ProLast reviewed 3 June 2026 · 4 min read

What goes on a chimney sweep certificate

A chimney sweep certificate is an evidence-grade record, not a statutory document. This article explains the fields, the role of HETAS / NACS / the Guild of Master Chimney Sweeps, the safety boundary, and what insurers and landlords actually look for.

Important context

A chimney sweep certificate has no single mandated, copyrighted layout in UK law. The major trade bodies (HETAS, NACS, the Guild of Master Chimney Sweeps) each have their own format; the content is broadly consistent across all of them.

Warning: This article is general guidance. The operative reference is the trade body whose membership you hold (HETAS, NACS, the Guild) and, where building work has been done, the relevant Building Regulations approved documents. Speak to your trade body or a qualified consultant for advice on your own circumstances.

What the cert actually evidences

A sweep certificate evidences:

That a sweep was carried out on the named property on the named date
Which flue(s) were swept, by which method, on which appliance
The result of the smoke-evacuation test on each flue
Defects observed and recommendations made
The sweep's finding on whether the appliance is safe to use
That a registered, named sweep stood behind the work

It does NOT certify the chimney as safe in the way a CP12 certifies a gas appliance. There is no statutory instrument in the UK that gives a sweep cert that kind of force. It is evidence-grade, not statute-grade.

The "we never adjudicate safety" boundary

TradeBooked records what you observe and what you decide. It does not compute a pass-or-fail safety verdict from the inputs. You enter "safe to use: yes/no"; the platform stores the answer faithfully, generates the PDF, and emails it. The judgement is the registered sweep's, not the platform's.

This is the same principle as on the Gas Safety Record (CP12). The platform never adjudicates safety, on any cert type.

HETAS, NACS, the Guild

The three recognised UK trade bodies for chimney sweeps are HETAS (Heating Equipment Testing and Approvals Scheme), NACS (National Association of Chimney Sweeps) and the Guild of Master Chimney Sweeps. All three:

Register and audit sweeps
Set conduct and competence standards
Are widely accepted by insurers and landlords as proof of competence

TradeBooked is body-agnostic. You display whichever membership you hold (via the Compliance and credentials section in Settings), and your registration number appears on the issued cert. Customers and insurers look for any one of the three; you do not need to hold all of them.

Building Regulations context (informational)

Building Regulations Approved Document J (combustion appliances and fuel storage systems) covers the installation of solid-fuel and other combustion appliances. It is the operative reference for an installer, not for a sweep doing routine sweeping.

Where a sweep observes that an installation appears to depart from Part J (e.g. obvious flue or ventilation issues), recording that as a recommendation on the cert is the right move. The cert is then evidence; remediation is the customer's decision in consultation with a qualified installer.

Fields on the cert (the inventory)

A complete sweep cert holds:

Property address, customer name, date swept
Per flue: location, appliance type, fuel, usage, construction, liner, sweep method
Smoke-evacuation test result, CO alarm presence/test, nest or blockage findings
Defects (structured codes plus free text), recommendations
Safe-to-use finding (the sweep's call)
Next sweep due (fuel-aware default, editable)
Sweep name, trade-body registration number, signature, cert number (CSW-000123)

TradeBooked's issued PDF carries each of these. Customers and insurers reading the cert see a familiar shape.

Setup steps are in your dashboard

This is a Pro feature. Sign in on a Pro plan to see the step-by-step setup for your number.

Common questions

Is a sweep certificate a legal document?

It is an evidence-grade document, not a statute-grade one. There is no UK statutory instrument behind a sweep cert in the way the Gas Safety Regulations 1998 sit behind a CP12. Insurers and landlords still ask for it as proof of sweeping.

Which trade body should I be a member of?

Pick the one whose standards and audit you are happy to be held to. HETAS, NACS and the Guild of Master Chimney Sweeps are all widely accepted. You only need one membership; display it on your booking page and on the issued cert.

What if I am not sure the appliance is safe to use?

Record that on the cert. Use the recommendations field, set safe-to-use to no, and follow up with the customer or a qualified installer. The cert is a faithful record of what you found; it is not a pass-fail you have to commit to from incomplete information.

Do I have to issue a cert for every sweep?

Not legally. In practice, yes: insurers and landlords look for one and your time-cost of issuing on TradeBooked is small. The cert is also what feeds the rebook and the flue register, so skipping it forfeits both.

What plan do I need?

The sweep certificate engine is on the Pro and Autopilot plans, gated to the chimney-sweep trade type.

References

This is general guidance, not legal, tax or financial advice. For your own circumstances, speak to a qualified professional.

Still stuck? Email support@tradebooked.co.uk.