SEO Slug: when-do-you-need-building-regulations-approval-uk Meta Title: When Do You Need Building Regulations Approval in the UK? | RCB Design & Build
When Do You Need Building Regulations Approval in the UK?
Building Regulations approval is one of those subjects that confuses a lot of homeowners. It's separate from planning permission, applies to a different range of works, and has its own submission process and consequences for non-compliance.
Here's a practical guide to when it applies and what you need to know.
What Building Regulations actually cover
Planning permission controls whether you can build something — its size, design, visual impact, and use.
Building Regulations control how it's built — structural safety, fire safety, thermal performance, ventilation, drainage, energy efficiency, and accessibility.
You can need both, either, or neither, depending on the project. The two systems are entirely separate.
When Building Regulations approval is required
Building Regulations approval is required for most structural, M&E, and fabric-changing works. The key categories include:
Extensions and new structures — all extensions, conservatories (beyond a certain size), and new outbuildings that are habitable require Building Regulations approval. The structure, insulation, drainage, and fire-separation all fall within the regime.
Loft conversions — always require Building Regulations approval, regardless of whether planning permission was needed. This covers the new floor structure, fire safety (including protected escape route), structural alterations to the roof, and thermal performance of the new space.
Structural alterations — removing or altering any structural wall, beam, column, or foundation requires approval. This includes chimney breast removals, which are a commonly overlooked item.
Electrical work — most fixed electrical installation work in dwellings falls under Part P of the Building Regulations. Self-certification by a registered electrician (NICEIC or similar) is the most common route for compliance.
Plumbing and heating — new boilers, unvented hot water cylinders, and certain plumbing installations require Building Control notification. Self-certification routes exist for registered Gas Safe and APHC members.
Re-roofing — if more than 25% of the roof is being re-covered, Building Regulations apply to ensure insulation standards are maintained.
Thermal fabric improvements — replacement windows, external wall insulation, and cavity wall insulation are all subject to Building Regulations requirements for thermal performance.
Works that typically don't require Building Regulations approval
Some works are exempt, including:
Small conservatories under a certain size, provided they're separated from the main house by a door with glazing
Most decorative or like-for-like replacement works
Minor repairs that don't affect structural elements, services, or thermal performance
Garden structures that are not habitable
The two main submission routes
Full Plans application — you submit detailed drawings and specifications before work starts. Building Control approves the plans, and then inspects at key stages during construction. This is the safest route for complex projects because any design issues are identified before the build, not during it.
Building Notice — you notify Building Control and begin work without submitting full plans. Inspectors attend site at various stages to check compliance. This is quicker to set up but riskier, because it relies on the contractor working correctly without pre-approved plans.
What happens if you don't get Building Regulations approval
Carrying out notifiable work without Building Regulations approval creates a serious problem when you sell. Solicitors acting for buyers will routinely ask for a Completion Certificate, and if there isn't one, the absence of it will need to be explained or insured.
Some buyers and their lenders will walk away. Others will ask for an indemnity insurance policy — which covers the risk of the local authority taking enforcement action, but does not confirm that the work was done to a safe standard.
The safer position is always to get the approval in place before works start and secure the Completion Certificate before they finish.
Need help navigating Building Regulations for your project? RCB manages Building Regulations coordination as part of our principal contractor scope — including submission, inspection management, and Completion Certificate sign-off.
Call us on +44 7359 872594, email contact@rcbgroup.co.uk, or visit rcbgroup.co.uk.
Kind regards, Vasi J. & rcbGroup team contact@rcbGroup.co.uk www.rcbGroup.co.uk +44 7359 872594 | +44 7448 189592 FMB | TrustMark | Checkatrade | TrustATrader Verified. Insured. Trusted.