The short answer
Yes, in nearly every case. Cutting a new opening in a roof is building work, and it is notifiable to Building Control because it changes the structure, the insulation line and the fire and weather protection of the roof. The notification is made before work starts, the work is inspected, and a completion certificate follows. We handle that notification for you.
Why a new opening counts as notifiable work
Every job in our skylight and rooflight installation work starts from one fact: a roof is a structural and thermal element of the house. The moment a rooflight is cut into it, the roof no longer behaves the way it was built to behave, and the Building Regulations want to see that the change has been done properly.
Think about what the saw actually does. A sloping roof is held up by rafters or trusses that carry the load of tiles, felt and snow down to the walls. A flat roof is held up by joists that do the same job. Cut one of those members and the load has to go somewhere else. That means trimming the opening with new timbers or steel, sized for the span and fixed back into the structure that remains. Building Control cares about that because a badly trimmed opening can sag long after the plaster has been painted.
The second concern is heat. Every roof has an insulation layer, and a rooflight punches through it. The glass and frame have to meet the thermal limits in Part L, and the gap between the frame and the roof has to be insulated so that the opening does not become a cold spot above the room.
The third is the roof covering itself. The upstand, the flashing or the membrane upturn all have to be formed so that the roof stays weathertight and the fire performance of the roof surface is not weakened. That is why a new opening is treated as work in its own right, however tidy the finished result looks from inside.
The parts of the regulations a rooflight touches
No single rule covers a rooflight. Several Parts apply at once, and the survey is where we work out which ones bite on your roof.
| Part | What it covers | What it means for your opening |
|---|---|---|
| A | Structure | Trimmers or a lintel to carry the loads around the hole |
| B | Fire safety | Roof surface and distance to the boundary |
| F | Ventilation | Whether the room needs an opening part for air |
| K | Safety glazing | Laminated glass where people could fall onto or through it |
| L | Energy | Thermal performance of the glass, frame and upstand |
Part B is the one homeowners forget. A rooflight made of plastic sheet, or sited close to a boundary, can be limited in size or position because of how fire could spread between buildings. Glass rooflights are generally the simpler route, and we check the distance at the survey.
Part K matters more than it sounds. Glass overhead has to be chosen so that, if it breaks, it does not fall on someone. Laminated glass holds together, which is why it is the sensible inner pane on most of what we fit. It is also the glass that helps most with rain drumming, so the two requirements pull in the same direction. The detail is in our guide to acoustic laminated glass.
Part L sets the thermal bar for new and replacement glazing in a roof. Our page on energy efficient rooflights explains how the glazing build reaches it, and the wider picture is in building regulations for rooflights.
What the notification covers when we handle it
Notifying Building Control is a process with a few clear stages. You do not need to learn the forms, because we run them, but it helps to know what is happening on your behalf.
- Notice before work starts. The building work is notified to the local authority Building Control team, or to a registered private approver, with the drawings and details of the opening and the unit.
- Inspection while the work is open. The inspector looks at the trimming and the insulation before they are covered, because that is the stage where faults are easy to see and easy to put right.
- Final inspection. Once the unit is in and the roof is made good, the inspector checks the finished work against the notice.
- Completion certificate. This is the document you keep. A buyer's solicitor may ask for it when you sell.
The notification is part of the job rather than an add-on, and it sits alongside the written quiet spec that comes with every quote. Where the spec names the glazing build, the notice names the structure and the thermal detail. Between them they describe the opening on paper before anyone climbs the ladder.
Planning permission is a different question
Building Control and planning are two separate systems, and passing one says nothing about the other. Building Control asks whether the work is safe and energy sensible. Planning asks whether it is allowed on that house in that place.
Many rooflights on the rear or side slope fall within permitted development, but the answer changes for some roof slopes facing a highway, for flats, and for conservation areas and listed buildings. We explain that side in planning permission for rooflights and skylights and in the shorter answer on permitted development. Locally, Crawley Borough Council and rooflights covers where the borough council comes in.
A sensible order is to settle planning first, then the specification, then the notification. The survey covers all three, so one visit gives you a clear path. When you are ready, get a quote and tell us about the room.
Related questions on Building Control and rooflights
Does replacing an existing rooflight need notifying too?
Often it does, because a replacement unit must meet current thermal and safety standards. The answer depends on what changes, and we set it out in is replacing a rooflight notifiable.
Will Building Control slow the job down?
The notice is sent before the work, and inspections are booked around the stages of the job, so they fit into the programme rather than stretching it. Timings for the fitting itself are on how long it takes to fit a new rooflight.
Do I need a structural engineer for the opening?
Sometimes. A wide opening, a cut through a truss or a steel beam usually calls for calculations, while a small opening between rafters often does not. See does a rooflight need a structural engineer.
What do I receive when it is finished?
You receive the completion certificate, the written quiet spec and our 10-year workmanship guarantee. Together they are the paper record of the job.