Roof Lantern Installation
Flat-roof glazing sized to the room and detailed into the kerb below it.
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South Essex
Rooflight installation in Canvey Island
Reclaimed land, bungalows, flood context. What that means for getting glass into a roof here is the whole of this page.
We travel to Canvey Island
10-year guarantee
Canvey IslandTown covered
South EssexWithin
30Mile radius by road
10Year workmanship guarantee
In Canvey Island
What we install on Canvey Island roofs
Flat Roof Rooflight Installation
Flush and kerb-mounted units into single-ply, felt and GRP flat roofs.
View this service →Roof Window Installation
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 Canvey Island roofs
Canvey Island is reclaimed marsh. Dutch engineers walled and drained it in the sixteen twenties, and most of the island still lies below the level of a spring tide, kept dry by a raised sea wall and a network of ditches and pumps. The land is soft alluvium and clay, the horizon is flat in every direction, and the air coming off the estuary carries salt. Every one of those facts changes how a rooflight is specified and fitted here.
The housing follows the same history. Canvey filled up with holiday chalets and self built bungalows from the nineteen twenties onwards, and after the nineteen fifty three flood it was rebuilt and extended in waves. The result is an island of single storey homes with shallow roofs standing in the most exposed position in south Essex. This page works through what that combination asks for.
- 01 Soft ground, settlement and roofs that are no longer flat
- 02 Salt air, and the fixings and finishes it selects
- 03 Exposure with nothing upwind for miles
- 04 Driven rain, and why the upstand goes higher here
- 05 Shallow pitches, and which units are eligible
- 06 Bungalow plans, and the rooms daylight never reaches
- 07 Sun tunnels through a shallow void
- 08 Chalet conversions, and the rear slope behind the dormer
- 09 What is on a Canvey roof
- 10 Flat roofs on an island where water does not drain away
- 11 Moss, algae and the drainage route around a kerb
- 12 An open sky, and the glass that manages it
- 13 Humid air, cold glass and the two kinds of condensation
- 14 Narrow roads, deep plots and where a scaffold stands
- 15 What the survey settles on Canvey
- 16 Getting a Canvey Island enquiry moving
Soft ground, settlement and roofs that are no longer flat
Alluvial ground compresses. A house founded on reclaimed marsh settles more than one founded on gravel, and it rarely settles evenly, because the depth and the composition of the deposit vary across a single plot. Over sixty or eighty years that shows in the building.
The relevance is the roof plane. A pitched slope that has moved is no longer a true plane, so an opening is set out from the rafters as they actually sit rather than from an assumed grid. On a flat roof it matters more, because a fall of one in eighty is a shallow thing to begin with and a small amount of differential settlement can reverse it. The survey looks for standing water and for staining that shows where water has been, since a fall that has flattened has to be corrected before glass is set into it.
Salt air, and the fixings and finishes it selects
Airborne chloride is the reason coastal buildings age differently. Salt in solution accelerates corrosion, and on a roof it collects in exactly the places that matter: fixing heads, flashing laps, screw threads and the cut edges of metal.
The response is specification. Austenitic stainless fixings rather than plated steel. A good polyester powder coat on any aluminium frame, in a grade intended for a marine environment, since a standard coating chalks and loses adhesion faster in this air. Lead or a properly coated aluminium flashing rather than a bare mill finish. None of it is exotic and none of it is expensive at order. All of it is expensive once a fixing has failed inside a completed detail.
On Canvey the fixing schedule deserves as much attention as the glass, because salt finds the metal long before it finds the sealant.
Exposure with nothing upwind for miles
Wind loading on a roof depends on terrain as much as on wind speed. Buildings in a town are sheltered by their neighbours; buildings on open, flat, low lying ground near the coast are in the most demanding category the standards recognise. Canvey is that category almost everywhere, and the parts facing the estuary and the creek have no shelter at all.
