Conservation Rooflight Installation
Slim cast frames set flush, for stone slate, listed and conservation roofs.
the Cotswolds
Rooflight and skylight installation in Fairford, and the roof it has to sit in.
Around Fairford you are mostly dealing with small town on the Coln, stone and render, and that decides more about a rooflight than the rooflight does.
- Covered from Gloucester
- 15 years on Gloucestershire roofs
- 10 year workmanship guarantee
- From Gloucester by road
- 15 to 30 milesApproximate, and inside the 30 mile radius
- Dominant roof stock
- Cotswold stone slate in diminishing coursesWhat the covering is decides the detail
- The usual constraint
- Conservation consent and matching the stoneSettled at survey, before anything is ordered
- Local character
- small town on the Coln, stone and renderRecorded for Fairford specifically
In Fairford
Rooflights we fit around Fairford
Roof Lantern Installation
Flat roof glazing sized to the room and detailed into the kerb it stands on.
Flat Roof Rooflight Installation
Flush and kerb mounted units into felt, single ply and GRP flat roofs.
Roof Window Installation
Roof windows trimmed into slate, clay and concrete tile without proud flashing.
VELUX Window Installation
VELUX fitted alongside Fakro, Keylite and Roto, chosen to suit the roof.
Electric and Opening Rooflights
Actuated openers, rain sensors and controls, wired and commissioned.
The local detail
Fifteen things worth knowing about Fairford roofs, worth reading before the survey.
Fairford is a working small town rather than a preserved village, and the useful thing to understand before anybody quotes for a rooflight here is that its housing stock is genuinely mixed. There is a historic core around the market place and the church, built in limestone with stone slate over it. There is Georgian and Victorian building in stone with render and with Welsh slate. There is a large amount of twentieth century housing, some of it associated with the airfield, roofed in concrete interlocking tile. And there is the River Coln running through the low ground on the south side of the town. Which of those you own decides the method, the consent position and the price, and none of them is the default. Severn Skylights Gloucester travels out to Fairford from Gloucester and starts every enquiry here by working out which Fairford it is looking at.
Fairford is not one building type, and the survey starts by deciding which one you own
In a village where every building is stone slate over rubble, an installer can arrive with a fixed method. Here that would be wrong more often than right. The town grew as a wool town, was rebuilt in parts through the Georgian period, took Victorian additions, and then expanded substantially in the twentieth century.
So the first questions are ordinary and they matter: what is the covering, what is the pitch, what is the wall construction behind the eaves, is the roof structure cut on site or trussed, and is the building within the conservation area or listed. Two houses four hundred metres apart in Fairford can produce quotations that differ by a large multiple, and the reason is entirely the roof rather than anything else.
The market place frontages, and stone slate on the old core
Around the market place and along the older streets the building is limestone with stone slate roofs, laid in diminishing courses with the largest and thickest slates at the eaves and the gauge reducing continuously up to the ridge. Under it there are riven battens and often a lime mortar torching sealing the joints from below in place of any underlay.
An opening in that cannot be cut and closed around a frame. The courses above are stripped back up the slope, the frame is set, and the courses are re-laid downwards to re-establish the original rhythm, with reclaimed stone found to match thickness and colour where slates break in the process. The covering method in full is on rooflights in natural slate roofs, and on this part of Fairford a slim conservation unit with a single central glazing bar is usually the right specification, covered on conservation rooflight installation.
Render over rubble, and what the wall does at a reveal
A good deal of Fairford building is rubble limestone with a render or a lime wash over it rather than dressed ashlar, and the walls are thick and irregular. That is a wall detail rather than a roof detail, but it turns up at the reveal.
Where a rooflight sits low on a slope, close to the eaves, the plastered reveal below the cill runs down onto the head of a wall that may be 500mm of uncoursed rubble with a hollow core. Fixing into it is not the same as fixing into brick, insulation continuity across the wall head is frequently poor, and that junction is exactly where a cold bridge shows up as black spotting in February. The reveal detail on these buildings takes the insulation right across the wall plate and the vapour control layer is taped to the frame rather than trimmed short of it.
The Coln, the old mill, and the low ground on the south side
The River Coln runs along the southern edge of the town past the mill, and the ground there is low. Properties on that side have the usual consequences of a river frontage: a damper roof void, more moss and lichen growth on north facing slopes, and homeowners who have thought about water more than most.
