Brighouse skylights and rooflights for valley-side terraces, rear outshuts and mill-building flats

Reading the roof of the outshut

An outshut roof is either a shallow pitch carrying slate or tile, or it is flat. The covering on a flat one may be felt, EPDM or GRP, and whichever it is, the upstand dressing and weathering are worked out for that material. The new unit is joined to the old covering in the way described for a rooflight in an existing flat roof.

Flat glass or a lantern

A flat rooflight sits low on a kerb and keeps the outline of the outshut. A roof lantern stands taller, with glazing bars rising to a ridge, and gives the kitchen a ceiling of glass. Where the outshut abuts a neighbour's wall or a window of the main house, the lantern's height needs checking against both. The comparison of flat rooflights and lanterns goes into it further.

Planning for a lantern

A roof lantern usually rises past the 150mm projection that permitted development tolerates, so Calderdale Council is asked first, unless the permission for the extension itself took in the lantern. The conditions for a flat rooflight are in the guide to planning rules for roof alterations.

The light the kitchen gets

Overhead glass puts daylight on the worktops and the table instead of on one wall, and the garden doors at the back no longer have to carry the whole room. A kitchen in an outshut is usually the room the household sits in longest, so it is the room that notices the change.

On the day itself

On the day of fitting, the covering round the opening is cut back, the kerb is built up, the new unit is sealed into the roof and the ceiling lining is finished indoors, and we notify Building Control as the work requires.

The kitchen below is covered with sheets and the worktops are cleared while the roof is open. A roof that has been weathered properly leaves nothing to see from the yard except the glass.

Permission and the lease

A flat has no right to alter its roof under permitted development, which means an application to the council in the usual way. A mill may also be listed or sit in a conservation area, and either of those can bring its own consent. The lease or the managing agent will say who looks after the roof. They will also want to see the fixed quote, which covers the room being lit and the exact size of the unit.

What suits a top-floor flat

• A sun tunnel for an inner corridor or bathroom, wherever the roof sits straight above and the tube can run between the structural timbers.
• A roof window cut into the slope above a living room or bedroom.
• An electric opening rooflight where the ceiling is high enough that a manual catch would be out of reach.

Structure in a mill roof

The roof of a converted mill may be framed in trusses or large-section timbers instead of the close-set rafters of a terrace. We look at the structure from the top-floor ceiling or the roof space before choosing the size, since any change to the frame alters the structure of the roof and needs a trimmer and notification. A unit sized to sit between the members can avoid that.

Opening for air

A top-floor flat can gather warm air at the head of the room. An opening rooflight lets that air out at the press of a button on the wall or a handset, and many models include a sensor that shuts the unit at the first drops of rain. The guide to using opening rooflights for ventilation explains the uses.

Ceilings and finishes

Old mill rooms often have deep window reveals and plastered ceilings or exposed timber. Where the new opening cuts through a plastered ceiling, the lining is formed and finished to suit the room, and a sun tunnel diffuser sits flush with the ceiling so that the corridor keeps its lines.

When the cellar is under the yard

Walk-on units are flat glass panels, laminated and toughened, that the maker rates for being stood on, set level with the paving or floor above. Where a cellar extends beneath a yard, a panel there brings daylight straight down. The construction of such a panel is described under walk-on rooflights for basements.

When the cellar is under the house

If the room lies under the main rooms of the house, the floors above it stand between the cellar and the sky, and there is no sensible route for glass. In that case the answer is a change to the cellar itself, such as lighter wall finishes, and a rooflight is not on the list.

Opening the surface

The opening is cut in the slab or paving above, and the surround is formed to carry the panel and drain away from it. A panel that forms part of a roof or a floor is notifiable work like any other new opening. The points to meet are set out in the Building Regulations for walk-on rooflights.

Light on its way down

A panel in a yard only lights the part of the cellar beneath it, so its position matters more than its size. We note where the cellar walls, any steps and the main working area sit, then place the panel to reach the working end of the room. A pale ceiling and walls below carry the light further into the room.

Damp and condensation

A glass panel that daylights a cellar also sets a cold surface above a damp room, and the room should be ventilated to suit its new use. We consider ventilation along with the glass, since a bright, wet cellar is of little use as a workroom.