, and defective mechanical and electrical installations. For the communal areas, the managing agent should also check fire safety installations, emergency lighting, access control systems, lifts, and drainage. All snagging items should be compiled into a formal report and submitted to the developer for rectification.
Developer Obligations
During the defect liability period, the developer has a contractual and warranty obligation to remedy reported defects within a reasonable timeframe. Managing agents should set clear deadlines for rectification, maintain a detailed tracker of all reported items and their status, and escalate to the warranty provider if the developer is unresponsive. It is also important to ensure that remedial works carried out by the developer are completed to an acceptable standard and do not introduce new defects. For developments where the developer is also the freeholder, there may be conflicts of interest that the managing agent must navigate carefully.
Common Defects in New Build Blocks of Flats
New build blocks of flats are susceptible to a range of defects, some of which may not become apparent until months or years after completion. Managing agents and leaseholders should be aware of the most common issues so that they can be identified and reported promptly, ideally within the defect liability period.
- Water ingress through external walls, windows, balconies, and flat roofs caused by poor sealing or defective cladding installation
- Heating and hot water system failures, particularly in developments with communal heating or district heat networks
- Drainage defects including incorrectly graded pipework, blocked drains, and inadequate surface water management
- Cladding and external wall system defects, including non-compliant materials and poor installation practices
- Defective fire stopping between compartments, risers, and service penetrations, compromising fire safety
- Poor sound insulation between flats failing to meet Building Regulations Approved Document E standards
- Cracking in internal plasterwork, screeds, and external render caused by building movement or inadequate curing
- Malfunctioning lifts, door entry systems, ventilation units, and other communal mechanical and electrical installations
- Substandard landscaping, drainage, and external works in car parks and communal gardens
Many of these defects have direct implications for health and safety in the building. For cladding-specific issues, see our detailed cladding remediation guide.
Handover from Developer to Managing Agent
The handover from the developer to the managing agent is one of the most important stages in the life of a new build block of flats. A poorly managed handover can result in missing documentation, unresolved defects, and uncertainty about warranty coverage that affects the building for years to come.
Essential Handover Documents
The managing agent should ensure that the developer provides a comprehensive handover pack including the building warranty policy documents, as-built drawings, operation and maintenance manuals for all mechanical and electrical installations, fire risk assessment, health and safety file, planning conditions and compliance records, and contact details for all subcontractors. The warranty documentation is particularly important as it sets out the terms, coverage, exclusions, and claims procedures that will govern the building for the next ten years.
Warranty Implications for Service Charges
The existence of a building warranty has direct implications for the service charge during the early years of a development. Repairs that are covered by the warranty should not be funded through the service charge, and the managing agent must diligently pursue the developer or warranty provider for all warranted defects. Failing to do so results in leaseholders paying for repairs that should be borne by the developer. The service charge budget should reflect the reduced maintenance liability during the warranty period while building an appropriate reserve fund for when the warranty expires.
Latent Defects and Limitation Periods
Latent defects are defects that are not immediately apparent and may only become evident months or years after the building is completed. These are distinct from patent defects, which are visible at the time of inspection. In blocks of flats, latent defects can include hidden structural issues, concealed waterproofing failures, defective fire stopping within walls and floors, and inadequate foundations.
Limitation Act 1980
Under the Limitation Act 1980, claims for breach of contract must be brought within six years of the breach, while claims under a deed (which includes most leases) must be brought within twelve years. For claims in tort (negligence), the limitation period is six years from the date the damage occurred, or three years from the date the claimant became aware of the defect under the latent damage provisions. These limitation periods can extend the window for bringing claims well beyond the ten-year warranty period, particularly where defects were concealed or could not reasonably have been discovered earlier.
Defective Premises Act 1972
The Defective Premises Act 1972 imposes a duty on any person taking on work in connection with the provision of a dwelling to ensure that the work is carried out in a professional manner with proper materials and so that the dwelling will be fit for habitation. The Building Safety Act 2022 amended the Defective Premises Act to extend the limitation period to fifteen years for retrospective claims and thirty years for prospective claims from the date of completion. This is a significant development for blocks of flats with serious structural defects, as it provides a route for claims long after the building warranty has expired.
Managing agents should be aware of these limitation periods and ensure that professional advice is sought promptly when latent defects are discovered. For guidance on managing major works that may arise from defect rectification, see our major works guide.
Building Safety Act Implications for New Builds
The Building Safety Act 2022 has introduced fundamental changes to the regulatory landscape for new build blocks of flats, particularly those classified as higher-risk buildings (over 18 metres or seven storeys). The Act establishes a new regulatory framework overseen by the Building Safety Regulator within the Health and Safety Executive, creating obligations that interact directly with building warranty provisions.
Gateway Process
The Act introduces a three-gateway regulatory process for higher-risk buildings. Gateway one covers the planning stage, gateway two covers the construction stage (replacing the traditional building control sign-off), and gateway three covers the completion and handover stage. Developers must demonstrate compliance at each gateway before proceeding, and the golden thread of building information must be maintained throughout the building's lifecycle. This enhanced scrutiny should reduce the incidence of construction defects in new buildings, complementing the protections offered by the building warranty.