The practical survey response is to read the roof void properly rather than assume. Moisture readings are taken at the wall plate as well as around any existing opening, because damp arriving through a wall head from below produces the same stains in the same corners as a weathering failure above, and the two are corrected in completely different ways. Where an existing unit is involved, the diagnostic table on replacing a failed or misted rooflight separates the common causes.
The covering
Cotswold stone slate laid in diminishing courses on torched battens, the covering that decides the whole detail.
Cotswold stone slate in diminishing courses, which is what the survey is looking at before it looks at the glass.
Twentieth century Fairford, and the most straightforward roofs in town
A large part of the town’s housing is post-war and later, in brick or reconstituted stone, roofed in concrete interlocking tile at 25 to 35 degrees. These are the easiest roofs Severn works on anywhere in the county.
The tiles unclip and lift, a standard manufactured flashing kit exists for the profile, the covering goes back in an afternoon and nothing needs sourcing from a reclamation yard. The constraint on these houses is not the covering, it is the structure and the shape. A hipped roof narrows towards the corner, so the usable rectangle is considerably smaller than the roof looks from the garden, and a purlin across the middle plus a binder in the ceiling can leave surprisingly little clear run. Two units in adjacent rafter bays usually give more glass and better light than one wide one, and need no structural design at all.
Trussed roofs on the newer Fairford estates
The later estates are trussed rafter construction: factory made triangulated frames at 600mm centres, joined with punched metal nail plates, designed to work as a whole. Cut a web to make room for a window and the load path changes, the truss deflects, and the evidence turns up as a sagging ceiling line months later rather than as a noise on the day.
So the opening works with the trusses. Between two trusses at 600 centres there is roughly 550 to 570mm of clear width, and the manufacturers make narrow units precisely for it, typically 550mm wide by 780, 980 or 1180mm long. A unit in that range needs a head and cill trimmer between the two trusses and nothing else. Anything wider means carrying part of a truss on a designed member spanning to the trusses either side, which is an engineer’s calculation and a Building Control approval before the covering comes off. That is regularly the right thing to do for a loft room, and it is a different job with a different programme. The rules are on rooflights in a trussed roof and what cannot be cut.
Torched battens are the reason a stone slate roof is opened carefully and closed properly.
Aircraft over Fairford, and the glass that actually helps
The airfield to the west of the town is active, and for a few days each summer it is very active indeed. Noise is a normal part of the conversation about glazing in this town in a way it simply is not in Northleach or Bibury.
What helps is laminated glass, and the reason is the interlayer rather than the thickness. A laminated pane is two sheets of glass bonded with a polyvinyl butyral interlayer that damps the vibration of the glass instead of transmitting it, and an asymmetric build, meaning the two panes of a sealed unit at different thicknesses, avoids the two sheets resonating together at the same frequency. Specifying a 6.8mm laminated outer pane on a rooflight in Fairford costs very little more at the point of order and is not retro-fittable afterwards, so it is a decision worth making at survey. It also cuts the drumming of heavy rain on a shallow flat roof unit noticeably. The numbers are on acoustic glazing and rain noise.
An asymmetric laminated build is specified when the unit is ordered, and there is no way to add it later without changing the glass.
Rear ranges behind a Fairford frontage, and where the daylight comes from
On the historic plots the building runs back from the street in ranges and wings added over time, each often at a lower level than the main range. That back land is where a rooflight proposal is strongest.
A lower rear roof is screened from the street by the main range, it is frequently enclosed by garden walls and the backs of neighbouring plots, and it is usually over the kitchen, the utility or the back stair. Establishing which slopes are genuinely unseen from any public place, including from the churchyard and from the bridge over the Coln, is a survey task done with a camera rather than by assumption, and photographs from those points are worth putting into an application before anybody asks for them.
Diminishing courses mean the slate at the ridge and the slate at the eaves are different sizes. An opening has to be set out against that, not against a tape measure.
St Mary’s, the churchyard, and roofs in the setting of a landmark
The parish church is the building Fairford is known for, and its setting is a material consideration in planning terms. Roofs that are read in the same view as a highly graded listed building attract more careful assessment than roofs elsewhere in the same town.
That is not an obstacle so much as a reason to be precise. Where a slope is visible in a view that also contains the church or the churchyard, the application benefits from a photograph taken from the point that view is had from, with the proposed unit marked to scale. Officers assess what is visible from public places, and giving them the view rather than making them go and find it tends to produce a faster and better answer. The consent framework across the district is set out on conservation areas and listed buildings in Gloucestershire.
Where consent bites in Fairford and where it is straightforward
The planning authority is Cotswold District Council, the historic core is a conservation area, and there is a body of listed building within it. Outside that core, a large part of the town is undesignated twentieth century housing where a rooflight goes in under permitted development with no application at all.
