Roof Lantern Installation
Flat-roof glazing sized to the room and detailed into the kerb below it.
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Hertfordshire
Rooflight installation in Bishops Stortford
Market town over the county line. What that means for getting glass into a roof here is the whole of this page.
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In Bishops Stortford
What we install on Bishops Stortford roofs
Flat Roof Rooflight Installation
Flush and kerb-mounted units into single-ply, felt and GRP flat roofs.
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Roof windows trimmed into slate, clay and concrete tile without proud flashing.
View this service →VELUX Window Installation
We install VELUX alongside Fakro, Keylite and Roto roof windows.
View this service →Electric and Opening Rooflights
Actuated opening units, rain sensors and controls, wired and commissioned.
View this service →Energy Efficient Rooflights
Specified on U-value and g-value, not on the brochure photograph.
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The local detail
16 things worth knowing about Bishops Stortford roofs
The first thing a Bishops Stortford enquiry settles is which county it is in. The town is Hertfordshire, a short distance west of the Essex boundary, so the planning position and the Building Regulations notification both go through East Herts rather than through any Essex authority. Sunspire works out from Chelmsford, roughly twenty two miles by road, and the town sits inside the area covered from there.
The rest is the town as a roof job sees it. A centre sitting in the bottom of the Stort valley with streets climbing out of it on both sides. An airport a few miles to the north east. A conservation area across the old core, terraced streets built when the railway arrived, and a wide ring of newer estates south and west of the town where the roofs are trussed and the work runs quickly.
- 01 Hertfordshire, not Essex, and what that changes
- 02 The airport a few miles north, and the one order it changes
- 03 A town built across a valley, and where a scaffold stands
- 04 Windhill, the Causeway and the conservation boundary
- 05 Three storey town houses, and how a unit reaches the roof
- 06 Hockerill, Havers Lane and the streets the railway built
- 07 Coverings across the town, and the kit each one takes
- 08 Thorley, Bishop’s Park and the conditions written into them
- 09 Bay width between trusses on a newer Stortford roof
- 10 Rear additions with flat roofs, and what the deck is made of
- 11 Kerb height on an open Stort valley plot
- 12 Which way a Bishops Stortford slope faces
- 13 Turning a Stortford loft into a bedroom
- 14 Hard water, and what it leaves on the outside of the glass
- 15 Building Control on a Hertfordshire address
- 16 Getting a Bishops Stortford roof surveyed and priced
Hertfordshire, not Essex, and what that changes
Nothing about the glass changes at the county line. Everything about the paperwork does. East Herts District Council is the planning authority, its own validation requirements apply to an application, and any local direction that has removed permitted development rights is a Hertfordshire direction rather than an Essex one.
That matters because owners frequently compare notes with friends a few miles east and get a misleading answer. A rooflight that needed no application on a comparable house near Great Dunmow can need one here, and the reverse happens just as often. The position for a specific address is established before anything is measured, and it takes a short conversation with the district rather than a guess from the pavement.
The airport a few miles north, and the one order it changes
Stansted sits to the north east of the town and departure and approach tracks pass over parts of Bishops Stortford depending on which way the runway is being used. Glass in a roof is the thinnest element in the whole building envelope and it faces the sky, which is the direction the sound arrives from.
The practical answer is a specification decision made at order rather than anything structural. A laminated outer pane with an acoustic interlayer damps the frequencies that a plain monolithic pane transmits, and panes of differing thickness in the same unit break up the resonance instead of reinforcing it. The subject is covered properly on the Stansted Mountfitchet page, which sits closer to the runway and goes into the numbers.
A town built across a valley, and where a scaffold stands
The Stort runs through the middle and the ground rises on both sides, sharply on the Windhill side and more gently towards Hockerill and Thorley. Very few plots in the older parts of town are level.
The consequence is a scaffold that has to be built on a slope, with the base plates stepped and the standards founded on properly spread sole boards rather than dropped onto a soft border. Ground near the river is alluvial and softer than it looks after a wet week, and a tower that settles two centimetres during the day is a tower that is out of level when the unit is being set. Working out where the platform stands is part of the survey, not an afterthought on the morning.
