The Myth: “You must have a FENSA certificate for every double glazing installation.”

It’s one of the most common misconceptions we hear from homeowners in Chichester and across West Sussex — the idea that a FENSA certificate is the only way to prove your new windows and doors comply with Building Regulations.

The truth is a little different… and a lot simpler.

✅ The Truth: FENSA is just one of several Government-approved Competent Person Schemes

FENSA is well known in the glazing world — but it isn’t the only route to compliance.

At Keystone Glazing, we’re proudly CERTASS Registered, which is an equally valid Competent Person Scheme authorised by the Department for Levelling Up, Housing and Communities (DLUHC).

Both FENSA and CERTASS exist for the same reason: to allow trained, vetted installers like us to self-certify that our work meets Building Regulations — instead of having to book a separate Building Control inspection for every job.

🏠 What the Certificate Actually Does

A CERTASS (or FENSA) certificate is effectively the Building Control sign-off for your installation.

It confirms that:

  • Your windows and doors comply fully with current Building Regulations

  • The work was completed by a Competent Person approved under the Government scheme (a.k.a MTC)

  • You’re protected by an insurance-backed guarantee and a recorded compliance certificate

So, while the logo at the top may differ (FENSA, CERTASS, or another approved body), the certificate’s legal purpose is the same — it’s the official building-control approval for your glazing work.

That’s why homeowners selling a property need to show this certificate: it proves the work was signed off under the Competent Person Scheme without needing separate council inspection records.

🗓️ When is a FENSA or CERTASS Certificate Actually Required?

Not every glazing job needs to be registered or certified.
Here’s when you do — and don’t — need a compliance certificate:

✅ Required:

  • Replacement of entire windows or external doors in existing residential properties (not new builds)
    If we remove the old frame and install a new one, it must be certified under a Competent Person Scheme such as CERTASS or FENSA.

  • Doors with more than 50% glazing
    Building Regulations classify these as glazed doors and therefore subject them to energy and safety compliance requirements — so they must be certified too.

🚫 Not Required:

  • New-build properties
    New homes are inspected and signed off by Building Control as part of the construction process, so a separate FENSA or CERTASS certificate is not required.

  • Glass-only replacements (where the frame stays in place)
    If we’re simply replacing a failed or misted glass unit, no Building Control notification is needed.

  • Internal doors or windows
    Only external fittings that affect a property’s thermal performance or safety glazing requirements need certification.

At Keystone Glazing, we’ll always tell you whether your project requires certification before we start — and if it does, we’ll register it automatically through our CERTASS system at no extra cost.

If you live in a Listed building or Conservation area you must still seek guidance from the local authority pertaining to what you are allowed to do on your home – we can support you with this!

🧰 FENSA vs CERTASS: What’s the Difference?

Feature FENSA CERTASS
Government Authorised? ✅ Yes ✅ Yes
Covers Windows & Doors? ✅ ✅
Allows Self-Certification? ✅ ✅
Building Regulation Compliance Certificate? ✅ ✅
Insurance-Backed Guarantee? Optional ✅ Included
Online Certificate Verification? ✅ ✅

Both schemes are recognised and accepted nationwide by solicitors, estate agents, and insurers when confirming Building Regulation compliance.

🪟 Why Keystone Glazing Chooses CERTASS

As a CERTASS Registered Installer, we believe their approach better supports both installers and homeowners:

  • Faster certificate turnaround times

  • Transparent online verification system

  • Inclusive insurance-backed warranties

  • Direct support for local, independent businesses

For you as the customer, that means peace of mind that every installation we complete is fully compliant, legally certified, and professionally guaranteed — all handled automatically through CERTASS.

📄 How to Check or Replace Your Certificate

You can verify your certificate anytime at www.certass.co.uk.
Simply enter your postcode and installation number to confirm your registration.

Lost it? CERTASS can re-issue your certificate, and it remains valid indefinitely as part of your home’s compliance record.

🧭 In Summary

You don’t need a FENSA certificate.

You do need a valid Building Regulation Compliance Certificate.

At Keystone Glazing, we provide that through our CERTASS registration — giving you the same government-recognised Building Control approval, full compliance, and complete peace of mind.

📍 About Keystone Glazing

Based in Chichester, Keystone Glazing is your local expert for windows, doors, conservatories, and double glazing repairs.
We’re a CERTASS Registered Installer and proud members of the Government’s Competent Person Scheme — trusted to self-certify our installations to the highest standards.

📞 Call 01243 302841 to request your free quote today.