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FENSA gaps: small documents, collapsed sales

· 4 min read · Homeowners

An invoice proves you bought a window. It does not prove the window was installed to Building Regulations. Missing FENSA or CERTASS certificates remain one of the most common reasons a straightforward sale grinds to a halt.

It feels like the least significant thing on a project. New patio doors. Two windows in the kitchen extension. Yet missing glazing documentation is one of the most reliable ways for a property transaction to stall.

Since 2002, replacement glazing has had to comply with thermal and safety requirements under Building Regulations. Compliance is demonstrated either by a certificate from a registered installer — FENSA or CERTASS being the common schemes — or by direct sign-off from Local Authority Building Control.

The invoice problem

Builders often hand over a folder of window product invoices at the end of a job, and homeowners file them as proof. An invoice records a purchase. It says nothing about who installed the units or whether the installation met the regulations.

When the buyer's solicitor cross-references visible window replacements against the local authority register and finds nothing, the transaction stops while it is sorted out.

  • Ordering duplicate certificates, straightforward if the installer was registered
  • An indemnity policy, which buyers' solicitors increasingly push back on
  • Detailed enquiries about safety glass in critical locations — doors, side panels, low-level glazing
  • Buyer fatigue, where a chain of small unanswered queries kills an otherwise good sale

Where we fit — and where we do not

We are not glazing installers or building control surveyors. We do not inspect glazing, assess whether safety glass was correctly specified, or issue any form of certificate. Where that judgement is needed it comes from the installer, the scheme or building control.

Our contribution is a close-out review: going through the job at the end and assembling a dated, organised compliance folder — glazing certificates alongside the electrical, gas, structural and building control paperwork — so it can be handed straight to an insurer, a lender or a buyer's solicitor without anyone hunting through old emails and kitchen drawers.

Worth saying about installers

Registered installers issue these certificates as a matter of routine, and most homeowners who are missing one are missing it because the paperwork went to an email address they no longer use, or the job was done by a previous owner. It is usually recoverable. It is much easier to recover eighteen months before you sell than eighteen days after you accept an offer.

This piece is drawn from reputable published sources — the FENSA and CERTASS scheme guidance, GOV.UK building regulations guidance and standard conveyancing practice — but it has not been individually verified line by line, which is why no company, individual or specific case is named in it. Requirements also change over time. Treat it as a general explainer and confirm the current position with the relevant scheme, your building control body or your solicitor before you act on it.

This article draws on reputable published sources and public enforcement reporting. It has not been fully verified case by case, so no individuals, companies or addresses are identified.

This article is general guidance, not advice about your particular site or premises. If you want it applied to your own job, the first call is free.

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