How far in advance should I book?
Earlier than you think, and the reason is that the fitting itself is the shortest part of the whole sequence. A straightforward roof window is a day outside and a day inside. Everything before that day, the survey, the order, the manufacture, the scaffold and the Building Control notification, runs on other people’s diaries and on materials that come from a factory or a reclamation yard. No honest number of weeks can be published here, because a stock-size unit into a concrete tile roof in Quedgeley and a conservation unit into diminishing courses of Cotswold stone slate in Painswick sit at opposite ends of the same process. What can be set out is exactly what determines the wait, so you can work out where your own job sits. The full installation sequence is on the skylight and rooflight installation page.
What a date actually sits at the end of
A fitting date is the last item on a list, not the first. In order, the list runs like this.
- Photographs and an indicative range by email.
- A survey, on site, with the covering identified and the structure recorded.
- A fixed price, itemised.
- Any consent or structural design the survey identified.
- The unit ordered, and manufactured or picked from stock.
- Scaffold booked, in a separate diary.
- The Building Control notification submitted.
- Materials on site, including any reclaimed covering.
- The fitting itself.
Six of those nine steps involve waiting on somebody else. That is why the answer to how far in advance to book is governed by the longest single item on your particular list rather than by any general rule.
The survey has to happen before anything can be ordered
Nothing is ordered from a photograph. A survey records the rafter or joist centres and depth, the pitch off a digital level, the position of any purlin, binder, strut or collar, what is already routed through the void, the insulation depth and whether there is a ventilation gap above it. Outside, the covering is identified properly, the batten gauge measured and the underlay condition checked.
That takes about forty minutes for a single roof window and longer for a lantern, and it has to be booked into a working week. It is also where surprises appear. Finding a purlin exactly where the room wanted the window, or an existing opening with no trimmer under it, changes the specification and therefore the order. Anyone counting weeks should start counting from the survey rather than from the first email.
Stock sizes against made-to-size units
This is the single biggest fork in the timeline, and it is decided by the roof rather than by preference.
| Unit | Where it comes from | What governs the wait |
|---|---|---|
| Standard manufactured roof window in a common size code | Distributor stock | Usually the shortest route. Common sizes in white polyurethane move fastest |
| Less common size code, or a timber finish | Factory or central stock | Depends on what the maker holds. Some codes are made in batches |
| Flat roof rooflight, made to size | Fabricated to order | Manufacture starts only after the kerb dimensions are confirmed on site |
| Roof lantern | Fabricated to order | Frame made after the kerb is built and measured, so the kerb comes first |
| Conservation rooflight | Specialist maker, smaller ranges | Often a longer lead than a mainstream unit, and finish options add to it |
| Electrically operated or solar unit | Factory build with the actuator fitted | Fewer held in stock than the equivalent manual unit |
| Non-standard glass: solar control, triple, laminated upgrades | Glass plant | Sealed units are made to order, and the glass sets the pace |
The pattern is consistent. Anything made after you order it takes longer than anything sitting on a rack, and the more specific the specification the more likely it is to be made rather than held. That is worth knowing at the point you choose the unit, not afterwards.
Reclaimed stone slate, and the wait nobody controls
On a Cotswold roof this can be the longest item by a wide margin. Forming an opening in diminishing courses means taking the courses back up the slope and re-laying them, and slates come out broken. Replacements have to be reclaimed stone matched for thickness, size and weathering colour, because new stone stands out against a two-hundred-year-old roof for a decade or more.
Yards hold what they hold. A batch of the right size and thickness may be available immediately or may take weeks to appear, and there is no way to accelerate it. The sensible approach on a stone roof is to identify the material requirement at the survey and start looking for it while the rest of the process runs, rather than treating it as a step that begins after the unit arrives. The same applies to handmade clay plain tiles and to matching Welsh slate on an older Cheltenham or Forest terrace.
