Do Skylights Need Building Regulations Approval?

Two different sets of rules

People often mix up planning permission and Building Regulations. Planning is about whether something may be built and how it looks. Building Regulations are about whether it is built safely and to a proper standard. A skylight can be fine on planning and still need Building Regulations approval, and the other way round is also possible.

When approval is needed

Which jobs are notifiable

A new opening in a roof	Yes, checked on both strength and heat loss
Taking out and renewing the whole rooflight	Yes, it is a controlled fitting
Replacing a sealed glass unit alone	No
A new rooflight in a new extension	Covered by the extension's own approval

The reason a new opening is notifiable is plain enough. Cutting through rafters changes how the roof carries its load, and a hole in an insulated roof changes how much heat it loses. Both are matters the regulations exist to check.

What gets checked

Building Control looks at two things in the main. The first is structure: the trimmers framing the opening have to take over the load of every rafter that was cut, and the timber has to be the right size for the span. The second is thermal performance. Under Part L 2021 for existing homes, a roof window needs a U-value of 1.4 W/m²K or a Window Energy Rating of Band B, and a rooflight needs 2.2 W/m²K. The product you choose has to meet those figures.

What does not apply

A couple of requirements are often assumed. There is no Building Regulations daylight requirement for houses, so you will not be told to add a window for light. Nor is there a rule in Part K that dictates the glass type overhead. We choose laminated inner panes ourselves, because it is the sensible option over a room.

A rooflight as a way out of a loft

If a loft conversion is planned, a different rule matters. Approved Document B, on means of escape, accepts a window as the exit only for a storey up to 4.5m off the ground. Convert the loft of a two-storey house and what you need is a protected stair, with a roof window playing no part as the exit. A bungalow or chalet bungalow with rooms under the roof is where a roof window can still do the job, inside that height.

Who arranges it

You can use your local authority Building Control or a registered building control approver. Where your job is notifiable we put the notification in ourselves, so you are not left chasing it. The hidden work, including trimmers, upstands, flashings, membranes and insulation, is photographed as it goes, which makes an inspection easier and gives you a record.

What you receive

Handover is a walk-through of the finished work. With it come the product details, the makers' warranties, our 10-year workmanship guarantee and, for notifiable jobs, the Building Control paperwork. Keep all of it. A buyer's solicitor may ask for it when you sell.

If you skip it

Leaving Building Regulations out is a false saving. The council can ask for work to be opened up for inspection, and an unrecorded roof alteration shows up when a buyer's solicitor asks what has been done to the house. A rooflight with no completion paperwork can hold up a sale, and putting it right afterwards costs more than doing it properly once. That is why the paperwork is part of the handover, not an optional extra.

How long the paperwork takes

The notification itself is usually quick to submit, but the sign-off follows the work, so a certificate arrives after the job is finished and not before it. If the inspector wants to see the framing, the visit is timed before the lining goes up, which is one reason hidden work gets photographed and left open to view until it has been seen. Tell us early if you are about to sell or remortgage, and we will plan the order of work so the inspection falls inside your timetable.

A completion certificate is the document to look for. A building notice or application on its own shows only that someone began the process, and solicitors tend to ask for the certificate.

Different councils, same rules

The regulations themselves are national, so the technical standards do not change from York to Harrogate or Selby. What differs is who you deal with. Each authority around York, whether City of York Council, Leeds, Wakefield, Doncaster or the councils of North Yorkshire and the East Riding, runs its own building control team, and a registered building control approver is the alternative for any of them.

Where planning fits in

Most rooflights on houses are permitted development, though conditions apply, and flats and listed buildings are different. The page on skylight planning permission and Building Regulations sets out the detail. For related questions, see replacing an old skylight, and for the whole service start at the Prestige Skylights York home page.