The limits still apply everywhere. An alteration to the roof of a house must not project more than 150mm beyond the plane of the existing slope, and must not be higher than the highest part of the existing roof. That single figure is why an in-plane roof window is almost always permitted development while a bulky kerb mounted unit on a pitched slope may not be. Side facing units in a room in the roof need obscure glazing and must be non-opening below 1.7 metres above floor level. Flats have no permitted development rights for roof alterations at all. The detail is on permitted development limits for rooflights.
On Fairford roofs Conservation consent and matching the stone.
Loft conversions in Fairford, and the escape opening rule
A rooflight going into a habitable room in the roof engages the fire safety requirements, and this is the point where a specification most often has to change after somebody has already chosen a unit they like.
Where the roof window forms the escape opening from a loft room, the clear openable area must be at least 0.33 square metres with a minimum of 450mm in both height and width, and the bottom of that opening must sit between 800 and 1100mm above the floor. A fixed unit in that position does not satisfy it, and neither does a centre pivot sash that does not swing far enough clear. On a steep stone slate roof in the old part of town, the height rule interacts awkwardly with the coursing, because the position that suits the escape rule may not be the position that suits the course boundary. That gets resolved at survey. The full requirement is on roof window escape openings and the rules.
Flat roof rooflights on a Fairford rear extension
Single storey rear extensions are common across the newer parts of the town and increasingly on the older plots too, and a made-to-size flat roof unit or a lantern over one is a frequent enquiry.
Three numbers govern it. The upstand is 150mm measured from the finished surface of the waterproofing at the high point of the fall, not from the deck and not from the low corner. The deck is laid to a designed fall of around 1:40 so the finished fall after deflection is no shallower than 1:80. And the glass itself is set at a minimum of about five degrees, because below that rain does not shed, dust stays put and the unit looks dirty within weeks. The kerb is treated timber insulated on its outer face so it is not a cold ring around the glass, and the membrane is dressed up and over it so the upstand becomes part of the roof rather than a joint. A lantern adds height and volume and is set out differently again, on roof lantern installation.
the Cotswolds
Diminishing courses mean the slate at the ridge and the slate at the eaves are different sizes. An opening has to be set out against that, not against a tape measure.
The covering
Cotswold stone slate laid in diminishing courses on torched battens, the covering that decides the whole detail.
Cotswold stone slate in diminishing courses, which is what the survey is looking at before it looks at the glass.
Access, parking and working in a small market town
Fairford is easier to get scaffold into than most of the wolds villages, which is worth saying plainly because it shows up in the price. The estates have driveways and turning space. The town is on a main road with a market place that a lorry can reach.
The exceptions are the older plots where the only route to the rear is through the house or down a passage between buildings, and any position where a licence is needed to stand scaffold on the highway. Those are identified at survey and the lead time for a licence is built into the programme rather than discovered on the week of the start date. Coverage across this part of the district, and how far Severn travels, is on the areas pages.
What a Fairford survey measures before a unit is ordered
The order goes out against measured facts, and the list is longer on a stone roof than a tiled one.
- The covering identified properly, with slate size and measured gauge where it is stone or natural slate, and the profile and lap where it is tile.
- Pitch taken off a digital level on the actual slope rather than estimated.
- Rafter or truss centres and depth, and the position of any purlin, binder, strut or collar.
- Whether the roof is cut on site or trussed, which decides whether an engineer is involved.
- Underlay type and condition, or the presence of torching where there is no underlay.
- Insulation depth and whether a ventilation gap survives above it.
- Anything already routed through the void: tank, soil vent pipe, cabling, flue.
- Designation status for the address, and visibility of the slope from every public vantage point.
- The access route, where a lorry can turn, and where glass can be lifted from.
From a Fairford photograph to a date in the diary
Email photographs of the roof from outside, a photograph of the room from inside, the covering if you know it, roughly where the daylight is wanted and the address to info@severnskylightsgloucester.co.uk. An indicative range comes back within a day or two along with the designation position, which in this town is the fact that most changes the figure.
A survey follows, and the fixed price after it is itemised so it is clear what is unit, what is labour, what is scaffold, what is stone and what is Building Control. The notification is submitted and closed out as part of the job, the roof is never left open overnight, and the workmanship carries a ten year guarantee. Neighbouring towns including Lechlade and Cirencester have their own pages, and the costs page explains how a range becomes a fixed figure.
Also covered: the Cotswolds