Building regulations on a supply-only order

Replacing a window or an external door is notifiable work under the Building Regulations. That is true whether a company fits it or you do.

Two routes

Competent person scheme. A FENSA or CERTASS registered installer self-certifies the work and issues a certificate, usually within a few weeks. No council involvement, no separate fee. This is what happens on a supplied-and-fitted job.

Building control. On a supply-only order there is no registered installer, so you notify your local authority building control yourself, pay their fee, and they inspect and issue a completion certificate. Fees vary by council and by how many openings are involved.

What is actually being checked

• Thermal performance. 1.4 W/m²K or better for a replacement window in England, or WER band B.
• Ventilation. Part F — trickle vents where the existing window had them, and in most replacement cases regardless.
• Safety glazing. Toughened or laminated in critical locations — low level, beside doors, in doors.
• Means of escape. Habitable rooms need an escape window of adequate size; do not lose one by changing the opening configuration.

Why it matters later

When you sell, the buyer's solicitor asks for the certificate for any window replaced since April 2002. Not having one means an indemnity policy or a retention, and it is a needless irritation at exactly the wrong moment. Notify at the start; it is administratively dull and permanently fixed.

New windows in a new opening, in an extension, are covered by the building control application for the extension itself — you do not need to notify separately.