Flat roof rooflights in Newcastle upon Tyne

A flat roof is often the one part of a home with nothing built on it, which makes it the easiest place to bring daylight in. Light from above travels further into a room than light from the side, so a deep kitchen or a windowless hall can end up brighter from one opening overhead than from a new wall window.

Brightness where the walls cannot help

On a Tyneside terrace, the rear kitchen is often a long, narrow room with its only window at the far end. A rooflight over the middle of it lights the worktops, the table and the corridor between them. The same goes for a downstairs flat whose back offshoot has a flat roof, or an inter-war semi with a rear extension that has gone dim.

Natural light is more than a pleasant extra. A room that gets proper daylight reads as bigger, and people tend to spend more time in it. That is a matter of how the space feels, and it is the reason a rooflight is often chosen before a bigger window.

Which rooms it suits

The usual candidates are a kitchen or kitchen-diner in an extension, a utility room, a bathroom with no outside wall, a stairwell, and a bedroom or study built into a flat-roofed loft or garage conversion. A converted garage is a good example: the roof is flat, the front is often a blank door or brick, and a rooflight gives the new room the daylight it never had.

Light is not the only benefit

A unit that opens adds ventilation. Warm air gathers at the highest point of a room, and a vent there lets it out, with fresh air drawn in through a door or window lower down. In a kitchen that helps with steam and cooking smells. Glazing also adds heat from the sun on bright days, which is why the survey looks at which way the roof faces before the glass is chosen.

Daylight and the look of the extension

Outside, a flat rooflight sits quietly on the roof and does not change the outline of the house. Inside, the shaft or splay beneath it can be finished in white so the light spreads across the ceiling and down the walls. For a garden-facing kitchen extension, this brings the daylight deep into the plan without losing wall space for units.

The rest of this page goes through each decision in order. If you are still weighing a flat rooflight against a taller glazed roof, our page on roof lantern installation sets out where a lantern makes more sense.

A flat rooflight does not sit on the roof so much as stand on a small frame built up from it. That frame, called an upstand or a kerb, raises the glass above the water that runs across the roof and keeps the weather out of the joint.

Why the upstand matters

Manufacturers set minimum upstand heights, commonly around 150mm above the finished roof. A lower upstand lets rain splash or pond against the joint, and snow can bank against it. The upstand is also lined with insulation, so that the cold roof edge does not become a spot where moisture gathers inside. Our explainer on flat rooflight upstands and kerbs shows how they are built.

The kerb can be timber covered with the roofing membrane, or a prefabricated insulated upstand supplied with the rooflight. Which suits depends on the roof build-up and the unit, and the quote says which is allowed for.

Fall and drainage

A flat roof is not truly flat. It is laid with a gentle slope, called a fall, so water finds its way to a gutter or outlet. A rooflight is a block in that path, so the water has to be steered round it. We read the fall around your opening at the survey. If the roof ponds water, the covering may need to be reworked as part of the job. Our answer on what fall a flat rooflight needs deals with it.

Structure and the opening

The opening interrupts the roof joists, so the ones that are cut need to be carried on new framing around the hole. The size of the opening and the direction the joists run decide how much framing is needed. Loft and ceiling space below matter too: a rooflight needs a lined shaft or splay from the opening down to the ceiling line, which also spreads the light into the room.

Weatherproof by detail, not by sealant

A watertight rooflight depends on how the upstand, the membrane and the flashing are put together, not on a bead of sealant. The membrane is dressed up the upstand and under the rooflight's own cover, so that water running down the roof reaches the covering below and cannot slip behind.

People type "how much does a flat roof skylight cost" into a search box and want a number. We do not put figures on web pages, because two openings on the same street can differ widely. Expect a survey first and a fixed written quote after it.

What raises or lowers a price

The biggest factor is the size and type of the unit. A larger opening needs a bigger piece of glass, more framing and a bigger upstand. An opening unit with an electric motor costs more than a fixed one. Glass specification also counts: triple glazing and solar control add to the cost of a pane.

The roof around it

Sometimes the roof, not the rooflight, drives the cost. A sound roof with good drainage is simple to work with. A tired covering, ponding or a damaged deck is better dealt with while the roof is open than later, and that work goes in the quote as a separate line. Access plays a part too, as does the height of the ceiling below and the state of the space under the opening.

How the quote works

After the free survey we write a fixed quote. The figure holds unless the job itself alters, so you know what you are signing. It covers the unit, the upstand, the roof work, the finishing inside, and the Building Control notification where the work is notifiable. The finished work is covered by our written 10-year workmanship guarantee. Our page on skylight and rooflight costs explains each cost driver at greater length.