This article is written for site teams, supervisors and managers who are dealing directly with the Building Safety Regulator for the first time.

Under the Building Safety Act framework, construction work is no longer judged only on whether it looks correct or performs as expected. It is judged on whether it matches what was approved. Any departure from approved information is treated as a controlled change.

What Is a Controlled Change?

A controlled change is any change to the approved drawings, specifications or strategies submitted to the Building Safety Regulator.

This includes changes to:

• Construction details
• Materials or products
• Layouts or dimensions
• Fire stopping arrangements
• Structural elements
• Service routes and penetrations

If it was shown on an approved drawing or document, it is controlled. Changing it without assessment is not allowed.

Why Controlled Changes Exist

Controlled changes exist to stop safety-critical decisions being made informally on site.

In the past, many changes were resolved through experience, judgement or agreement between contractor and consultant. Under the current regime, those decisions must be visible, recorded and where required, approved.

This is not about slowing construction. It is about preventing unreviewed changes that affect fire safety, structure or escape.

What Site Teams Can Change

Some changes may be classed as minor. These are typically changes that do not affect:

• Fire performance
• Structural integrity
• Layout or means of escape
• Approved strategies

Examples may include:

• Minor dimensional adjustments within tolerance
• Non-safety-critical sequencing changes
• Temporary installation methods that do not alter final outcomes
• Even minor changes still need to be assessed and recorded. Minor does not mean unrecorded.

What Site Teams Cannot Change Freely

Any change affecting safety-critical elements is not freely changeable.

This includes:

• Fire stopping details
• Compartmentation lines
• Structural connections
• Wall, floor or slab build-ups
• Door sets, seals or fire ratings
• Service penetrations through fire-rated elements

These changes are usually notifiable or major and require formal review before work continues. Building first and explaining later is no longer acceptable.

The Common Site Trap: Like-for-Like Substitutions

One of the most common misunderstandings on site is the idea of like-for-like.

A product that looks similar or performs a similar function is not automatically acceptable. Differences in:

• Fire rating
• Certification
• Installation method
• System compatibility

can turn a seemingly simple substitution into a compliance issue.

If a product is named or implied in approved information, changing it must be assessed first.

What Happens If a Change Is Built Without Approval

Unauthorised changes create multiple risks:

• Delay to Gateway 3 approval
• Requirement for opening up or rework
• Additional testing or assessment
• Increased scrutiny from BSR

Even if the change is technically acceptable, the lack of approval and evidence can cause serious delays later.

How Site Teams Should Handle Changes

The safest approach on site is simple:

• Assume the change is controlled
• Pause the affected work
• Raise the issue formally
• Record the decision

Early assessment almost always causes less delay than retrospective justification.

The Key Principle

Controlled changes are not about stopping work. They are about making sure changes are seen, assessed and recorded before they are built. If site teams work on the assumption that any deviation needs checking, controlled changes become manageable rather than disruptive.

 

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Expert Verification & Authorship: Mihai Chelmus Founder, London Construction Magazine | Construction Testing & Investigation Specialist