For a rooflight the load is suction. Air accelerating over a roof lifts, and the strongest local suction sits within about a metre of ridges, hips and verges. The answer is fixing brackets at the manufacturer’s closest permitted spacing, every fixing landing in structural timber rather than in a batten, increased flashing side laps, and mechanical fixing of every tile lifted and re-laid around the opening rather than trusting the nib.
Driven rain, and why the upstand goes higher here
Exposure is also measured for wind driven rain, and the estuary edge sits in a severe category. Rain arriving at an angle behaves differently from rain falling onto a surface. It is pushed up the vertical face of an upstand and forced under the edge of a flashing, and at a low pitch it can be travelling up the roof faster than gravity is taking water down it.
On a flat roof unit the industry figure of one hundred and fifty millimetres from finished surface to the top of the kerb is the floor on Canvey rather than the target, and on a fully exposed plot going beyond it is money well spent. On a pitched slope it argues for the full side flashing depth, generous head cover, and the underlay dressed properly into the opening rather than trimmed off flush.
Shallow pitches, and which units are eligible
The island’s bungalow roofs are shallow, some of them very shallow, and pitch is the fact that decides which products can even be considered.
Most roof windows are warranted from fifteen degrees. A small number are rated from ten with a specific underlay and flashing detail. Below that no manufacturer will stand behind the weathering of a pitched unit, and on an exposed coastal roof that limit is not a technicality to be argued around. A slope measuring eleven or twelve degrees selects a different approach: a kerb mounted flat rooflight on a purpose built upstand, which is a detail designed for water that does not run off quickly.
Bungalow plans, and the rooms daylight never reaches
The advantage of a bungalow is that every room sits directly under the roof, so any of them can be lit from above with no upstairs in the way. The disadvantage is that a bungalow plan is usually wide and shallow with a corridor down the spine, and the spine gets nothing.
That makes Canvey a productive island for roof glazing. An inner hallway, a windowless bathroom or a utility can be given real daylight without touching an external wall. What decides the method is the depth of the roof void, what is running through it, and whether the room has any roof edge of its own to work with.
Sun tunnels through a shallow void
Where a room has no usable roof edge, a sun tunnel is the tool: a collector on the outer surface, a rigid highly reflective duct through the void, and a flush diffuser in the ceiling below.
A bungalow gives the short, straight run a tunnel wants, since every bend and every additional metre costs light. On Canvey the complication is usually what shares the void, because decades of extension have filled these roof spaces with old tank positions, bathroom extract ducts and cabling. The collector also wants a low profile on an exposed roof, so a flush glazed dome rather than a tall one, fixed to the same schedule as everything else up there.
Chalet conversions, and the rear slope behind the dormer
A large number of Canvey bungalows have already had rooms put into the roof, with a dormer on one elevation and nothing on the other. The dormer lights half the space and the rest sits under an unbroken slope.
A pair of roof windows in that slope is normally the whole answer, and the constraints are internal: the knee wall height, the collar position, and where the sloping ceiling meets the flat one. A unit set too high looks into the void above the collar rather than into the room. Where the roof space is used for sleeping, the openable clear area of a window in it also has to satisfy the escape requirement, which is a set of dimensions rather than a judgement call.
What is on a Canvey roof
The covering chooses the flashing kit, and the island’s rebuild history has left a fairly narrow but distinctive range.
| Covering | Where it turns up | What the detail needs |
|---|---|---|
| Concrete interlocking tile | Post-war rebuilding and most re-coverings | Deep profile kit matched to the pan, mechanically fixed on re-laying |
| Plain clay tile | Surviving interwar bungalows and the older cottages | Soaker kit dressed between courses |
| Felt and mineral cap sheet | Older flat rear additions and garages | Membrane dressed up a kerb and terminated under the unit |
| GRP and single ply | Recent flat roofs and re-coverings | Bonded upstand, welded or laminated at the corners |
Flat roofs on an island where water does not drain away
Canvey drains slowly by design, because the whole island is a managed water table behind a wall. That is a groundwater matter rather than a roof one, but the habit of thinking about drainage carefully is worth carrying up the ladder.
