Choose for the room, not just the glass colour.
Glazing choices affect how an opening looks and performs. Begin with the room’s purpose, roof orientation, privacy needs and the times of day when glare would be unwelcome. Tell us whether a view of the sky matters or whether a more diffuse appearance is preferable.
Separate the performance questions.
| Question | What to ask for |
|---|---|
| How much daylight? | Visible light transmission for the specified glazing; discuss glare and room orientation. |
| How much solar heat? | Solar heat gain information for the selected glass and system, assessed with the building design. |
| How well does it insulate? | Relevant U-value information, clearly distinguishing glass-only from whole-system performance. |
| What glass is supplied? | Glazing build-up, thicknesses, coatings and applicable safety-glazing requirements. |
| What covers this product? | Current documentation identifying the actual model, dimensions, geometry, finish and installation conditions. |
Double glazing is one part of the specification.
The glass, frame and installation all matter. Do not assume every double-glazed product has identical thermal performance or that a tinted pane resolves every heat or glare concern. Ask your designer to assess the complete room and building where energy performance is part of the brief.
Product certification must match the product.
Some documents apply only to particular systems, shapes, finishes and mounting conditions. Skydoors and bespoke shapes should not be assumed covered by documentation for a rectangular Roof Window. Ask for current, applicable manufacturer documents and have project-specific requirements reviewed by the relevant professionals.
The historical certificate currently linked below lists exclusions and an expiry date of 24 August 2026. We do not use it as evidence of current certification. Current documentation must be requested for the selected proposal.
Historical Atlite certificate (PDF; expired August 2026) (opens a new tab)Resolve the roof and internal connections.
Confirm roof pitch, covering, structural opening, mounting, drainage and flashing against the installation instructions. Include the lightwell and internal finish on a section. Agree which trade owns each part of the work; a product brochure does not define your complete installation scope.
Keep these records at handover.
- Final product identification and agreed drawings
- Glazing and system documentation applicable to the supplied unit
- Installation and care instructions
- Operating equipment and backup instructions where relevant
- Product warranty terms and installation responsibilities
See our architect and builder resources and quote comparison guide for the rest of the brief.