Dome Rooflights: Complete Guide in Cheltenham

A dome rooflight is a raised, curved skylight set into a flat or low-pitch roof, shaped to shed rain and snow and to spread daylight evenly into the room below. They have long been a practical, hard-wearing way to bring light into Cheltenham homes, extensions, outbuildings and commercial roofs — and modern domes are a world away from the yellowing plastic bubbles of decades past. If yours is dated, leaking or misting, a full replacement is the lasting fix.

At Aspect Skylights, we install and fully replace dome rooflights across Cheltenham and the wider Gloucestershire area. We do not repair, so where an old dome is past its best, our focus is a clean, modern unit fitted correctly on a sound kerb. This guide explains what dome rooflights are, when they suit a project, the options available, and what to expect on cost — so you can decide with confidence before booking a free survey.

What is a dome rooflight?

A dome rooflight is exactly what it sounds like: a domed, curved transparent or translucent panel raised above the roof line on an upstand or kerb. The curve does two useful things. It sheds water and debris rather than letting them pool, and it gathers and diffuses daylight across a wider arc than a flat pane, so the light reaches further into the room. Domes are most common on flat roofs — rear extensions, garages, utility rooms, porches, outbuildings and flat-roofed commercial buildings — where their self-draining shape is a real advantage.

Traditionally, domes were made from polycarbonate or acrylic in a single or double skin. Today you can also choose glass dome and curved-glass alternatives that look far more refined. The classic dome remains popular where durability, value and a self-cleaning curve matter more than a flush, contemporary line.

When a dome rooflight is the right choice

A dome suits a number of situations particularly well:

• Flat and low-pitch roofs where standing water would be a concern with a flat pane — the curve drains naturally.
• Outbuildings, garages and utility rooms where a tough, cost-effective, low-maintenance rooflight is ideal.
• Commercial and industrial roofs across Gloucestershire, where domes have been a workhorse for daylighting warehouses and units for years.
• Replacing a like-for-like dome on a property where the existing kerb and opening already suit a domed unit.
• Snow-prone or exposed roofs in the higher Cotswold villages, where a shedding curve copes well with weather.

If you want the slimmest, flush, architectural look of a modern flat rooflight instead, our flat-roof skylight installation page covers that alternative. Both sit on a kerb; the difference is the profile and the finish.

Dome options and how they work

Polycarbonate and acrylic domes

The traditional choice. Lightweight, shatter-resistant and economical, polycarbonate and acrylic domes are available in clear, opal (diffused) and tinted finishes. Opal domes spread a soft, even light and hide the view of the sky, which suits utility rooms, bathrooms and commercial spaces. Multi-skin versions improve insulation. Our plastic and polycarbonate skylight installation page covers these materials in full.

Glass and curved-glass domes

For homes where appearance matters, a glass dome or low-profile curved-glass unit gives a clearer, more premium finish that resists scratching and yellowing far better than plastic. If you like the curved profile but want the refinement of glass, our curved glass rooflights guide is the natural next read.

Fixed or opening

Most domes are fixed, but opening and ventilating versions are available where you want to clear warm or moist air — useful in a kitchen, utility or commercial space. Manual, electric and solar-powered openers all exist.

Single, double and triple skin

The number of skins or panes drives the insulation. A single-skin dome is the most basic; double and triple-skin polycarbonate, or double and triple-glazed glass, hold heat far better. For a heated room, a well-insulated multi-skin or glazed dome is worth the small extra cost. See our energy-efficient skylight installation page for the thermal side.

Suitability: is a dome right for your roof?

Domes need a flat or low-pitch roof and a sound kerb to sit on. The kerb, or upstand, lifts the dome above the roof surface so water drains cleanly to the sides — the same principle behind any well-installed flat-roof rooflight. If your existing roof already has a dome, the opening and kerb are usually already sized for a replacement, which keeps the job straightforward. On a new opening, we assess the structure, the roof covering — felt, EPDM, GRP or single-ply — and the joists at survey before quoting.

Domes are less suited to steeply pitched roofs, where a roof window or pitched rooflight is the right product. Our pitched-roof skylight installation page covers those.

Glazing, insulation and Building Regulations

Whatever the material, a dome serving a heated room should meet the thermal performance expected under Building Regulations for replacement glazing. In practice that means a well-insulated multi-skin or double or triple-glazed unit rather than a thin single skin. A modern, properly specified dome keeps heat in, reduces the cold surface that condensation forms on, and feels far more comfortable than the draughty old units many domes replace.

Safety and impact resistance matter too, especially on commercial roofs or anywhere the dome could be walked near during maintenance. Polycarbonate is inherently impact-resistant; glass domes use toughened or laminated panes. We specify the right glazing for the location and use as part of the survey.

Indicative cost of a dome rooflight

As a rough 2026 guide for supply and installation in the Cheltenham and Gloucestershire area:

• Small polycarbonate dome (e.g. utility, porch, garage): from around £700–£1,400 installed.
• Mid-size opal or double-skin dome: roughly £1,200–£2,200 installed.
• Glass or curved-glass dome: from around £1,800–£3,500+ depending on size and glazing.
• Opening or electric dome: add roughly £400–£900 for the mechanism.

These figures are indicative only. The kerb condition, roof covering, access and whether it is a like-for-like replacement or a new opening all affect the price. Every job is confirmed with a fixed written quote after a free survey — no guesswork, no surprises.

A local note for Cheltenham and Gloucestershire

Dome rooflights are a familiar sight on Cheltenham’s flat-roofed extensions, 1960s and 70s homes, garages and the commercial units around Lansdown, Charlton Kings and the industrial estates toward Gloucester. Many of these original domes are now decades old — yellowed, brittle, single-skin and prone to condensation. A modern replacement transforms both the light and the warmth of the room beneath. In the more exposed Cotswold villages, the self-shedding curve of a dome continues to earn its place against wind, rain and the occasional snowfall.

Next steps

If your dome is dated, leaking or misting, or you want to bring daylight into a flat-roofed space, a full replacement or new installation is the lasting answer. We will assess your roof, kerb and the room beneath, then recommend the right dome — or a flat or curved-glass alternative if that suits you better — and give you a clear, fixed written quote.

Explore our flat-roof skylight installation and curved glass rooflight options, browse all our services, then get a quote. We will recommend the right unit and give you a fixed written quote after a free survey, backed by our written guarantee on our workmanship.