Rooflight Replacement – Design Considerations

In a typical industrial shed building with high bay sodium lighting, the energy consumption of the artificial lighting is often around four times that of the energy lost through the reduced insulation values caused by the increased rooflight area. Even with low energy LED lighting

Most solutions involve increasing the layers within the rooflight cavity, but every layer reduces the light transmission. The Zenon Insulator product works in a different way and traps air in small transparent cells. This significantly reduces the convection currents carrying heat through the rooflight without adding more

Building Regulations Approved Document L2B that covers existing buildings other than dwellings requires rooflights to have a minimum U-value of 1.8W/m²K when assessed in the horizontal plane. The guidance given in BR443 provides for a 0.3W/m²K adjustment to a triple skin rooflight giving a 2.1W/

As a general rule, rooflights that are being replaced due to damage need only be replaced to the same standard of the damaged rooflight. Where a series of rooflights are being refurbished to improve their performance and the daylighting within the building, then they should

Where the building may only contain small areas of rooflights, such as the old ‘rule of thumb’ 10%, in most situations increasing the rooflight area can reduce the need for artificial lighting, particularly if there are areas that are gloomy and not well lit.

This method can certainly improve light transmission and reduce heat loss and condensation, however there will still be significant cold-bridging on the purlin where the rooflight remains single skin. The localised condensation may, at certain times of the year and depending upon building use, lead

No. These rooflights are supplied as a pre-assembled panel. To remove the outer skin, the whole panel would require removal.