Skylights and rooflights for stone terraces on the valley sides in Marsden and the Colne Valley

What sits above a bank-side room

Usually a back room below the stair is under a lean-to or an outrigger, and a bedroom is over the top of the main block. A lean-to roof is low and shallow. A pitched window or a flat rooflight set into it lights the room below, and the stone wall of the house stands behind the flashing.

Reaching the lean-to roof

On a terrace set into a slope, the ground at the back can rise high up the wall. That can put the lean-to roof within reach and leave the front of the house as the awkward side. A roof on a steep street may call for scaffold on the front, or a working platform on the back, so access is looked at before the quote is written, and the price in that quote is fixed.

Choosing the unit for a lean-to

A flat roof rooflight suits a shallow lean-to that is close to level. A pitched lean-to takes a roof window in the slope instead. Whichever it is, the kerb or frame sits clear of the wall, with a gutter detail where the roof meets the stone. Fitting into a covering that already exists is described in cutting a rooflight into a roof that is already laid.

Light and damp together

Stone walls built against a bank hold the cold as well as the moisture.

A room against the bank can also be a damp one, and a rooflight does not cure that. Daylight and an opening unit help a room dry out, and the opening in the roof gives air a way to leave. Damp from the bank needs a separate answer from a builder.

Window sizes against the slope

Before choosing, we measure the width between rafters inside the outrigger, because those rafters set the biggest window that can go in without cutting any of them.

A lean-to has little height to give, so a tall frame would meet the wall flashing at an awkward angle. A broad, short unit sits more naturally on a low pitch and lights more of the floor. The width is then limited by the rafters, which in an older outrigger can be uneven.

Kirklees Council answers planning questions for Marsden, and our planning guide for rooflights on houses sets out the usual limits.

Three questions for the council

• Does the street lie inside a conservation area, and is it covered by an Article 4 direction? That direction withdraws the usual allowance for rooflights.
• Is the house listed? Listing means the council must consent to a new rooflight, whatever the general rules say.
• Is it a house, or has it been divided? Flats and maisonettes sit outside the roof-alteration allowance altogether, which means an application.

The council can also say whether a unit that replaces one already in the roof needs anything. Swapping a unit in the opening it fills disturbs the roof less than forming a new opening, although listing brings its own consent rules.

An ordinary house

A terrace that is unlisted and outside any protected area follows the general rules, as it would anywhere else in England.

Away from those cases, a house can normally add a rooflight without an application when the frame rises no more than 150mm above the slope and stays under the ridge. A window facing the side must be obscure and fixed below 1.7m above the floor. Every condition is laid out in the planning guide.

What the pavement sees of the slope

A unit on the back slope cannot be seen from the lane. One on the front slope sits in the line of the street, and a row of them reads as a pattern. In a protected street, a single conservation rooflight at the back is easier to put forward than several at the front.

Replacing in a listed or protected house

The same questions apply to a replacement. A like-for-like unit in a protected street may be received more easily when it matches what is there, in frame colour, bar pattern and the way it sits against the slates. Photographs of the existing rooflight help the conversation with the council.

Taking a definite unit to the council

A council can respond to a defined unit better than to a loose idea. The quote gives you the room and the size of the unit, which is the detail they ask for. The conservation rooflight design guide shows what the slim frame looks like against stone slate.

Why wiping does nothing

Anyone who has tried knows the cloud is still there after the glass has been cleaned.

The moisture is inside the gap, so neither side of the glass can be reached. A sealed unit that has let in damp air will go on misting. The guide to why rooflight glass mists goes through how the seal fails.

Glass only, or the whole unit

If the frame has stayed sound and the flashing still sits tight, we can fit a new sealed unit into the frame you have. If the frame is corroded, rotted or a poor fit, the whole rooflight comes out. A straight swap uses the same opening. A larger unit enlarges the opening and changes how the roof is carried, which is covered in fitting a bigger rooflight in place of an old one.

What a new unit brings

An old rooflight tells you roughly when it was installed. A frame from some decades back has no thermal break and thin glazing, and both can show up as a cold stripe on the ceiling in winter.

An old unit may be single-glazed or an early double-glazed one. A new sealed unit has a low-emissivity coating and a warm-edge spacer, and loses less heat. The section on misted rooflight replacement lays out the options.

The flashing around it

Flashing is the thin metal that carries water round the frame and out over the slates or stone below it.

On an old slate or stone roof, the flashing around a worn rooflight is often as tired as the glass. We look at it when the old unit comes out, because a new unit set in a failing flashing leaks at the edge.

Fitting the new one to stone slate

If the roof is stone slate, the courses beside the opening are lifted in order and put back to lap the new flashing. Because the stone is heavy, the old rooflight may have sunk a little into its bed. The new frame is levelled before the slates return.