How much does it cost to replace a skylight?

Replacement is the moment to put right whatever was annoying about the old unit. A roof window that sits too high to reach, a handle that needs a stool, a blind that never fitted properly: all of those can change with the swap, and each change moves the price. Blinds also differ by room. A bedroom may want blackout, a kitchen or office a softer option, and a bathroom a damp-room blind, and the blind is ordered to match the unit's size code and its maker.

A manual unit opened by hand costs less than one worked by a control rod or a motor. Where the ceiling is out of reach, a rod or an electric opener answers the question of who opens it. Rain sensors are a maker's option on certain electric and solar models, closing the unit when wet, so the model matters. Cleaning counts too. A pivoting roof window brings its outside glass round to the room, which helps on a landing that is awkward to reach from outside.

A larger rooflight has more glass, a bigger frame and more flashing, so it costs more than a small one, and a heavier unit can need more hands on the roof. If the new unit fits the existing opening exactly, the roof is not cut again, and that keeps the work simple. A different size changes the timbers around the hole, so the answer depends on the measurements taken at the survey. Sizes are named by the maker's code, and a VELUX code gives the width as a letter and the height in the digits, so a code on the old unit's label is worth a photo. The page on same opening or new opening sets out the difference.

Glazing choices change the price. Solar control and self-cleaning coatings that some makers offer, and a laminated pane where the maker offers one, each add to it. Triple glazing, where a maker offers it, adds to the weight on the frame as well as to the price. The new unit should also meet the energy limits for its kind. A roof window should have a U-value no worse than 1.4 W/m²K or a Window Energy Rating of Band B or better, and a rooflight a U-value no worse than 2.2 W/m²K. Fuller figures sit in our regulations guide.

Reaching the unit safely is a cost of its own. A roof window may be changed from inside the room, while a flat roof or a high pitched roof can call for a tower or full scaffolding. The choice changes the price, and replacing a skylight without scaffolding sets out when each applies. A tight garden, a long carry or a roof edge with no safe footing all bear on it.

Flashing made for the roof covering seals a new rooflight or roof window to the surrounding roof, whether the covering is slate, concrete tile or a flat roof membrane. A flashing kit made for a tile profile differs from one for slate, so the survey notes what is on the roof. If the kerb under a flat rooflight has to be rebuilt, that adds work.

The shaft from ceiling to glass sometimes needs new lining, plaster or paint once the old unit is out. Ask at the survey how far the finishing goes. A different size of unit changes how much of the well is touched.

A photograph hides the timbers, the covering and the access, which is why the free survey comes first. No price is ever set from a picture by itself. If you want to get going, WhatsApp 07880 284133 takes pictures of the roof and the room. A fixed written quote follows the survey. The replacement skylight's fitting falls under our 10-year workmanship guarantee, given as a written document. Our cost overview covers the other products, and the same factors apply to a cost to replace a rooflight of any kind.