Roof Lantern Installation
Flat-roof glazing sized to the room and detailed into the kerb below it.
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Mid Essex
Rooflight installation in Rettendon
Ridge village, exposure and wind. What that means for getting glass into a roof here is the whole of this page.
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10-year guarantee
RettendonTown covered
Mid EssexWithin
30Mile radius by road
10Year workmanship guarantee
In Rettendon
What we install on Rettendon 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 Rettendon roofs
Rettendon sits on a ridge of high ground between the Chelmer and the Crouch, and that single geographical fact changes the specification of almost every rooflight installed in the parish. Wind is the governing load here in a way it simply is not on a sheltered street in town. Fixings, laps, tile mechanical fastening and the sequence of the work all shift as a result.
The building stock is varied. All Saints stands high on the hill with older houses gathered around it, Rettendon Common carries a loose spread of bungalows and plotland-era stock, ribbon housing runs along the older main road, and the A130 now cuts through the parish on its way south. This page works through what an exposed hilltop position does to the job, and what the survey records before a figure is fixed.
- 01 A village on a ridge, and what the height does to the job
- 02 Wind loading, and where the figures for it come from
- 03 Tile fixing in an exposed zone, and re-laying around an opening
- 04 Rain arriving sideways, and the head lap that answers it
- 05 Holding a flat rooflight kerb down against uplift
- 06 Rettendon Common, and the stock that grew up there
- 07 Bungalows on the Common, and the pitch they were built at
- 08 All Saints on the hilltop, and the houses standing near it
- 09 Hyde Hall, and the microclimate the gardeners work in
- 10 The A130 through the parish, and the plots either side of it
- 11 Ground falling away towards Battlesbridge and the Crouch
- 12 Sun on an exposed southern slope, and the overheating that follows
- 13 Shelter belts, hedgerows and the light they hold back
- 14 Scaffolding on high ground, and working to a forecast
- 15 Building Regulations for a Rettendon rooflight
- 16 Getting a figure for a roof on the ridge
A village on a ridge, and what the height does to the job
The land around All Saints rises well above the surrounding levels and the ground falls away in several directions from it. There is little in the way of continuous shelter to the west and south, which is the direction the prevailing weather arrives from. The effect is that a roof here sees a higher wind speed than an identical roof a few miles away in a valley.
That does not make the work harder to do well. It makes the specification less forgiving. Details that would survive on a sheltered roof for years while being slightly wrong will announce themselves in the first winter here. The perimeter detailing carries the job, which is why the workmanship is covered by a ten-year guarantee.
Wind loading, and where the figures for it come from
Wind load on a roof is calculated, not guessed. The basic wind speed for a site comes from a map, then gets modified for altitude, distance from the coast, terrain roughness and the topography around the building. A ridge or an escarpment produces a topographic multiplier because air accelerates as it is forced over rising ground.
Rettendon has both the altitude factor and the topography factor working in the same direction. The result is a design pressure at the roof perimeter and corners noticeably higher than the general field of the roof. Corners and edges are always the worst zones on any roof, and on a hilltop they are worse again. Fixing centres are set from that pressure, not from habit.
On exposed ground the fixing schedule is derived from the calculated pressure, not copied from the last job.
Tile fixing in an exposed zone, and re-laying around an opening
British Standard 5534 requires every tile on a roof to be mechanically fixed where the calculated uplift demands it, and on exposed sites that generally means all of them rather than every third course. Older roofs in the parish were often laid before that expectation hardened, so the tiles around an opening may come off more easily than they should.
Tiles lifted to form a rooflight opening are re-laid to the current standard, clipped and nailed, and the perimeter courses around the new unit get particular attention because they sit in the zone with the highest local pressure. Dry fixed ridge and hip systems are the same principle applied to the top of the roof: a mechanical fixing rather than a bed of mortar holding a tile down in a gale.
Rain arriving sideways, and the head lap that answers it
Rain on an exposed ridge does not fall vertically. It arrives at an angle, driven across the slope, and it can be pushed up a lap rather than running down it. Every weathering detail on a rooflight assumes water travelling downhill under gravity, so an exposed site has to build in more margin than the minimum.
In practice that means generous head laps on the apron flashing above the unit, side skirts dressed well into the tile line rather than sitting on top of it, and underlay lapped and supported so that any water reaching it is carried out over the flashing and not behind it. On a steeper slope the demand eases, because the water leaves faster. Rettendon has both steep older roofs and shallow post-war ones, and the two are detailed differently.
Holding a flat rooflight kerb down against uplift
A flat rooflight on an exposed site is subject to suction, not pressure. Air passing over the top of a raised unit accelerates and creates a lifting force, and the whole assembly has to be held down against it: the glass to the frame, the frame to the kerb, the kerb to the deck, and the deck to the structure below.
The weak point is usually the kerb to deck connection on a timber deck, particularly where a kerb has been formed loosely rather than built as a structural upstand. A properly built kerb is a timber box fixed through into the joists or into noggins between them, at centres derived from the corner zone pressure. The membrane is then dressed up the outside of it and terminated under the frame, so that the fixings never sit in the wet.
Rettendon Common, and the stock that grew up there
The Common is a scattered settlement rather than a street, with houses on wide individual plots, deep front gardens and a good deal of self-built and progressively extended stock. Roofs there are frequently a sequence of additions rather than one design, and it is common to find three coverings on one building.
Practically that means a survey has to look at each plane on its own. A concrete tile main roof, a felt garage, a later single ply rear addition and an original clay tiled outshot each want a different method at the opening. Where a covering has reached the end of its life, glass is not set into it until that is dealt with.
Bungalows on the Common, and the pitch they were built at
There are a lot of bungalows in this parish, and they are good buildings for rooflights. A single storey roof puts the glass directly over the living space, so the daylight gain is immediate and no light well is needed. The catch is pitch.
