Rooflight Installation in Faringdon

Buildings never meant for living

A market town accumulates ancillary buildings. Behind the older frontages there are coach houses, stables and stores that once served the property in front of them, around the yards there are workshops put up for a trade, and out along the lanes there are barns and cart sheds that stopped being farmed decades ago. Faringdon has more of this stock relative to its size than a suburb does, and much of it is being converted.

What matters about them is what they were built to do. A stable was built to keep animals dry, a store to keep goods dry. Neither was built to be pleasant to sit in, and nobody putting one up was thinking about daylight beyond enough to see by. So the walls are thick and often solid, openings are few and small, the plan can be deep, and the roof is frequently the largest single element of the building.

That inverts the usual brief. In a house a rooflight adds light to a room that already has a window. In a converted outbuilding it is often the whole daylight strategy for the space beneath, so its size and position decide whether the room is usable or dark.

Daylight from above, or none

Once the roof is doing the work, the questions change order. Instead of asking where a unit will fit between rafters, we start by asking where the light has to land.

Wall openings in these buildings are constrained. On a converted barn they sit where the doors and vents were, which is rarely where a room wants a window. Cutting new ones into a solid wall is a structural and, on a designated building, a consent question of its own, and on a boundary wall there may be no elevation available at all. The roof is often the only surface with room to work.

So we look at the plan before the roof. Where the sleeping spaces are, which parts of the floor sit furthest from any wall opening, and which way the building faces. A single unit over a landing lights a landing. The same unit moved along the slope may light a stair, a corridor and the room at the end of it. On a deep plan, light from one slope alone leaves a shadow down the far side, so both slopes come into the conversation.

Orientation then decides specification rather than position. A large area of glass in a south-facing slope will gain heat, and that is answered through the glass, the opening method and any shading rather than left to be discovered in July.

Seen against an open frame

The second difference is visual, and it is the one people are least prepared for. Most conversions of this kind keep the roof open. The point of the building is the volume, so the trusses, purlins, rafters and tie beams stay exposed and the ceiling, if there is one, follows the line of the roof.

In that situation a rooflight is not a hole in a flat plane. It is an object seen against a timber frame, from below and from across the room, usually at some distance because the space is tall. If the head of the unit sits just below a purlin, the purlin shadows it. If it lands hard against a truss, the frame crops it. Two units set out without reference to the bays look scattered even when each one is individually in the right place.

So on these roofs we set out against the structure, not only against the covering. The bays between trusses give a rhythm, and units placed to it read as though they belong to the building. The depth of the reveal matters too, because in a tall room you look up into the liner rather than glancing at it. A splayed reveal spreads light further into the space and reads better from below than a square-sided box.

None of this removes the structural question, which comes first. Trusses, tie beams and purlins in an old agricultural roof carry load and are not cut into on the day. Where an opening cannot avoid a member, that is a designed alteration belonging to whoever is engineering the conversion, and we detail the weathering around what they specify.

A roof that never had insulation

Changing an ancillary building to habitable use brings the whole Building Regulations picture into scope, and the roof is a large part of it. A barn or stable roof was often nothing more than a covering on battens over the structure, with daylight visible between the slates and no insulation in it at all. That has to change, and the change decides what our unit sits in.

Two routes get used. Insulation can go above the structure so the timbers stay exposed inside, which lifts the covering and increases the depth of the roof. Or it can go between and under the rafters, which keeps the external line but loses depth internally and covers timber the owner may want to see. Either way the roof becomes thicker, and the build-up gains layers it never had: insulation, a vapour control layer on the warm side, and a breather membrane or a ventilated void depending on the design.

The consequence for us is depth and continuity. The kerb or upstand height has to suit the finished thickness rather than the original one, the liner has to reach from the unit through the full build-up to the internal finish, and the vapour control layer has to be carried around the opening and sealed to the frame without a break. A gap at that junction puts warm moist air into a cold build-up, and the result shows up later as damp timber rather than as anything dramatic.

We do not design the roof build-up. Where an architect or designer has specified it we install to that specification, and we ask for it early because it changes what we order.

