What Drawings Are Needed for Building Control Approval?
March 2026
If you’re planning building work on your home, you’ve probably heard that you’ll need “building control approval.” It’s often mentioned in the same breath as planning permission, but the two serve very different purposes. Planning is concerned with how your project looks and how it affects the surrounding area. Building control is about how it’s built, whether it’s structurally sound, safe, energy-efficient and compliant with the UK Building Regulations.
One of the most common questions homeowners ask is: what drawings do I actually need? The short answer is that building control requires detailed technical drawings that clearly demonstrate compliance. These are not just layout sketches or planning visuals. They are working documents that explain how your project will be constructed and how it will meet safety and performance standards.
The exact requirements vary depending on the scope of work, but there are some consistent elements across most projects.
The Core Drawings Most Projects Require
Every building control submission starts with a clear set of architectural drawings. These provide the framework for assessing compliance.
Location plan
This shows where your property sits in relation to surrounding buildings and boundaries. It confirms the site of the proposed works and provides context for the inspector reviewing the application.
Existing and proposed floor plans
These are essential. They show what currently exists and what is changing. If you’re removing a wall, adding an extension, converting a loft or reconfiguring rooms, it all needs to be clearly illustrated. Room uses, dimensions, wall thicknesses and structural changes should be easy to understand at a glance.
Elevations
Elevations show the external faces of the building and indicate heights, window and door positions, and overall proportions. For building control, they help demonstrate compliance with areas such as fire escape windows, structural alignment and roof heights.
These drawings form the backbone of the submission. However, on their own, they are rarely enough.
Technical Sections and Construction Details
This is where building control drawings move beyond general layout and into true compliance territory. Sections and detail drawings explain how the building is physically put together.
Cross-sections cut through the building to reveal:
Foundation design and depth
Floor build-ups and insulation layers
Wall construction and cavity insulation
Roof structure and ventilation
Damp-proofing and waterproofing measures
These details are critical because they show how your design meets requirements relating to structure (Part A), fire safety (Part B), energy efficiency (Part L), ventilation (Part F) and other relevant parts of the regulations.
For example, if you are building an extension, building control will want to see how the new walls achieve current thermal standards and how the roof avoids condensation risk. If you’re converting a loft, they will look closely at the new floor structure, stair design and fire protection measures.
The more clearly these details are drawn, the smoother the approval process tends to be.
Structural Drawings and Calculations
If your project involves altering load-bearing elements, you will almost certainly need input from a structural engineer.
This typically applies when:
Removing or altering structural walls
Installing steel beams (RSJs)
Adding significant weight to an existing structure
Undertaking a loft conversion
Building a basement
Structural drawings are accompanied by calculations that demonstrate the proposed design can safely support loads. Building control will assess these to ensure compliance with structural safety standards.
Trying to proceed without proper structural documentation often leads to delays, additional costs and potential safety risks.
Drainage and Services Information
For extensions, basement works or significant internal alterations, drainage drawings are commonly required. These show how foul and surface water will be managed and may include:
Pipe routes and gradients
Inspection chambers
Connections to existing systems
Soakaways or attenuation measures
Poor drainage design can cause long-term issues, so this is an area building control reviews carefully.
Mechanical and electrical layouts are not always required in full detail for domestic projects, but compliance still needs to be demonstrated. This may involve showing ventilation strategies for bathrooms and kitchens, heating layouts, or confirmation that electrical work will be carried out by a certified contractor.
Fire Safety and Means of Escape
Fire safety becomes particularly important in loft conversions, larger refurbishments and projects involving layout changes.
Drawings may need to demonstrate:
Protected escape routes
Fire doors and their ratings
Smoke alarm locations
Fire-resistant construction between floors
Escape window sizes and positions
Even relatively modest changes can trigger additional fire safety requirements, so it’s important that drawings are assessed in the context of the whole house, not just the new work.
Supporting Documentation
Drawings are often supported by written specifications and calculations. These help clarify materials and construction methods where necessary.
A specification might confirm:
Insulation types and thicknesses
Fire ratings of doors and walls
Waterproofing systems
Structural timber grades
Energy calculations, such as U-value assessments, are frequently required for new extensions or alterations to the building envelope. In some cases, more formal energy assessments may be needed.
While this paperwork may feel technical, it plays an important role in demonstrating compliance before work begins.
Full Plans vs Building Notice
When applying for building control approval, you typically choose between a Full Plans submission and a Building Notice.
A Full Plans application involves submitting detailed drawings and receiving formal approval before starting work. This route provides greater certainty and reduces the risk of mid-project surprises.
A Building Notice allows work to begin without prior approval of detailed plans, but compliance is checked during construction. While suitable for smaller projects, it offers less reassurance and can lead to on-site changes if something doesn’t meet regulations.
For most substantial works, investing in a comprehensive drawing package and submitting Full Plans tends to be the more secure option.
What Happens After Submission?
Once submitted, your drawings are reviewed by either the local authority building control department or an approved inspector. They assess the plans against current Building Regulations and may request amendments or further details.
After approval, inspections take place at key stages of the build, such as:
Foundations
Structural installations
Insulation before covering
Final completion
The completed work must match the approved drawings. At the end of the process, a completion certificate is issued. This document is crucial for future property sales and provides confirmation that the work complies with regulations.
Why Getting the Drawings Right Matters
Building regulations drawings are more detailed than planning drawings for a reason. They are about safety, performance and longevity.
Clear, thorough drawings:
Reduce the risk of costly changes during construction
Help contractors price and build accurately
Demonstrate compliance before work begins
Provide reassurance to building control inspector.
Most importantly, they protect you as the homeowner. They ensure that your investment is being built to recognised standards and that hidden elements — structure, insulation, fire protection — are properly considered.
In the end, building control approval isn’t just a box-ticking exercise. It’s a safeguard. The right drawings bring clarity to the process, minimise uncertainty and build trust between you, your designer, your builder and the authorities overseeing the work.
If you approach this stage with the right level of detail and professional input, it becomes a structured and predictable part of your project rather than an obstacle. And that clarity, more than anything, is what keeps a build running smoothly from paper to completion.
Sources
Building Regulation Drawings in London, Extension Architecture, https://extensionarchitecture.co.uk/building-regulations/.
The A-Z of building regulations drawings with building regs checklist, Urbanist Architecture, https://urbanistarchitecture.co.uk/building-regulations-drawings/#:~:text=Your%20building%20regulations%20plans%20should,calculations%2C%20specifications%20and%20construction%20notes.
When Are Building Regulation Drawings Needed in London, Mammoth Design & Build, https://www.mammothbuilds.co.uk/advice/when-are-building-regulation-drawings-needed-in-london.