Windhill, the Causeway and the conservation boundary
The designation covers the historic centre, running up Windhill and along the High Street and North Street, taking in the Causeway and Water Lane, with the castle mound and the churchyard inside it. Plenty of houses that feel entirely ordinary sit within the boundary.
Inside it, the usual expectation is that a rooflight sits flush in the plane of the covering and reads as a historically plausible opening. In practice that means a conservation pattern unit, a slim black cast frame with a central glazing bar, rather than a modern surround standing proud of the tiles. Those units are made to order, so the sequence is consent first and order second.
Three storey town houses, and how a unit reaches the roof
The hill streets carry a lot of tall, narrow property: three storeys with a stair that turns twice, occasionally more, and rooms stacked rather than spread.
A large sealed unit does not go up through that. It is heavy, it is rigid, and the winder at the half landing decides the argument long before the doorway does. On these houses everything travels externally, up a scaffold or by a mechanical hoist onto the platform, which is one of the reasons access shows up in a price on a town centre address and barely registers on an estate house with a driveway. Working this out early also settles the maximum unit size honestly, because a piece of glass that cannot reach the roof is not an option whatever the drawing says.
Hockerill, Havers Lane and the streets the railway built
The line reached the town in the mid nineteenth century and the terraced and semi-detached streets followed, running out towards Hockerill, along the Havers Lane side and up the London Road approaches. These are cut roofs: rafters, purlins and struts, timber that can be trimmed.
That is good news for anyone wanting a decent sized opening. A cut roof allows rafters either side of the opening to be doubled, trimmers to be fitted above and below, and the load to be redistributed properly, which is routine carpentry rather than an engineering exercise. Pitches through these streets sit around the low to mid thirties, comfortably inside the range every roof window manufacturer will warrant.
Coverings across the town, and the kit each one takes
The flashing kit is chosen by what is actually on the roof, measured on the day, not by what came off the last job. Four coverings turn up repeatedly in Bishops Stortford and each behaves differently at an opening.
| Covering | Where it turns up | What the perimeter needs |
|---|---|---|
| Handmade clay plain tile | The old core and the oldest cottages | Soakers dressed between courses, salvage held ready |
| Welsh slate | Victorian and Edwardian streets | Low profile kit, dressed tight, copper nails on re-lay |
| Concrete interlocking tile | Post-war and later estates | Deep profile kit so the apron does not bridge the troughs |
| Single ply, felt or GRP | Flat rear additions everywhere | Membrane dressed up the kerb and terminated under the unit |
Thorley, Bishop’s Park and the conditions written into them
The southern and western expansion of the town is large and it is recent. Thorley Park, Bishop’s Park, St Michael’s Mead and the phases beyond them are estate housing built from the nineteen seventies onward, and they are where a good proportion of local enquiries come from.
Two things are worth checking before a design is fixed. Permitted development rights on newer estates are frequently restricted by a planning condition attached to the original consent, which is a separate matter from any conservation designation. And the title on a modern plot may carry covenants and a management company with a say over external alteration. Both are quick to establish and slow to unpick if they surface after an order has gone in.
Bay width between trusses on a newer Stortford roof
Anything on those estates is almost certainly a trussed rafter roof. A truss is an engineered component with its webs and bottom chord carrying load in tension and compression, and a web cannot be cut the way a rafter can.
With trusses at six hundred millimetre centres, the clear bay between them takes a unit of roughly five hundred and fifty millimetres in width. That is the honest cap unless a structural engineer designs a trimming solution, which is possible and which brings a calculation, a longer lead time and a different conversation with Building Control. Two narrower units in adjacent bays gives the same glass area, spreads the light more evenly across the ceiling and often looks better than the single wide unit somebody had in mind.
Rear additions with flat roofs, and what the deck is made of
Nearly every Bishops Stortford plot with any depth has gained a single storey rear addition at some point, and the roof over it is flat. That is where most of the glass in the town actually ends up, either a roof lantern where the room is wide enough to carry a raised structure, or a flush unit where the intent is that the roof disappears.