Some post-war bungalow roofs run at twenty degrees or less. Every roof window has a published minimum pitch and it is not a suggestion, since below it the flashing cannot develop enough fall to shed driven rain. Where the slope is too shallow for a standard roof window, the answer is a flat glass unit on a purpose-built kerb, sometimes with a pitched adaptor. That is covered further on the roof window installation page.
All Saints on the hilltop, and the houses standing near it
The church sits at the highest point with a long view south, and the older buildings near it are the parish’s most protected. Plain clay tiles, some slate, low eaves and steep slopes. Where a building here is listed or sits in a designated area, the position of any glass is agreed with the planning officer before a unit is ordered.
The unit that satisfies an officer has a recognisable shape: slim frame, dark finish, a central vertical bar so the opening reads as two panes, and a profile that sits within the plane of the tiles. Depth is the visual test, since a surround standing fifty millimetres proud is visible from the lane. A conservation rooflight set flush disappears at any distance.
Hyde Hall, and the microclimate the gardeners work in
The RHS garden at Hyde Hall sits on the same hill in this parish, and it is worth knowing why. It is one of the driest and windiest gardens in the country, planted with that in mind, and the gardeners there work with a specific set of conditions: low annual rainfall, high evaporation and persistent wind across an open hilltop.
Those conditions apply to the roofs around it. Less total rainfall does not reduce the weathering demand, because what does arrive is driven hard. High wind also dries a roof quickly, which is good for moss but hard on anything that relies on a seal being protected by shelter. Mechanical fixing and physical laps do the work on a roof here, with sealant as a secondary line rather than the primary one.
The A130 through the parish, and the plots either side of it
The dual carriageway runs through the parish towards the Rettendon turnpike junction, and houses within a few hundred metres of it carry a continuous traffic sound that rises and falls with the wind. On an exposed site the noise carries further than it would through trees.
Where a bedroom or a home office is gaining a rooflight on that side, the glazing specification changes. Asymmetric pane thicknesses in the sealed unit, an acoustic laminate interlayer in the outer pane, and full perimeter compression on the frame all contribute. It is also worth noting that a heavier laminated outer pane happens to improve rain noise on the same roof, which on an exposed slope is a useful side effect.
Ground falling away towards Battlesbridge and the Crouch
The southern edge of the parish drops towards Battlesbridge and the head of the Crouch, and the ground down there behaves nothing like the hilltop. Low lying, slow draining, and sheltered enough that the wind problem largely disappears while a damp one takes its place.
On the low ground the survey concentrates on falls and on ventilation rather than on uplift. A flat roofed addition that has settled slightly on soft ground loses its fall, water stands, and standing water against a kerb finds any weakness beneath it. Anything still holding water forty eight hours after rain is ponding and gets corrected before glass goes in.
Sun on an exposed southern slope, and the overheating that follows
An open hilltop means very little is shading the roof. A south facing slope in Rettendon receives an almost unbroken run of sun from mid morning to late afternoon in summer, with no neighbouring building or tree line taking the edge off it.
Glass on that slope needs a solar control coating, and the figure to look at is the g-value, which is the proportion of solar energy passing through the unit. Standard double glazing runs somewhere near 0.6. A solar control unit brings that down towards 0.3 to 0.4, which roughly halves the summer heat gain while keeping the light. On a bedroom or a kitchen with a lot of south facing glass, that specification is decided at order, not afterwards.
Shelter belts, hedgerows and the light they hold back
The plots along the older lanes tend to be bounded by mature hedgerow and shelter planting that was put there to break the wind. It works, and it also blocks a good deal of low winter sun from reaching a window in the wall.
This is precisely the situation where roof glazing outperforms a window. A rooflight sees the sky rather than the horizon, so a hedge or a line of trees on the boundary takes almost nothing from it. A north facing roof slope with a clear view of open sky can deliver a steadier, more usable light through the day than a south facing wall window looking into a shelter belt.
Scaffolding on high ground, and working to a forecast
Scaffold on an exposed site is tied and braced to a different standard, and sheeting a scaffold on a hilltop turns it into a sail, so it is either left unsheeted or tied to suit the additional load. The ground has to carry the standards, which on a soft verge or a lawn means sole plates and spreaders.
The work itself is planned around the forecast. Stripping a covering and forming an opening are the moments when the roof is vulnerable, and neither is started into rising wind. The roof is never left open overnight. On an exposed site that is not a slogan, it is the reason the sequence is planned around the weather window rather than around the diary.
Building Regulations for a Rettendon rooflight
Rettendon falls under Chelmsford City Council. Forming a new opening in a roof is notifiable work, because it alters the structure and creates a new thermal element in the envelope. Part A covers the trimming, Part L the U-value, Part F the ventilation where it is affected, and Part B where a loft has become a habitable room.
On an exposed site the structural side gets more attention than it might elsewhere, since the fixing of the unit and the re-laid covering both have to satisfy the calculated uplift. Sunspire handles the notification as part of the job, and the wider picture of what triggers an application sits on the guides section.
Getting a figure for a roof on the ridge
Sunspire fits new rooflights and replaces units that have reached the end of their life, working to two figures: a range by email once the basics are known, then a fixed written price after a survey. Rettendon is a straightforward run from Chelmsford down the A130, and the parish sits comfortably inside the working area set out on the areas we cover page.
To get a useful range, send a photograph of the roof slope taken from the garden, one of the ceiling or loft from inside, the approximate room size and a note of how exposed the plot is. Whether the house sits on the hill or down towards the low ground genuinely changes the specification. The general cost drivers apply here as anywhere, with exposure, access and roof structure carrying the most weight.
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