About Severn Skylights

What fifteen years in one trade actually buys

Anybody can learn to fit a manufactured roof window in a concrete interlocking tile roof. The kit comes with instructions, the tiles unclip, and the flashing is designed to be difficult to get wrong. That job is a small part of what arrives in the inbox.

The time goes into the other roofs. Knowing before the ladder goes up that a Painswick roof in diminishing courses cannot have an opening cut into it and closed around a frame. Knowing that the shallow upper slope of a Cheltenham mansard sits below the pitch a roof window is rated for, so the answer is a kerb-mounted unit and not the one in the brochure. Knowing that a rear addition in a Gloucester terrace usually offers about two metres of slope, and that the size somebody has already chosen will not lap into it. Fifteen years is mostly a catalogue of roofs that behaved differently from how they looked from the pavement.

It also buys the habit of saying so early. A survey that ends with a smaller unit than the customer imagined, and the reason set out in millimetres, is a better outcome than a large one fitted with a head flashing that has nothing to lap under.

Why the perimeter gets discussed before the glass

Most enquiries begin with a product: a size, a brand, a picture of a kitchen. That is a reasonable place for a homeowner to start and it is the wrong place for an installer to start, because the unit is the small half of the job.

What decides whether an installation is dry in twenty years is the perimeter. Upstand height measured from the finished surface of the waterproofing at the high point of the fall rather than from the deck. Falls, so water leaves the roof rather than standing against a kerb for six months a year. Flashing laps run in the direction of flow, and lead fixed at the head only so it can move without tearing. And the point where the roof covering terminates, with the underlay dressed up and around the frame instead of slit and tucked.

Four details, none of them visible once the job is finished, all of them cheap to skip. That is exactly why they get skipped by people working to a day rate, and it is why the workmanship here carries a ten-year guarantee: the guarantee is written against the four things the workmanship controls.

What a survey records, and why it takes as long as it does

A survey is not a sales visit with a tape measure. Inside, the rafter or joist centres and their depth are recorded, the pitch is taken off a digital level, and the position of any purlin, binder, strut or collar is noted along with anything already routed through the void: a tank, a soil pipe, cabling, a flue. Insulation depth and type go down, and whether a ventilation gap survives above it.

Outside, the covering is identified properly rather than generically. Welsh slate at a stated size with a measured headlap is a different job from a handmade clay plain tile, which is different again from stone slate in diminishing courses. Batten gauge is measured. The underlay is checked at the eaves and around any existing opening, because brittle 1930s bitumen felt behaves nothing like a modern breather membrane.

Then the unglamorous half: where scaffold can stand, whether a lorry can turn in the lane, how far glass has to be carried, and how far the internal finish is being taken. All of it moves the price, which is the reason the price comes afterwards.

Two figures, and the reason there is never only one

Work is quoted in two stages, deliberately.

The first is an indicative range by email, worked out from photographs of the roof and the room, the covering, a rough size and the address. It costs nothing and it exists so that nobody spends an afternoon on a survey for a project that was never going to work financially. It is a range because it has to be: nobody has stood on the roof yet.

The second is a fixed price after the survey, itemised so it is clear what is unit, what is labour, what is scaffold and what is Building Control. That figure holds. It moves only if the customer changes the scope, or if something structural is uncovered that was written into the survey notes as a risk beforehand. The costs page sets out what drives a figure up or down.

Why the roof is closed every evening

The roof is never left open overnight. That single rule governs how a job is sequenced rather than the other way round. An opening is not started unless it can be formed, filled and made watertight the same day. If the forecast turns during the morning, the outside work stops at a point where the roof is whole rather than at the point the programme would prefer. Where several units are going in, the sequence runs from the top of the slope downwards so each evening ends with a closed covering.

Homeowners along the Severn and the Avon have watched water get into their houses, and scepticism about anyone cheerful about cutting a hole in a roof is entirely reasonable. The answer to it is the perimeter detailing above and a working day arranged around a closed roof.

The units fitted, and the order the choice happens in

Manufactured roof windows from VELUX, Fakro, Keylite and Roto are fitted, along with made-to-size flat roof rooflights, roof lanterns, conservation rooflights, walk-on units and sun tunnels. Those are products, not affiliations. The size codes and flashing kits are simply the vocabulary a survey gets translated into when an order is placed.

The order of the decision matters more than the brand. The roof decides the family of unit: in-plane roof window, kerb-mounted rooflight, lantern or conservation unit. The room decides the size and the position within what the roof allows. The orientation decides the glass, because a west-facing loft with an overhead unit and no solar control coating becomes unusable in July. Only then does the manufacturer come into it, and by that point the field is usually narrow because one or two of them make the size that fits.

What roofs in this county ask of an installer

Gloucestershire has an unusually wide spread of roof types inside a thirty mile radius, and it is the roof rather than the address that sets the job.

Cotswold stone slate through Painswick, Bibury, Northleach and Chipping Campden is laid in diminishing courses on riven battens, commonly with a lime mortar torching underneath and often no underlay at all. Courses are taken back up the slope and re-laid, with reclaimed slate matched for thickness and weathering colour. Conservation rooflights exist because a standard frame and flashing kit are made for a covering a fraction of that thickness.

Regency Cheltenham is stucco, Welsh slate and mansards, much of it listed, with shallow upper slopes hidden behind parapets. Gloucester’s Victorian terraces and the vale villages are red brick with clay tile over narrow rear additions at low pitches. The Forest of Dean is sandstone and small-format slate on steeper, wetter roofs where laps get taken beyond the manufacturer’s minimum. The interwar semis at Longlevens, Hucclecote and Warden Hill are hipped, so the usable rectangle is far smaller than the roof looks. The trussed estates at Quedgeley, Ashchurch and Yate need a designed trimmer for anything wider than a bay. The Stroud valleys are simply harder to reach, and that is priced honestly rather than discovered on the day.

Town by town coverage is on the areas pages, and the technical detail behind each covering is on the guides.

Building Control, handled inside the job

A new opening in a roof is notifiable work, and so is a replacement in most circumstances. The notification is submitted as part of the job, the inspections are booked, and the completion certificate comes back in the homeowner’s name. Where trimming a rafter or carrying a truss on a beam calls for an engineer’s calculation, that goes in with the application rather than being resolved on the scaffold.

It is worth keeping the certificate somewhere findable. It is the document a buyer’s solicitor asks for, and its absence is a much more expensive problem at the point of sale than at the point of installation.

The ten-year guarantee, and what sits behind it

The workmanship carries a ten-year guarantee. The glass and the frame carry the manufacturer’s own warranty, which is a separate document with its own terms, and the survey notes explain which covers what.

The guarantee is meaningful because of what it is written against. Upstand, falls, flashing laps and the termination of the covering are the four things nobody can inspect once the plaster is on, and they are the four things that decide whether a mark ever appears on a ceiling. Guaranteeing them for ten years is a statement about how they are built, not a marketing device. More on the terms is on the guarantee page.

How to start

Email info@severnskylightsgloucester.co.uk, or use the form on the contact page. Four things make a first reply genuinely useful: a photograph of the roof from the garden or the street, a photograph of the room from inside, what the covering is if you know it, and roughly where you would like the daylight to land. An address helps, because in this county the covering and the conservation status are often obvious from a postcode.

From there it is the range by email, then a survey at a time that suits, then the fixed price and a date. What to send in the first message is set out in more detail on the quote page.