What Is a Contractor's Liability for Defects — Workmanship, Materials, and Latent Defects

When construction work is complete and the client takes over their property, that is rarely the final chapter in the relationship between client and contractor. Defects can emerge — some immediately, some months or years later. Understanding the legal framework around defect liability matters enormously, both for clients seeking remedies and for contractors managing their exposure. This post explains the key legal distinctions, the applicable time limits, and what a properly structured contract should provide.

Two Categories: Patent Defects and Latent Defects

The law draws a fundamental distinction between two kinds of defect.

Patent defects are defects that are discoverable on reasonable inspection at the time of practical completion — a crack in the render, a sticking door, poorly fitted joinery, a roof window that does not seal properly. A client who accepts practical completion without noting these defects in a snagging list takes a degree of risk. Most standard contracts allow the client to prepare a snagging list at practical completion, and the contractor is then obliged to remedy those items within an agreed period.

Latent defects are defects that were not discoverable at practical completion and only manifest later — rising damp in a new extension, a structural movement that emerges over time, a flat roof that fails after a period of weathering. Latent defects are the more complex legal problem, because by the time they become apparent the contractor may be long gone, the contract may have been forgotten, and the client may not know who to pursue or how long they have.

Common Law: The Duty of Care in Tort

A contractor owes a duty of care in the manner in which they carry out their work. Where a contractor carries out work negligently and causes damage — structural damage, water ingress, injury — the client (and potentially third parties) may have a claim in tort for negligence, regardless of whether a written contract exists.

The applicable limitation periods under the Limitation Act 1980 are: - Section 2: a claim in negligence (tort) must be brought within 6 years from the date on which the cause of action accrued — typically the date on which damage first occurred, which in a latent defect case may be long after the work was done. - Section 14A: where the claimant did not know and could not reasonably have known about the damage, the 6-year period runs from the date of knowledge — but the long-stop is 15 years from the date of the negligent act, under section 14B.

This gives a potential maximum window of 15 years in tort, which is significant for structural latent defects.

Contract Law: Limitation from the Date of Breach

If a written contract governs the relationship — which it should for any substantial construction project — the limitation period runs from the date of breach, which is usually either the date of the defective work or the date of practical completion (courts take different views depending on the nature of the defect and the contract terms).

The standard limitation periods are: - 6 years if the contract is a simple contract (signed under hand) - 12 years if the contract is executed as a deed — that is, signed by the parties and witnessed, with the words "executed as a deed" included

For significant residential projects, executing the contract as a deed gives the client a materially longer window to pursue claims for latent defects. This is a meaningful protection worth seeking.

The Defects Liability Period (DLP)

Most construction contracts — whether JCT standard forms or bespoke contracts — include a Defects Liability Period (sometimes called a Rectification Period). This is typically 6 to 12 months following practical completion. During this period:

If any defect appears that is attributable to faulty workmanship, defective materials, or non-compliance with the contract, the contractor is obliged to return and make it good at no cost to the client.
At the end of the DLP, a final inspection takes place. Any outstanding defects are identified, and if the contractor fails to remedy them, the client is entitled to have the work done by others and deduct the cost from any retention monies still held (or pursue a claim).

The DLP is a contractual mechanism — it sits on top of, and does not replace, the common law and statutory rights described above. It is the most practical and immediate protection a client has in the months after completion.

What is not covered by the contractor's defect liability: - Fair wear and tear — normal deterioration from use over time - Damage caused by the client — misuse, modifications, or failure to maintain - Materials that the client supplied — if the client specified and supplied their own materials, the contractor's liability for defects in those materials is limited, unless the contractor failed to flag concerns about suitability

Building Regulations and Enforcement of Non-Compliance

Compliance with Building Regulations is a matter of public law, separate from the private law relationship between client and contractor. Where works were notifiable and subject to Building Regulations, non-compliance can be enforced by the Building Control Authority in two ways:

Section 36 of the Building Act 1984 allows the LPA to serve a notice requiring removal or alteration of non-compliant work within 12 months of completion. This is the standard enforcement window.

Dangerous structures are treated differently. Where non-compliant works create a danger, enforcement action can be taken at any time — there is no limitation period. A rogue contractor who installs a structurally defective beam and disappears cannot rely on the passage of time as a protection if the result is a dangerous building.

Building Control sign-off does not guarantee that all work is defect-free — inspectors check compliance at defined stages, not every element — but a completion certificate provides evidence that the notifiable works were inspected and met regulations at the time.

New Home Warranties: NHBC Buildmark

The NHBC Buildmark warranty is a 10-year structural warranty available to new homes registered with the NHBC. It covers defects in the structure and weatherproofing of the home, but it applies to newly built homes, not renovation or extension works. A contractor carrying out a loft conversion or extension to an existing property does not provide an NHBC warranty — and clients should not assume otherwise.

For renovation and extension works, the protections are the contract, the DLP, and the statutory limitation periods described above. Some contractors offer independent structural warranties for specific elements — worth asking about for significant works.

What to Do if a Defect Appears

If a defect becomes apparent after practical completion:

Notify the contractor in writing — clearly describe the defect, its location, and when it was first noticed. Written notice is essential. A WhatsApp message is better than nothing; a formal letter is better.
Allow the contractor reasonable time to inspect and respond. They have a right to inspect before any remedial work is done by a third party — carrying out repairs without giving them an opportunity to inspect may compromise your claim.
Keep evidence. Photographs, video, moisture meter readings, any reports you receive. Do not dry out damp, paint over cracks, or otherwise alter the defect before it has been inspected and documented.
Commission an independent surveyor's report if the contractor disputes liability or fails to respond. A surveyor's report that identifies the cause of the defect and links it to the contractor's work is the foundation of any claim.
Seek legal advice if the contractor denies liability or the defect is serious. For lower-value claims, the Small Claims Court (up to £10,000) or Fast Track (up to £25,000) may be appropriate. For structural defects, the amounts involved usually take the matter to the Multi-Track.

At RCB: A DLP in Every Contract, Documentation Throughout

We include a Defects Liability Period in all our contracts because it protects both parties. The client has a clear, contractual right to call us back within the DLP period. We have a clear, contractual right to inspect and remedy before a third party is brought in. That structure means defects — which occur on every project, regardless of care taken — are managed professionally rather than becoming disputes.

Our completion documentation, including sign-off records, Building Control certificates, and handover packs, provides the evidentiary trail that benefits both sides. Proper documentation is how we protect relationships after the scaffolding comes down.

RCB Design & Build | A2Z Principal Contractors | rcbgroup.co.uk Contact us to discuss contract structures, defects liability, and how we protect clients and our business on every project.