Slate roofs over Otley's gritstone terraces and cottages, with skylights and rooflights to match

Looking up a listed house

Historic England keeps the National Heritage List for England, and it can be searched by address. A cottage on the list carries a grade, and the grade is quoted in any application. An unlisted house next door may still sit inside a conservation area, so the two checks are separate.

What an ordinary house can expect

A house outside both designations normally goes ahead without an application, as long as the unit lies low against the slope and stays below the ridge. The permitted development conditions and the regulations behind them are set out in full on their own page.

Swapping a rooflight that is already there

A like-for-like swap reuses the existing opening, so the rafters keep their positions and only the slates round the edge are disturbed. On a listed building consent may be needed even for the swap, which means the checks above come first, and a unit with the same outline as the old one is the simpler one to put to the council. Fresh timber work is only needed if the new size differs.

Choosing a unit for a stone street

Where appearance counts, the usual pick is a conservation rooflight: a low unit in a thin dark frame that follows the roof line. The back of a terrace cannot be seen from the road, so the same unit is easier to place there.

A stairwell or a middle room generally sits under both slopes of a terrace roof, which makes the rear slope the natural first choice. It keeps the front of the row as it is, and it can make the paperwork lighter.

If the council does need to be asked, the application names one definite unit in one position, which is easier to answer than a general enquiry.

Taking the slates off without breaking them

Slate that has been on a roof for a long time is brittle at the nail holes. The slates around the position are taken up one at a time, from the top downwards, and the sound ones are stacked to go back. A slate that does break is replaced by the nearest match in size and colour.

Flashing and the courses beside the frame

Water on a slate roof is shed by the overlap of each course on the one below. The frame interrupts that pattern, so the flashing carries the water round it. Along the sides the slates are cut to lie over the edge of the flashing, and at the head they are laid so that the flow passes over the top of the kit and on down the slope.

Stacks and gable ends

A stone house usually has chimney stacks, and some have a gable end. The window needs clear slate on all four sides, and a stack or a valley can rule out a position that looks perfect from inside. Where that happens, a smaller unit a little further along the slope may do the job, or a sun tunnel can reach the room from a clearer part of the roof.

Handing the room back

Inside, the opening is lined to a splayed reveal, insulated round the frame and plastered. The finish is agreed beforehand, so the room is handed back ready for paint. An old plaster ceiling is cut with care, and the floor and stair beneath it are covered first.

Where the cold comes in

Draughts at an old frame usually trace to worn seals round the opening sash and to gaps between the frame and the roof covering. A new unit arrives with a fresh flashing, and the space around its frame is filled with insulation, so both sources are dealt with in one job.

Same opening or a little larger

Fitting into the same opening keeps the slates, the flashing line and the plaster reveal as they are. A slightly larger unit is possible if the rafters allow it, though it means lifting more slates and altering the reveal. We measure the opening first and say what the rafters permit.

Choosing a frame for an old house

The original may have been a plain painted metal frame. A conservation rooflight is its closest modern relation, with a thin dark frame that sits low enough for the slates to read as one continuous surface from the garden.

When the glass is the only problem

Where the frame is in good order and the glass has fogged between the panes, the glazed unit has lost its seal. The moisture is inside the gap, so wiping the surface does nothing. Depending on the frame, we replace just the glazed unit or the complete rooflight.

An old rooflight that opens is also worth a look. Hinges and stays wear over decades, and a new unit may open more easily and close more tightly than the one it replaces.