Scaffold is a second diary you are booking
Most pitched roof work needs a scaffold or a tower, and a scaffold company has its own schedule, its own erection and dismantle visits, and its own weather constraints. On a straightforward semi with a driveway that is a routine booking. On a Stroud valley cottage reached by steps and a shared lane it takes longer to plan and longer to build, because the material is hand-carried in.
The scaffold also has to align with the fitting date at both ends, because a scaffold standing idle for a fortnight is a cost with no work attached. Where several units are going in on one elevation, one scaffold covering all of them is materially better value than three separate visits, and that is worth deciding before anything is booked. Whether a job needs scaffolding at all is answered separately.
Structural work, and the step it adds before a date exists
Where the opening needs more than a head and cill trimmer between two existing rafters, an engineer becomes part of the timeline. Cutting across two or three rafter bays, or carrying a trussed rafter on a beam, needs a calculation, a specified member, and Building Control approval of it before the covering comes off.
That is a normal piece of work and it is regularly the right answer for a loft room. It is simply a different length of process from a narrow unit dropped between two trusses. The survey says which one you are looking at, in writing, which is the point at which a realistic date can be discussed rather than guessed. Trussed roofs are covered on the trussed roof page.
Consent, where a building is listed or in a conservation area
Listed building consent and planning applications have statutory determination periods, and a pre-application conversation with a conservation officer sits in front of them. Neither can be compressed. On a listed roof this is almost always the governing item in the whole programme, and it is the one to start first.
The useful move is to run the consent process and the survey in parallel rather than in sequence, so that the unit specification and the officer’s conditions arrive at the same time. Where a condition requires matched reclaimed covering or an agreed soaker detail, knowing that early feeds straight into the material search. The route is set out on the listed building page.
Season and weather, and what they change
Rooflights go in through the winter and the sequence is built around it: an opening is not started unless it can be closed and made watertight the same day, and if the forecast turns during the morning the outside work stops at a point where the roof is whole. What winter changes is not whether the work happens but how many usable mornings a week there are, and how much slack a programme needs.
Spring and early summer are when most households decide they want more light, which puts pressure on the same weeks that builders, plasterers and scaffold companies are already busiest. Booking a summer job in the winter is a genuinely better position than booking a summer job in June. The reverse is also true: a winter installation often moves faster through the diary. Winter installation is covered in its own answer.
Booking around other trades and other events
A rooflight rarely arrives on its own. It lands in the middle of a loft conversion, a kitchen extension, a rewire or a decorating programme, and the order it happens in matters more than the exact date.
A few sequencing points that recur. The unit goes in before the plasterer, because the reveal is plastered as part of the same operation. Any first-fix wiring for an electric opener or a powered blind has to be in before the plasterboard. On a new extension the kerb has to exist and be measured before a made-to-size unit or a lantern can be manufactured, which puts the roofer ahead of the glazier. And where a house sale is on the horizon, the Building Control completion certificate needs to be in hand before the solicitor asks for it, which pulls the whole programme forward.
What to send now, so a date can exist later
The earliest useful step costs nothing and starts the clock in the right place. Email info@severnskylightsgloucester.co.uk with a photograph of the roof from the garden or the street, a photograph of the room from inside, the covering if you know it, roughly where you want the daylight to land, and the address. An indicative range comes back by email, and with it a view on which of the items above is likely to govern your timeline.
From there it is a survey at a time that suits, a fixed price, and a date. The Building Control notification is handled as part of the job, so that step needs nothing from you beyond the go-ahead. If the answer to a particular question turns out to be a long material lead or a consent application, you will know at the range stage rather than three weeks in.
Next on this subject.
- Question Do rooflights need planning permission? Usually not. Putting a rooflight into the roof of a house is normally permitted development, which means the national rules…
- Question Do I need building regulations approval for a rooflight? Yes. Forming a new opening in a roof is notifiable work under the Building Regulations, and it is notifiable whether…
- Question Who notifies building control about a rooflight? In law the duty sits with the person having the work carried out, which means the homeowner, and in practice…
- Question How much does a rooflight cost? There is no single figure, and any site that publishes one is quoting for a job it has not seen.…