Is Replacing a Rooflight Notifiable?

What "notifiable" means

Certain building work in England has to be told to Building Control before or as it happens, so that someone independent can check it meets the Building Regulations. That is what notifiable means. It is separate from planning permission, and it applies whether or not planning is needed.

Fitting windows and rooflights is covered because the glazing affects heat loss and, in a roof, the structure around it. Swapping the entire rooflight counts as a controlled fitting.

A whole new rooflight: yes

When the frame and the glass both come out and a new rooflight takes their place, Building Control has to be told. Part L of the regulations sets the thermal standard for existing homes. A new rooflight has to reach 2.2 W/m²K. A roof window has a tighter target of 1.4 W/m²K, or alternatively a rating in Band B.

The work is usually checked in one of two ways. The council's Building Control team can receive the notification, or a private firm, called a registered building control approver, can do it. On notifiable jobs we make the arrangements, and the completion paperwork joins the other documents you receive at handover.

A new sealed unit alone: no

If the frame stays and only the sealed glass unit is lifted out and replaced, the work is not notifiable. The frame is not being changed, so it is treated as a glazing change rather than a new fitting. That is one reason a new unit is a lighter job than a whole new rooflight.

Even so, a better unit is a good idea. A new unit usually has a better edge spacer and better coatings than the glass it replaces, and we say what the new specification is on the written quote.

A new opening: always

If the work makes a new opening in the roof, or enlarges an existing one, it needs Building Regulations approval, because the structure has to be altered to carry the loads round the hole. That applies to a new rooflight in a place where there was none, and to a lantern that is larger than the opening it replaces.

Putting a rooflight of the same size into the same opening is simpler, but a whole rooflight is notifiable all the same.

What about planning permission?

Swapping a rooflight like for like rarely raises a planning question on a house. Where it can matter is on a listed building, in a flat or maisonette, or on a street where an Article 4 direction removes permitted development. The council can confirm for your address. The conditions are laid out in the planning permission guide.

How to tell which route you are on

• Is the frame being taken away, or does it stay in place?
• Is the opening the same size, or bigger?
• Is the rooflight being swapped for a different type, such as a dome for a glass unit?

If the frame goes, the opening changes or the type changes, assume Building Control is involved. Our page on whether skylights need Building Regulations goes further into this.

How we handle it

When we visit, we examine the frame and the glass and say which route the job is on. When it is notifiable, the notification, the inspection visits and the completion certificate are arranged for you. You do not chase anyone. The certificate comes to you with the product details and warranties at the end of the job, which matters if you sell the house and a buyer's solicitor asks.

The wider job is described on our misted and failed rooflights page.

Why it matters later

A completion certificate is the record that the work met the regulations. A buyer's solicitor may ask for it when you sell, and without one you can be left chasing the council for retrospective confirmation, which is slower and less certain than having it done at the time.

A glazing change that is exempt, such as a sealed unit in an unchanged frame, leaves no certificate, but the product details and the maker's warranty still matter. Keep them with your house papers.

Who inspects the work

For a notifiable job, a Building Control surveyor may visit before the roof is closed up, to look at the opening and the structure round it. That is one reason the hidden work is done carefully and photographed. Trimmers, upstands, insulation and flashings go out of sight quickly, and good photographs show what is behind the finish.

Common mix-ups

Two points cause most confusion. The first is that people assume a like-for-like swap needs no paperwork. The test is what goes in the bin: if the frame goes, so does the exemption. The second is that people think a new unit means a new rooflight. A unit is the sealed glass sandwich, and the rooflight is the frame that holds it. The regulations treat them differently.

If a quote you have been given does not say which one is being replaced, ask. The answer affects the paperwork, the price and how long the roof is open.

Questions to put to your installer

Before you book, ask whether the quote is for a whole rooflight or a glass unit only, who will submit the notification, and whether the completion certificate is included. Those three answers settle the paperwork and show whether the job has been understood. Keep the written answers with the quote.

If the rooflight sits in a bathroom or over a stair, mention it at the survey, because the glass specification and the way the opening is trimmed may differ there.