Building Regulations for Extensions: What's Involved

The inspection stages and technical areas that shape an extension programme and its cost.

Extensions are assessed under building regulations regardless of whether planning permission is required. It is a staged process with inspections at defined points.

Understanding those stages helps you read a build programme and spot a quote that has skipped something important.

The technical areas assessed

Building control will look at, among others:

The inspection stages

Typically: excavation before concrete, foundations, damp-proof course and oversite, drainage before covering, structural elements, insulation before closing up, and a final completion inspection. Each stage has to be booked, and skipped stages cause delays later.

Keep the paperwork

The completion certificate, electrical certification and any structural calculations are what a future buyer's solicitor will ask for. Store them with your deeds.

Discuss your extension

We'll be straight with you about scope, sequence and what the regulations require.

Frequently asked questions

Is planning permission separate?

Yes, entirely. Some extensions are permitted development and still require full building regulations approval.

Who notifies building control?

Normally the contractor or your appointed agent, but confirm in writing who is responsible before work starts.

Do you do the full build?

We carry out extension work and are also frequently engaged for the glazing package on someone else's build. Either is fine — tell us which you need.

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