What the survey opens up first is the deck. A chipboard deck under a covering that has been laid over twice will not carry a kerb, and neither will a thin plywood deck that has been damp for a decade. The fall matters just as much. A minimum of 1:80 is what a flat roof is designed to, allowing for deflection and construction tolerance, and plenty of older decks never delivered it.
Kerb height on an open Stort valley plot
One hundred and fifty millimetres from the finished roof surface to the top of the kerb is the figure quoted across the industry. It comes from the depth of water that can lie on a flat roof combined with how far up a vertical face wind driven rain can be pushed.
On a sheltered town centre plot with a good fall, some manufacturers will warrant less. On the open ground west of the town and on the higher plots either side of the valley, where the wind funnels along the Stort with nothing much in front of it, that figure is a floor rather than a target. Reducing it so a lantern sits a little lower is invisible once the job is finished, and it is the decision most likely to be regretted.
Which way a Bishops Stortford slope faces
Orientation is settled before size is. A north facing plane gives even, cool light all day with almost no heat gain and will take a generous area of fairly neutral glass. A south or south west plane collects the July sun at a high angle straight onto the glazing.
Two numbers describe the behaviour and they pull against each other. The U-value measures heat loss and lower is better. The g-value measures how much solar energy gets through, and lower means less gain and slightly less light. Optimise one and ignore the other and you get a room that is cheap to heat in February and unusable at three in the afternoon in August. On a south facing Stortford roof, solar control glass is the default rather than an extra.
Turning a Stortford loft into a bedroom
Loft conversions are common in the town, particularly on the Victorian streets where the footprint is small and the only direction left is up. The pitch on those roofs is usually generous enough, and the limit is the collar, the horizontal timber tying the rafters partway up, which sets the ceiling height across the middle of the room.
Once a loft becomes a habitable room the Regulations engage in a way they do not for storage. A roof window serving as a means of escape has to give a defined clear opening area and a bottom edge within a set height range above the floor, and a centre pivot unit that is fine as a daylight opening will not always satisfy it. That is a decision at specification, not at fitting.
Hard water, and what it leaves on the outside of the glass
Hertfordshire sits on chalk and the mains supply is hard. It shows up on a rooflight in a way it does not on a vertical window, because a horizontal or shallow pitched pane holds the water rather than shedding it.
Wash a rooflight down with a hose on a bright day and the water evaporates in place, leaving mineral deposits that build into a haze over a few years. Self cleaning coatings reduce the frequency of washing rather than removing the need for it, and they behave best where rainwater does the work. The useful habit on a flat rooflight is clearing leaves and grit from around the kerb each autumn, because most water problems around glass in a roof begin as a drainage path that quietly closed itself.
Building Control on a Hertfordshire address
Fitting a new rooflight or replacing an existing one is notifiable work under the Building Regulations in England. It engages Part L for thermal performance, Part K where there is a risk of falling, and Part B where the opening serves as a means of escape from a room in the roof.
Sunspire handles the notification as part of the job, and on a Bishops Stortford address it goes to the Hertfordshire side rather than to an Essex authority. That matters more than it sounds. An unnotified alteration surfaces years later during a sale, when a buyer’s solicitor asks for a completion certificate that was never applied for and there is no quick way to produce one.
Getting a Bishops Stortford roof surveyed and priced
The order of work is consent position, then survey, then order. The survey settles six things: what the covering is and whether salvage is needed, the pitch measured rather than estimated, what is holding the roof up, where the internal ceiling line will land, which designations apply to the address, and how material gets up and waste comes down on that particular street.
Sunspire quotes in two stages, a range by email once the basics are known and a fixed written figure after the survey. For the first, a photograph of the roof from outside, one of the ceiling from inside and a rough room size is enough, and the general ground on what drives the price is set out separately. The workmanship carries a ten year guarantee, which is the honest way to price four details nobody can see once the job is finished.
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