Building Notice vs Full Plans: Which Do You Need?

A Building Notice is a short form (typically 2 pages) that tells building control you are about to start work. You submit the notice, pay the fee, and can start work 48 hours later.

Building control does not check any drawings before you start. Instead, they review the work through site inspections as the build progresses.

When to use a Building Notice

• Straightforward extensions where an experienced builder knows the building regulations requirements
• Simple projects like a garage conversion, internal wall removal, or window replacement
• When speed matters — you can start work almost immediately
• When the builder is confident and has done similar work many times

Risks of a Building Notice

• No approved drawings before you start. If building control finds something non-compliant during an inspection, you may need to redo work.
• Your builder carries more risk. If they get something wrong, it is discovered on site rather than on paper.
• No formal record of what was approved. Unlike Full Plans, there is no stamped set of drawings.

A Full Plans application means you submit detailed architectural and structural drawings before work starts. Building control checks the drawings and issues a formal decision:

• Approve — the design complies
• Approve with conditions — complies subject to certain requirements
• Reject — does not comply (with reasons, so you can amend)

The decision takes up to 5 weeks (or 2 months if you agree to an extension). Once approved, you have a set of stamped drawings that your builder works to.

When to use Full Plans

• Loft conversions — the fire safety, staircase, and structural requirements are complex
• Two-storey extensions — more structural complexity
• Structural alterations — removing loadbearing walls, underpinning
• When you want certainty before committing to a build contract
• When selling soon — Full Plans approval provides better documentation for conveyancing

Advantages of Full Plans

• Certainty before you start. You know the design complies before your builder begins.
• Reduced risk of costly changes. Problems are identified on paper, not on site.
• Formal record. The approved drawings are a permanent record.
• Better for disputes. If something goes wrong, the approved drawings provide clear evidence.

The fees are usually similar for both routes.

If you start with a Building Notice and building control identifies significant issues during construction, they may suggest you submit Full Plans to resolve them. This is uncommon but possible.

You cannot start with Full Plans and then switch to a Building Notice — once Full Plans are submitted, the formal checking process applies.

Both routes are available whether you use your local authority building control (LABC) or a private approved inspector. The process is essentially the same, though private inspectors may offer more flexibility on timing.

Read our comparison of LABC vs private inspectors →

Use a Building Notice if the project is simple, your builder is experienced, and you want to start quickly.

Use Full Plans if the project involves significant structural work, fire safety considerations (loft conversions), or if you want the security of approved drawings before committing to a build.

When in doubt, choose Full Plans. The small time delay is almost always worth the peace of mind.