Building Regulations Notes for Extensions: What to Include (Plus Template)

If you regularly submit domestic extensions to Building Control, you’ll know the drawings are only part of the picture. The accompanying notes — those pages of written guidance covering everything from Part L compliance to drainage — play an important role in supporting the submission. But putting them together from scratch each time can be a time-consuming process.

This article is intended as a practical guide to what a set of Building Regulations notes for domestic extensions should typically include, along with some things worth watching out for and how a structured template can help streamline the process.

What Are Building Regulations Drawing Notes?

They’re the written statements that sit alongside your technical drawings in a Building Regulations submission. Their purpose is to clarify things the drawings can’t easily show — responsibilities, standards, compliance routes, construction specifications.

For domestic extensions, alterations and conversions, they’ll typically address:

• The approval route and statutory context
• Planning references and relevant conditions
• Construction standards and material specs
• Structural coordination
• Thermal performance (Part L)
• Fire safety and means of escape
• Drainage and services
• Contractor and client responsibilities

They form part of the formal package going to Building Control, so it’s worth making sure they’re consistent with everything else in the submission.

What Should the Notes Typically Cover?

The exact content will vary from project to project, but here’s a general breakdown of the main sections and what might sit within each.

Statutory Context

This section sets out the regulatory framework around the project. It would normally confirm the Building Regulations approval route, reference any planning consent and relevant conditions, note Party Wall matters where applicable, and acknowledge the Building Safety Act 2022 and CDM 2015 responsibilities.

Having this clearly stated at the outset helps set expectations and can reduce the likelihood of queries further down the line.

Materials and Workmanship

A relatively short section, but an important one. It confirms compliance with Regulation 7 and references the relevant British Standards — for concrete, timber, general workmanship and so on. The aim is to establish that materials and construction methods will meet statutory performance requirements.

Thermal Performance and Part L

This tends to be an area Building Control will look at closely, particularly on extensions and conversions.

It’s worth covering target U-values, how new and retained thermal elements are being treated, glazing area limits (including the 25% rule), thermal bridging strategy, airtightness and condensation risk. Keeping this section aligned with your build-up details and any SAP calculations helps everything read as a coherent package.

Structural Coordination

The structural design itself will normally come from an engineer, but the notes can usefully clarify the division of responsibility — who is responsible for the structural design, what the expectations are around temporary stability during construction, and how the architectural and structural drawings relate to each other.

This kind of clarity can help avoid misunderstandings once the project reaches site.

Fire Safety and Means of Escape

This is particularly relevant for loft conversions, but worth considering on any extension that affects escape routes or fire compartmentation. Notes here might cover fire detection provisions, protected escape routes, fire resistance ratings and stair/guarding compliance, supporting Approved Documents B and K.

Drainage and Services

Foul and surface water drainage, sewer connections, ventilation, electrical compliance under Part P — these all benefit from being referenced in the notes as well as shown on the drawings, so that the submission reads consistently throughout.

How a Template Can Help

Rather than starting from a blank page each time, having a structured base document can provide a reliable starting point. The idea isn’t to remove the need for professional judgement — each project still needs its own review — but to reduce the amount of repetitive drafting involved and help maintain consistency across submissions.

In practice, this tends to mean faster turnaround, fewer things slipping through the gaps, and a more consistent standard across the practice.

About the Template

We’ve put together a comprehensive, editable set of Building Regulations drawing notes aimed specifically at UK domestic projects. It’s supplied as a Word document in two versions:

• Extensions & Alterations — roughly 80 pages
• Extensions, Alterations & Conversions — roughly 137 pages

The notes cover statutory context, construction standards, thermal performance, structural coordination, drainage, fire safety and services. They’re designed as a starting point — something to review, edit and adapt for each project rather than use verbatim.

The template is suitable for domestic extensions, loft conversions, garage conversions and internal alterations. It’s not intended for standalone new-build dwellings, basements or non-domestic work.

It’s supplied as-is, without ongoing updates. Users remain responsible for ensuring compliance with whichever version of the Building Regulations is in force at the time of submission.

Building Your Own Office Standard

Many practices find it helpful to take the template and use it as the foundation for their own internal standard. By tailoring it to your typical construction types and reviewing it when the regulations change, it can become a consistent reference point that the whole team can work from.

Over time, this kind of approach can make a real difference to both efficiency and consistency.

Where to Get It

The full Building Regulations Notes Template is available via our store:

Final Thoughts

Building Regulations notes are an important part of the formal documentation that supports a submission. Getting them right helps demonstrate compliance, supports coordination and can make the Building Control process smoother for everyone involved.

If you’re finding yourself drafting similar notes from scratch for each project, a well-structured template might be a useful way to save time while keeping the quality consistent.