Rooflights and Roof Domes

Roof domes (also called polycarbonate domes or rooflight domes) are a type of rooflight designed to allow natural light into a building. They are typically made from polycarbonate and are commonly used on flat or low-pitched roofs in both commercial and residential buildings.

In the UK, roof ventilation regulations—set out in Approved Document C and BS 5250—are designed to prevent condensation and moisture buildup. They require a minimum 50mm air gap between the insulation and roof underlay, along with continuous ventilation at both the eaves and higher levels.

Flat roof windows are known as skylights. The terms skylight and rooflight are often used interchangeably. There is no real difference, people may just use different language based on their location.

While both bring natural light, Flat roof light domes and skylights differ in design, material, and application.

Roof Dome

• Shape: Curved (dome-shaped)
• Material: Polycarbonate or acrylic (lightweight, impact-resistant, 200x stronger than glass)
• Best For: Flat or low-pitched roofs (commercial, industrial, residential)
• Installation: Mounted onto a kerb or upstand
• Ventilation: Fixed or opening (AOVs for smoke control)
• Example: Coxdome Polycarbonate Domes

Skylight

• Shape: Flat or slightly curved
• Material: Glass with aluminum or uPVC frame (heavy, superior insulation & clarity)
• Best For: Pitched and flat roofs (modern homes, commercial buildings)
• Installation: Often integrated into roof structure
• Ventilation: Fixed or operable
• Example: Flat Glass Skylights or Roof Windows

Which to Choose?

• Durability & Affordability: Roof dome

Aesthetics & Premium Insulation: Skylight

A typical rooflight, depending on its quality and maintenance, will last between 20 to 30 years. However, we do offer 10 years warranty on our rooflights.

The most effective roof venting system will depend on the building design (height and layout), the climate and roof type.