How much does a pitched roof skylight cost?

The price of a pitched roof skylight is not one figure, it is four stacked on top of each other. Understanding the parts is the only way to read a quote and know whether it is fair.

• The unit. A standard centre-pivot or top-hung roof window, double glazed, runs from roughly £350 for a small size up to £900 or more for a large one. Glazing upgrades, electric motors and conservation-style external finishes all sit on top of that.
• Labour. Fitting a roof window into an existing pitched roof is usually a one to two day job for two people. That covers stripping back the tiles or slates, forming the opening, fitting the unit and flashing kit, then making the covering watertight again.
• Structural work. If the window is wider than the gap between two rafters, one or more rafters have to be cut and the load carried by new timbers around the opening. This is the single biggest swing factor between a cheap job and an expensive one.
• Finishing. The inside has to be plastered, the reveal lined and often a blind fitted. This is easy to leave out of a headline price and easy to be surprised by later.

When you see a low quote and a high one for what looks like the same window, the difference is almost always sitting in the structural line and the finishing line, not in the window itself.

These are industry-general ranges for a supplied and fitted pitched roof skylight in south Essex, before any structural surprises. Treat them as a guide, not a fixed rate.

An electric window costs more than the motor alone, because it needs a power supply run to the opening and, on a rain sensor model, a little wiring at the head. If you are putting a window somewhere you cannot easily reach to open by hand, high in a loft conversion gable or over a stairwell, the electric premium usually pays for itself in daily use.

Two windows of the same size can be hundreds of pounds apart on glass alone, and on a south-facing roof that upgrade is worth every penny. Southend-on-Sea faces south across the Thames Estuary, so a rear pitch on a great many houses here catches sun from mid-morning until it swings west, with reflected light off the water adding to the load on a bright day.

Standard clear double glazing has a G-value of around 0.6, meaning it lets roughly 60 per cent of the sun’s heat energy into the room. On a north-facing pitch that free warmth is welcome and clear glass is the right, cheaper call. On a south or west-facing pitch it turns a bright room into a hot one by early afternoon. Solar-control glazing drops the G-value to around 0.3, roughly halving the heat that gets through, and typically adds £100 to £300 to a single window depending on size.

That upgrade is the one part of the specification we would never cut on a south-facing roof, and it is the reason we quote glass by orientation rather than selling the same unit to everyone. You can read the fuller argument on our page about solar-control glazing and summer overheating. The short version: on the sunny side of the house, the cheapest window is rarely the one that costs you least to live under.

The headline price is not the whole spend. These extras catch people out, so put a figure against each before you commit.

• Plastering and making good. Lining the reveal and skimming around the opening is often £150 to £400, sometimes billed separately by a plasterer rather than the installer.
• Blinds. A factory blind to match the window is £60 to £180 each. Worth having on any window you cannot shade from outside.
• Access. Most single-storey and low roofs are reached from a tower or ladders at no great cost. A high two-storey or awkward roof may need scaffolding, which can add a few hundred pounds.
• Building Control. A new or enlarged rooflight is notifiable under Building Regulations, with Part L covering thermal performance and Part K covering safety glazing. We make that notification to Southend-on-Sea City Council, or the relevant local authority, on your behalf.
• Planning. Most rooflights on a house are permitted development if they project no more than 150 mm beyond the roof plane and sit below the ridge, but conservation areas and Article 4 zones such as Leigh Cliff need a planning application. Always check with the local authority first.

None of these are large on their own. Together they can add 20 to 30 per cent to a bare install price, so it is better to see them in the quote than to meet them afterwards.

Work out three things before you ring anyone: how the roof faces, the rough opening size you want, and whether the window fits between existing rafters or needs one cut. Those three answers set most of the price, and knowing them lets you compare quotes on the same basis instead of on headline figures alone.

For a full breakdown of the parts of a job and how they add up, our pitched roof skylight installation page walks through the whole process, and the skylight installation costs page sets out ranges across every type we fit. When you are ready for a real number rather than a range, tell us the orientation and the opening size and we will come back with a glazing specification and a price. Ring 01702 898232 or request a quote, and we will look at the whole roof rather than just the hole in it.