A flat roof is laid to a fall, conventionally a minimum of one in eighty as designed, to allow for deflection and construction tolerance. Water standing more than about forty eight hours after rain is ponding, and ponding against a rooflight kerb is the condition that finds any weakness in the perimeter. Where a survey finds it, the fall is sorted first. Setting glass into a roof that holds water is building in an argument.
Moss, algae and the drainage route around a kerb
Damp maritime air, low ground and slow drying roofs suit organic growth. North facing slopes on the island green up quickly, and moss around a rooflight upstand does something worse than look untidy: it holds water against the covering and gradually closes the path that water was meant to take away from the detail.
The maintenance is a few minutes with a gloved hand around the kerb and along the gutters each autumn. Most water problems that appear around rooflights begin as a drainage route that quietly closed itself, and on Canvey it closes faster than it does inland.
An open sky, and the glass that manages it
There is nothing to shade a Canvey roof. No hills, few mature trees, and on much of the island no building taller than a bungalow for a considerable distance. A rooflight here sees the whole dome of the sky from first light to last.
That is the reason roof glazing performs so well on the island, delivering something in the order of two to three times the illuminance of a vertical window of the same area. It is also the reason solar control glass with a low g-value is close to compulsory on any south or west facing plane. The specification balances two numbers that pull against each other: the U-value governs heat loss in February, and the g-value governs whether the room is usable in August.
Humid air, cold glass and the two kinds of condensation
A bungalow on low, wet ground concentrates moisture. Kitchen, bathroom and bedrooms all sit on one floor under one roof, external humidity is high for much of the year, and the warm damp air inside has nowhere to go but up against the coldest surface in the room.
Water forming on the room side of the glass is surface condensation. It is physics rather than a fault, and it is managed with ventilation and with a better glazing specification, because a warmer inner pane condenses less. Misting between the panes is a different matter: the sealed unit has lost its seal, the desiccant is saturated, and that unit has reached the end of its working life and wants replacing. The third thing people find is water tracking down the inside of a reveal, which usually means the vapour barrier around the opening was never continuous, and that is a detail settled during installation rather than afterwards.
Narrow roads, deep plots and where a scaffold stands
The island’s residential roads are narrow, parked on both sides, and many of the plots are long with a bungalow set back behind a driveway. Getting boards and tube to a rear roof usually means carrying them down the side of the building rather than lifting them off a vehicle.
On a single storey building the scaffold itself is modest, which helps. What matters more is the delivery window and somewhere firm for a lorry to stand, and on soft ground after a wet week that is a real question rather than a formality. It is settled at survey and it appears in the fixed figure.
What the survey settles on Canvey
The survey measures the pitch rather than estimating it, since so much here sits close to the limit. It establishes the covering and its condition, finds the rafters and any purlin as they actually are, checks the void depth and what shares it, and looks hard at drainage on any flat area.
It also sets the exposure specification: fixing centres, fixing material, flashing laps, upstand height and coating grade. Those five decisions are what separate a rooflight that survives twenty winters on this island from one that does not, and none of them is visible once the job is finished.
Getting a Canvey Island enquiry moving
The Building Control notification is handled as part of the job. Sunspire gives a range by email once the roof plane, the covering and the room are known, then a fixed written figure once the survey has confirmed the structure, the exposure and the access. Sunspire fits new rooflights and replaces units that have reached the end of their working life.
The mainland towns across the creek are covered on the same terms, including Benfleet and Basildon, and the full service area is listed on the areas we cover page. The roof is closed and watertight at the end of every working day, and the workmanship carries a ten year guarantee.
Also covered
Near Canvey Island
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We start with the building, the covering and the slope. Then we tell you what will suit it, and what it will cost, as a fixed written number.
- Surveyed before it is priced
- 10-year workmanship guarantee
- Building Control notification handled
- New installations and replacements