Consent, and the roof elevation

Whether an outbuilding or barn can become a dwelling at all is a separate question from the rooflight, and it is settled before anybody talks to us about glass. It may be a full planning application, and there are permitted routes for certain changes of use with conditions attached. The rooflight sits inside that larger consent rather than beside it.

Faringdon lies in the Vale of White Horse district, so the planning authority for an address here is Vale of White Horse District Council, not Oxford City and not West Oxfordshire. The town has a conservation area covering its older part, with listed buildings in and around it. Listed status and conservation area boundaries are matters of public record, established at the address rather than assumed from the age of a building. Where a building is listed, listed building consent is separate from planning permission, and a curtilage building can be caught by the listing of the main house.

On an ancillary building the roof is very often the sensitive elevation, which surprises people who expect the walls to be. These buildings are low to the eaves and broad, so the roof can be the largest surface they have, and on a barn in open country it is seen from a long way off.

We install rooflights and we are not the body that decides. We will say what specification usually satisfies a sensitive roof and coordinate with your architect or agent.

What suits an agricultural building

Rooflights are not foreign to these buildings. Barns, workshops and stores have had them for a very long time, and the traditional version is plainly functional: a glazed light set into the covering, the size of the units around it, with no ornament and no deep frame. That history tells you what the building will accept.

The unit that usually suits is the modest, flush one. A dark external finish, a low profile sitting in the plane of the covering rather than proud of it, and slim framing. On a designated building a conservation-pattern unit with a single vertical bar is a familiar answer. What sits badly is anything domestic-looking: a wide unit with heavy trim, a pale frame, or large windows spaced as they would be on a house slope.

Arrangement follows the same logic. A regular rhythm of smaller units set to the bays generally reads better on a long agricultural roof than one or two very large openings, and spreads light more evenly through a deep plan. A single large area of glass is achievable, but it is a decision with an external consequence.

The stone core and newer estates

Not every Faringdon enquiry is a barn. The older streets around the Market Place and the town hall are built of local stone, roofed in stone slate, clay tile and slate, and much of that area falls in the conservation area. There the visible slope is the constraint, and a flush unit in a dark finish, set into the plane of the covering, usually suits both the roof and the setting.

Access is the other town issue. Yards behind the Market Place frontages can be reached only through an archway or a side passage, and a scaffold that is straightforward on an open site becomes an exercise in itself there. Where a shared surface or a neighbour’s ground is involved, that is established before a date is given.

Beyond the old streets, Faringdon has grown outwards in the ordinary way. The estate housing is concrete interlocking tile on trussed rafters, with consistent pitches and modern underlay, and there the work is routine: a flashing kit made for the tile profile, an opening between trusses, and a unit sitting at the depth it was designed for. Many of those enquiries are replacements, where an older unit has misted or a frame no longer closes properly. The old unit comes out, the timber around the opening is inspected while the roof is open, and a new unit goes in on a sound upstand with new flashings. New installations and replacements are the whole of our scope.

What we settle before quoting

A Faringdon job is priced after five things are known.

What the building is, and what it was. House, converted outbuilding, or a conversion still in progress. On an ancillary building we want to know what stage the wider project has reached, because a rooflight specified before the roof build-up is decided usually has to be respecified.

The structure and the covering. Trusses, purlins, tie beams and rafter depth in an open roof, whether the frame has moved over a long life, and where on the slope the opening would sit. This is looked at at roof level.

The build-up the unit sits in. Existing thickness, proposed insulation position, vapour control layer and finished internal line. That decides upstand height, liner depth and what we order.

The consent position at the address. Listed or not, inside the conservation area or not, and what the conversion consent already says about the roof. Where drawings exist we work to them.

Access. Scaffold position, the route in, and whether the working area is shared. Easy on a farm building, and often the item that sets the date in a town yard.

We handle the Building Control notification as part of the job, our workmanship carries a ten-year guarantee with coverage and exclusions written out on its own page, and we have been installing rooflights for fifteen years. Faringdon sits towards the western edge of the twenty five mile road radius we work from Oxford. It is inside it and we cover it, and where an address further west falls outside we say so at the enquiry rather than after a survey.