What is the difference between rooflight and roof window?

Generally, ‘rooflights’ or ‘skylights’ are components installed in roofs to let daylight into a building where windows cannot be installed or are insufficiently effective. Roof windows tend to be installed in pitched slated or tiled roofs. Usually the can be opened in the same way as a window, used primarily in dwellings.

What is the difference between a rooflight and a skylight?

They are basically the same thing, however smaller individual units with transparent apertures tend to be referred to more often as ‘skylights’.

What is the difference between transparent and translucent?

No light transmitting materials allow 100% of the light to pass through due to surface reflectance and some absorption. However, with transparent materials there is usually no perceptible spreading of the light. Diffusing materials can vary in the degree in which light is scattered through them, and this gives the appearance of translucency when the image cannot be viewed in sharp focus.

What is the difference between GRP and polycarbonate rooflights?

You can find a comparison of the two materials in our GRP vs Polycarbonate sheet – to view, please click here.

What is CE Marking?

‘CE’ is the abbreviation of French phrase “Conformité Européene” which literally means ‘European Conformity’. All construction products that are covered by a harmonised European Standard must be manufactured and assessed against the Standard and carry the CE mark to be sold in Europe. This is covered by the Declaration of Performance (DoP) for that product.

What is cost balance light vs heat?

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 thermal performance of the rooflights compared to the well-insulated areas. Even with low energy LED lighting systems, this often only reduces to three times the cost. Therefore it is better to save money on lighting cost rather than heating costs. For more FAQs on design considerations, you can click here.

What is the highest non-fragility rating for a rooflight?

The test and classifications for non-fragility are detailed in a publication known as the ACR(M)001 ‘Red Book’. Broadly speaking, the highest classification for most roof assemblies will be Class B.  It is a classification for the whole roof assembly irrespective of the presence of a rooflight, so a rooflight cannot have a better classification than the roof it is fitted into.

Class A is only achievable if no element of the roof assembly is damaged during the ACR test – something that is generally only possible with roof constructions designed to resist high impact loadings such as those with concrete decks and rooflights designed for floor type loadings. For more information on this subject, check out the ‘Non-Fragility’ section of our technical manual.

At what temperature do GRP rooflights melt in a fire?

Zenon GRP rooflights are a thermoset material, rather than thermo plastic, which means that they do not soften or melt in high temperatures. They are available in a range of fire classifications to suit different applications.


Download a brochure

Download the Zenon Brochure or our comprehensive Technical Manual

Discuss spec requirements

You can contact our dedicated technical team who’ll be glad to help

Want to book a CPD seminar?

You can fill out our online booking form and select the appropriate seminar for you

Share this page on your social networks

Main logo alt
Hambleside Danelaw Limited
Long March, Daventry, Northamptonshire, NN11 4NR, UK
+44 (0) 1327 701 900   |   +44 (0) 1327 701 909

© Hambleside Danelaw Limited