Building Act 1984: A Landlord’s Guide

The Building Act 1984 is the principal statute governing building control in England and Wales. It provides the legal framework under which the Building Regulations are made, inspections carried out, and enforcement action taken against unauthorised or non-compliant building work. The Act has been substantially amended, most significantly by the Building Safety Act 2022 which created a new regime for higher-risk buildings. This page covers when building regulations approval is required, the three approval routes (full plans, building notice, Approved Inspector), the role of the Building Safety Regulator for higher-risk buildings, the principal Approved Documents, and the penalties for unauthorised work.

What the Act does

The Building Act 1984 is the principal statute governing building control in England and Wales. It provides the legal framework under which the Building Regulations are made, inspections carried out, and enforcement action taken against unauthorised or non-compliant building work. The Act is now over 40 years old and has been substantially amended — most recently and significantly by the Building Safety Act 2022 — but its core architecture remains the foundation of the building control system.

The Act itself is short on technical content. It empowers the Secretary of State to make Building Regulations, designates “approved documents” that contain technical guidance, and creates the enforcement framework. The substantive technical requirements — fire safety, structural safety, energy efficiency, access, sanitation, ventilation — are set out in the Building Regulations 2010 and the corresponding Approved Documents A through R. The Act is the legislative skeleton; the Regulations and Approved Documents are the flesh.

For landlords, the Act’s relevance is principally indirect. Most landlords are not “building work” — they are operating existing buildings rather than constructing new ones. But the Act becomes directly relevant whenever a landlord undertakes work that requires building regulations approval: extensions, conversions, structural alterations, changes of use, electrical or gas system installations, drainage works. The cost and complexity of these works has increased substantially through the 2010s and 2020s as regulations have tightened — particularly around energy efficiency and (post-Grenfell) fire safety.

When building regulations approval is required

Building regulations approval is required whenever “building work” within the statutory definition is undertaken. The principal categories:

• The erection or extension of a building. New construction, conservatories above a defined size, extensions, garage conversions, loft conversions.
• The material alteration of a building. Structural changes, removal of load-bearing walls, replacement of major systems.
• The provision or extension of a controlled service or fitting. Heating systems, plumbing, electrical installations, drainage, ventilation.
• Material changes of use. Conversion of a single dwelling into multiple dwellings (an HMO conversion); conversion of commercial premises to residential; conversion of a residential property to a different residential category.
• Underpinning of foundations.
• Insertion of insulation into cavity walls.

Some minor works are exempt — most notably small porches, internal cosmetic alterations, repairs that do not affect controlled services. The exemptions are narrowly drawn and have tightened over time. Always check before assuming a particular project is exempt.

How approval is obtained

The Act provides three routes to obtain building regulations approval:

Full plans submission

The most thorough route. Detailed plans, specifications, and structural calculations are submitted to the local authority’s building control department. The authority reviews the submission, issues comments, and approves (sometimes with conditions). Construction proceeds with inspections at key stages — foundations, drainage, structural elements, completion. A completion certificate is issued at the end if all inspections pass.

Full plans approval is the preferred route for substantial projects. Errors are identified before construction begins, reducing the risk of expensive remedial work later. Approval typically takes 4-8 weeks and costs £400-£2,500 depending on the project size.

Building notice

A simpler route for smaller projects. The applicant submits a notice that work is intended without detailed plans. Construction begins; inspections occur as the work proceeds; problems are identified and addressed in real time. There is no formal pre-construction approval — the inspections during construction are the approval mechanism.

Building notice is suitable for small extensions, simple alterations, single-room loft conversions. It is faster and cheaper but riskier — discovered defects can require expensive remedial work mid-construction.

Approved Inspector

An alternative to using the local authority. Private companies authorised by the Construction Industry Council and registered with the Building Safety Regulator (post-2023) can act as “Approved Inspectors” — providing the same building control function as a local authority. The Approved Inspector inspects the work, issues notices, and provides the completion certificate.

Approved Inspectors are particularly used for commercial and complex projects where specialist expertise is needed. They are also commonly used by national developers for consistency across projects in different local authority areas. Cost is comparable to local authority fees.

Higher-risk buildings — the post-2022 position

The Building Safety Act 2022 substantially changed the building control framework for “higher-risk buildings” (residential buildings of 18m+ height or 7+ storeys). For these buildings:

• Building control authority is the Building Safety Regulator (BSR), not the local authority or Approved Inspector.
• Approval is required at three “Gateway” points: design, pre-construction, and pre-occupation.
• Substantial documentation requirements apply at each Gateway.
• The BSR has substantial enforcement powers including the ability to halt construction.

See our Building Safety Act 2022 guide for the higher-risk building regime in detail.

The Approved Documents

Building Regulations are supported by “Approved Documents” — official guidance providing technical detail on how to satisfy each Regulation. The current Approved Documents are:

• Approved Document A — Structure.
• Approved Document B — Fire safety. Most relevant to landlords; covers fire compartmentation, escape routes, fire-resistant construction.
• Approved Document C — Site preparation, dampness.
• Approved Document D — Toxic substances.
• Approved Document E — Resistance to sound.
• Approved Document F — Ventilation.
• Approved Document G — Sanitation, hot water safety, water efficiency.
• Approved Document H — Drainage and waste disposal.
• Approved Document J — Combustion appliances and fuel storage.
• Approved Document K — Protection from falling, collision, and impact.
• Approved Document L — Conservation of fuel and power. Covers insulation, glazing, energy efficiency.
• Approved Document M — Access to and use of buildings.
• Approved Document P — Electrical safety.
• Approved Document Q — Security in dwellings.
• Approved Document R — Physical infrastructure for high-speed electronic communications.
• Approved Document S — Infrastructure for charging electric vehicles.

Following the Approved Documents is one way to satisfy the corresponding Regulations — but not the only way. Alternative approaches that meet the same standard are permissible. In practice, most building control bodies expect Approved Document compliance unless there is specific justification for an alternative.

Penalties for unauthorised work

Carrying out building work without the required approval is a criminal offence under section 35 of the Act. The penalty regime:

• Summary conviction: fine up to £5,000.
• Daily fine for continuing offences: up to £50 per day.
• Enforcement notice from the local authority requiring remediation, demolition, or other action.
• Local authority remediation at the landlord’s expense (with substantial markup) where the landlord fails to comply with an enforcement notice.

Beyond the immediate penalties, unauthorised work creates substantial practical problems:

• Mortgage lenders typically refuse to lend on properties with unresolved building regulations issues.
• Property sales are routinely delayed or fail when buyers’ searches reveal unauthorised works.
• Insurance claims for damage relating to unauthorised work may be refused.
• HMO licence applications can fail where the licensable property has unauthorised works.

Authoritative sources

• Building Act 1984.
• Building Regulations 2010.
• Approved Documents (gov.uk).
• Our Building Safety Act 2022 guide — for higher-risk buildings.
• Our HMO setup guide — for HMO conversion building regulations.