How much does a roof lantern cost?

Picture a glass box with sloping sides, standing over an opening cut in a flat roof. That is a lantern, and it is made to measure far more often than a roof window is, which shows in the price. The footprint is the first factor, because a lantern a metre across and one three metres long are different objects to build, carry and glaze. The pitch of the glazing and the number of panes follow from that, and each extra bar or corner adds fabrication time before anyone reaches your house.

The frame material and finish come next. Aluminium and timber frames are priced differently, as are colours inside and out, and any opening vents or electric controls. The glass matters as well, since the Building Regulations class a lantern as a rooflight, which has to meet a heat-loss limit. Our guide to roof lanterns, installation and replacement describes each part, so you can judge what a supplier's price covers.

Many lantern bills grow here. A lantern stands on an upstand, a low wall or kerb around the opening, and the waterproof covering of the flat roof is dressed up and over it. If that covering is worn, the sensible moment to renew it is while the roof is open. Checkatrade's replacement guide, in a table marked as plus VAT and dated October 2026, gives £2,800 to £7,500 for a flat roof. That range covers a whole roof, not a lantern, but it shows what is at stake if the roof under yours is spent.

With a sound covering the job shrinks. Less, in figures updated in March 2026, puts small flat roof repairs at £150 to £500. Our survey checks the roof before anything else and gives you a plain answer on whether the lantern can go onto what is there. A lantern on a tired covering is the usual reason for a leak a few winters on, which our answer on why a roof lantern leaks covers.

Lanterns are heavy for their size, and glass cannot be dropped or dragged. Getting one onto the roof can need extra hands, a lifting arrangement or scaffold with a working platform, and that is a cost separate from the lantern. Checkatrade's scaffolding table, dated October 2026, shows around £800 a month for a terrace, £875 for a semi, £1,000 for a detached bungalow and £1,200 for a detached house.

The same table puts a chimney-height scaffold at £660 a week, which hints at how quickly time on the frame adds up. A lantern fitted to a rear extension that can be reached from the garden may cost less to reach than one above a two-storey house. Day rates are another input. Checkatrade's repair guide, in a table dated June 2026, gives £280 to £360 a day for roofers, and the days needed rise with a larger opening, or when the structure must be altered first.

Under Approved Document L, a rooflight in an existing home should reach a U-value of 2.2, and an upstand built on site 0.35. U-value is a measure of heat loss, and a lower figure is better. Those limits apply until 24 March 2027, after which the 2026 edition carries identical values for rooflights. A cheaper lantern that cannot show the rating is a false saving.

A lantern is also taller than a roof window, and that raises a planning question. Permitted development for roof alterations on a house stops where a unit protrudes more than 0.15 metres beyond the roof plane, so a lantern on a house may need an application. Flats, listed buildings and conservation areas add their own checks, set out in our skylight planning guide. Forming a fresh opening in a roof is a structural alteration, so building control is involved too, and the quote should say who deals with it.

Ask every supplier what the total contains. Is VAT in the total? Gov.uk gives the standard rate as 20 per cent. Is the upstand built by the supplier or by the roofer, and who is responsible where the two meet? Does the price cover renewing the flat roof covering around the lantern, or only the lantern?

Those answers explain most differences between totals. A low figure for the glazed unit alone is not a price for the job, and a higher figure that includes the covering, the upstand and the making good inside may be the better value once the missing work has been added to the cheaper one. We send photographs of your roof after the survey, followed by a written quote at one overall price. If a lantern is wrong for the roof, we will tell you, and the rest of our skylights and roof windows work shows what else could suit it.