Rooflight and skylight installation in Great Bentley

Facing the green

Where a property fronts the green, the roof is part of a set piece rather than an individual building, and that is how a conservation officer will look at it.

A conservation area does not by itself remove permitted development rights for rooflights on a house. An Article 4 direction does, and where one exists it commonly applies to elevations visible from a space like this. Whether one covers your address is a question for the council rather than a judgement call.

Where an application is required, the design that gets through is a conservation rooflight: sitting low against the plane of the covering rather than standing proud, upright rather than wide in proportion, with a central glazing bar, in matt black. The profile matters more than the other three combined. Include the manufacturer’s section drawing, because how far the unit stands above the tiles is the question that decides it.

On a rear slope, invisible from the green and screened by the ridge, the case is much easier and a standard unit may well be acceptable. It is worth asking rather than assuming the expensive product is compulsory, and worth describing the visibility honestly in the application because it helps.

The older property

Steep pitches, cut roofs with rafters and purlins, and coverings of clay plain tile and slate. Some listed buildings, where consent is required for a rooflight on any slope regardless of visibility.

Old clay plain tile is demanding: small, double lapped, brittle when old, and a proportion breaks on removal whatever care is taken. Matching weathered tile is genuinely difficult, and the usual answer is to take sound tiles from a rear or hidden slope so the visible elevation stays consistent.

Underneath, a roof that has never been stripped may have no underlay at all. Modern weathering assumes a membrane to lap into; where there is none the detail is built around the opening instead. Normal on a building of this age, more work, and it belongs in the quotation rather than in a conversation on the day.

The twentieth century housing

Ordinary work and much easier. Concrete interlocking tiles, pitches around 30 to 35 degrees, cut roofs on the earlier properties and trussed rafters on the later ones, off street parking and space for a tower.

Establish cut or trussed from a loft photograph before anything else. Rafters with a purlin and clear space between means a wide opening is ordinary carpentry. Triangular frames with diagonal webs joined by flat steel plates means opening width is limited to the 600mm truss spacing unless a designed trimmer is installed.

Profiled tiles need a deep flashing kit rather than the flat kit used on slate, and that is worth confirming by name on any quotation.

Extensions

Common across the village and where a good deal of our work is. The kerb decides whether the installation lasts: at least 150mm of upstand, the deck falling away from it so water cannot pond against the seal, and rigid insulation on the outer face of the kerb itself.

That last item appears on almost no quotation and matters more than the glass specification does. A 1200 by 1800 rooflight has six metres of perimeter, and an uninsulated timber kerb punching through the roof insulation presents close to a square metre of poorly performing envelope. It costs a sheet of board and an hour, and it disappears under the covering, which is exactly why it gets skipped.

Access

Generally good. Generous plots on much of the village, off street parking, and space to stand a tower at the rear. Two storey rear slope work needs scaffold, but it can stand on private land, which avoids the highway licence that pavement scaffold requires in the older towns.

Send a photograph of the roof, one looking up in the loft, and the address so we can check the conservation and Article 4 position ourselves.

Escape windows

In a habitable loft room the roof window is usually doing two jobs, and only one of them is about daylight.

Building Regulations require a means of escape from a habitable room in a loft, and in most conversions that duty falls on a roof window. It brings a minimum clear openable area, minimum opening dimensions, and a maximum height of the bottom of the opening above the finished floor so a person can actually reach it.

The consequences catch people out. A centre pivot window is elegant and frequently unsuitable as an escape window, because the sash sits in the middle of the opening and obstructs it. A top hung unit that swings clear gives the full opening and is usually what gets specified. And setting a window high in the slope for a better view of the sky can put the opening out of reach for escape purposes.

All of that is settled at design stage rather than at order stage, because reversing it after the unit has arrived is expensive. Where an alternative escape route exists the requirement may be met elsewhere, and the roof window is then free to be chosen purely for light.

How you will actually open it

A rooflight that is awkward to open does not get opened, and a room that is never ventilated gets condensation. So this is a comfort decision rather than a luxury one.

Manual with a pole is cheapest and fine up to about two and a half metres. Above that it becomes a chore, the pole lives in a cupboard, and the window stays shut all year.

Mains electric gives a wall switch and a rain sensor. The unit premium is modest; the wiring is where the cost sits. At first fix during a conversion a cable to the rooflight position is twenty minutes. Into a finished room it means lifting flooring, chasing a wall and redecorating.

The single most common regret in this trade is fitting manual during a conversion to save the premium and wanting a motor two years later. Run a capped cable to the position at first fix even if you fit manual. It costs almost nothing and it turns a disruptive future job into a cheap one. Photograph where it is before the plasterboard goes on.

Solar carries its own panel and battery and needs no connection at all, which makes it the usual answer for retrofit into a finished loft. The panel needs daylight rather than direct sun, so it works on a north slope through an East Anglian winter. It opens more slowly, thirty to sixty seconds against fifteen to thirty, which nobody notices in use.