Developer Remediation and Leaseholder Protections
The Building Safety Act includes significant leaseholder protections, including provisions that prevent costs of remedying historical building safety defects from being passed to qualifying leaseholders through the service charge. Developers who are members of the government's remediation scheme have committed to remediating life-critical fire safety defects in buildings they developed. These protections operate alongside and in addition to any building warranty cover, providing multiple routes for leaseholders to seek redress for defects. For further information about cladding remediation and fire safety, see our dedicated guide.
Frequently Asked Questions About Building Warranties
What building warranties are available for blocks of flats?
Several building warranty providers offer cover for blocks of flats in England and Wales. The most widely recognised is the NHBC Buildmark warranty, which provides a two-year builder warranty period followed by eight years of structural insurance cover. Other major providers include LABC Warranty, which is backed by local authority building control and offers similar two-plus-eight-year cover, Premier Guarantee, which is underwritten by MD Insurance Services, ICW (Independent Complaint Warranties), and Protek Warranty. Each provider has its own terms, exclusions, and claims processes, but all broadly follow the same model of a short initial defect liability period during which the developer is responsible for remedying faults, followed by a longer structural warranty period during which the warranty provider insures against defined structural defects. Mortgage lenders typically require one of these approved warranties to be in place before lending on a new build property.
What is the difference between a defect liability period and a structural warranty?
The defect liability period and the structural warranty are two distinct phases of cover under a building warranty. The defect liability period, which usually lasts for the first two years after completion, places the responsibility for rectifying defects directly on the developer or builder. During this period, the developer must remedy any defects in materials or workmanship reported by the leaseholder or managing agent. The structural warranty, which typically runs from year three to year ten, is an insurance-backed guarantee provided by the warranty provider rather than the developer. It covers major structural defects such as failure of load-bearing elements, water ingress caused by structural issues, and subsidence. The structural warranty does not cover cosmetic issues, general wear and tear, or items that should have been reported during the defect liability period. Understanding the distinction is essential for managing agents and leaseholders because it determines who to contact and what process to follow when a defect is discovered.
How do you make a claim under an NHBC warranty for a block of flats?
To make a claim under an NHBC Buildmark warranty for a block of flats, the process depends on whether the defect falls within the initial two-year builder warranty period or the subsequent structural insurance period. During the first two years, the claim should be directed to the developer, who is obliged to rectify any reported defects in line with NHBC standards. If the developer fails to carry out the work or disputes the defect, the NHBC can be asked to intervene through its resolution service. From year three onwards, claims are made directly to the NHBC under the structural insurance element of the policy. The managing agent or residents management company should submit the claim in writing, providing full details of the defect, photographic evidence, and any reports from surveyors or engineers. The NHBC will then carry out an inspection to assess whether the defect falls within the scope of the warranty. Claims must relate to defects that meet the NHBC definition of a structural issue, and cosmetic or maintenance-related problems are excluded.
What common defects are found in new build blocks of flats?
New build blocks of flats frequently present a range of defects during the early years of occupation. Water ingress is among the most common, often caused by poorly sealed windows, inadequate balcony drainage, defective flat roofing, or faulty cladding installation. Heating and hot water system failures are also prevalent, particularly in developments with communal heating systems or heat networks where the design or commissioning has been inadequate. Drainage issues, including blocked or incorrectly graded pipes, can cause persistent problems for ground-floor flats and communal areas. Cladding defects have received significant attention following the Grenfell Tower tragedy, with many new builds found to have non-compliant or poorly installed external wall systems. Other common defects include poor sound insulation between flats, cracking in plasterwork and screeds, defective fire stopping between compartments, malfunctioning door entry and access control systems, and substandard finishes in communal areas. A thorough snagging process at handover is essential for identifying these issues before the defect liability period expires.
Who is responsible for repairs during the warranty period?
Responsibility for repairs during the warranty period depends on the nature of the defect and the stage of the warranty. During the defect liability period, which is typically the first two years, the developer is directly responsible for remedying defects in workmanship and materials. The managing agent or residents management company should report all defects to the developer in writing and maintain a detailed log of reported issues and the developer response. From year three onwards, responsibility shifts to the warranty provider for structural defects covered by the insurance element of the warranty. However, routine maintenance and repair of items not covered by the warranty remain the responsibility of the managing agent, funded through the service charge. It is important that the managing agent distinguishes between warranty-covered defects and maintenance issues, as incorrectly attributing costs to the service charge when they should be claimed under the warranty can result in leaseholders paying for repairs that the developer or warranty provider should fund.
What happens when the building warranty expires?
When the building warranty expires, typically after ten years from the date of completion, the responsibility for all repairs and maintenance falls entirely on the leaseholders through the service charge. There is no longer a developer or warranty provider to fall back on for structural defects, which makes it essential that any outstanding warranty claims are submitted before the expiry date. The managing agent should carry out a comprehensive building survey in the final year of the warranty to identify any latent defects that may be covered. Once the warranty has expired, leaseholders may still have recourse against the developer for latent defects under the Limitation Act 1980, which allows claims for breach of contract within six years or claims in tort for up to fifteen years from the date the building was completed under the Defective Premises Act 1972 as amended by the Building Safety Act 2022. The managing agent should also ensure that a robust reserve fund is in place to cover major works that may be needed once warranty protection is no longer available.
Need Help With Building Warranty Issues?
Whether you are a leaseholder dealing with new build defects, a director navigating the building warranty claims process, or a residents management company taking over from a developer, Block is here to help. Our experienced team manages building warranty claims, developer snagging, and defect rectification across hundreds of new build developments nationwide.