When specifying rooflights for an accessible flat roof, the key consideration is how that roof will be used over the life of the building. CWCT classifications are central to this decision, but they are often misunderstood.
CWCT Class 1 rated rooflights are designed to be non-fragile and suitable for brief standing during inspection or maintenance. They are appropriate for roofs accommodating solar panels, green roof systems, or roof-level plant, where access is occasional rather than routine.
However, while suitable for infrequent maintenance access, Class 1 rooflights are not designed for regular or day-to-day foot traffic. Where a roof forms part of a terrace, walkway, or any area intended for routine pedestrian use, a CWCT Class 0 walk-on rooflight must be specified. Class 0 units are engineered to withstand regular footfall and provide the highest level of safety for occupied roof spaces.
For self-builders and developers seeking to maximise natural light without compromising safety, CWCT Class 1 rated glass is supplied as standard across the Lunaglaze ALU flat glass rooflight range from Rooflights & Skylights.
Lunaglaze ALU combines safety with strong design and thermal performance. Tested for non-fragility, its flush, glass-to-edge appearance maintains a clean roofline, while the thermally broken aluminium frame, powder coated in Anthracite Grey (RAL 7016), achieves a combined unit U-value of 1.23 W/m²K.
Installation flexibility also supports self-build projects, with top-only or kerb-supplied options, fixed or opening variants, 14 stock sizes available within 48 hours, and a 10-year warranty as standard.
Planning takeaway
Define roof use early. Specify CWCT Class 1 rooflights for infrequent maintenance access only, and CWCT Class 0 walk-on rooflights wherever regular pedestrian use is expected. Making this distinction at design stage reduces redesign risk and supports long-term safety and compliance.