Custom RAL Rooflights: Coordinating Your Rooflight with Your Windows

Custom RAL rooflights are the specification choice that separates a coherent extension design from one that looks assembled from separate product catalogues. Custom RAL rooflights allow every aluminium element - bifold door frames, window frames, roof lanterns, and flat rooflights to share an identical powder coat colour, creating a unified metalwork palette that reads as intentional and considered.  

The modern UK extension is increasingly a coordinated metalwork project. Bifold doors, sliding doors, slimline aluminium windows, roof lanterns, and flat rooflights are all aluminium-framed products that are visible simultaneously from inside the room.  

This guide explains how to do it correctly: how to specify custom RAL colours, how to verify colour matching between different manufacturers, what to do when your bifold supplier uses a different colour system, and what lead time and cost implications to expect.  

1. How Powder Coat Colour Specification Works 

All aluminium rooflight and roof lantern frames at Skylights Roof Lanterns are powder-coated - a dry finishing process in which electrostatically charged powder pigment is applied to the aluminium extrusion and then cured in an oven at 180–200°C, creating a hard, durable coating that is integral to the surface rather than sitting on top of it. 

The colour of a powder coat is specified using the RAL Classic or RAL Design colour system - a standardised European reference system with over 200 classic colours and 1,750 design system colours, each identified by a unique numeric code. When you specify RAL 7016 Anthracite Grey, every manufacturer worldwide working to that RAL number should produce the same colour - in theory. 

The RAL number is the starting point, not the end point 

3. Dual-Colour Specification: Inside and Outside 

As covered in our roof lantern colours guide, one of the most valuable but underused features of custom RAL powder coating on aluminium glazing is dual-colour specification - a different RAL colour on the external face versus the internal face of the same frame. 

For rooflights and roof lanterns, the dual-colour approach solves a genuine design conflict: the external colour must satisfy planning requirements and complement the roof membrane, while the internal colour must integrate with the interior scheme. These requirements frequently point to different RAL numbers. 

The dual-colour option must be confirmed at the order stage - it cannot be applied retrospectively after manufacture. When ordering from Skylights Roof Lanterns, specify both the external and internal RAL colour and finish in the order notes, and request confirmation from our team that the configuration has been correctly captured before manufacture begins. 

4. Matching Rooflights to Bifold Doors: The Practical Process 

The correct sequence for achieving a matched metalwork finish across bifolds, windows, and rooflights is: 

Step 1 — Identify the bifold door RAL specification 

Ask your bifold door supplier for the exact RAL number, finish level (matte/satin/gloss), and powder coat product used on the frames. This should be available on the bifold order confirmation or the product technical datasheet. 

Step 2 — Request a powder-coated aluminium sample from your rooflight supplier 

Before placing the rooflight order, request a physical powder-coated aluminium sample in the same RAL and finish from Skylights Roof Lanterns. View it alongside the bifold frame or a bifold manufacturer's sample in the same daylight conditions and at the same viewing angle. The sample is the only reliable way to verify a visual match before committing to manufacture. 

Step 3 — Specify in writing 

Confirm the RAL number, finish level, powder coat product (if known), and any dual-colour configuration in writing on the order. Verbal RAL colour confirmations are a common source of errors on bespoke powder coat orders. A written specification creates a clear reference point if any colour discrepancy arises after delivery. 

Step 4 — Inspect on delivery before installation 

Compare the delivered rooflight or roof lantern frame directly against the bifold frame in natural daylight before installation begins. Any colour discrepancy is significantly easier and less costly to resolve before the product is installed than after. Do not install a product with a visible colour mismatch without first contacting the supplier. 

5. Lead Times and Cost Implications of Custom RAL Colours 

Standard stock colours — typically white, black, and anthracite grey — are available on shorter lead times because they are manufactured in volume. Custom RAL colours outside the standard palette require a bespoke powder coat run, which adds to both lead time and unit cost. 

For the Brett Martin Roof Lantern and Wendland Roof Lantern, custom RAL colours are available on request — contact our team on 0204 538 3079 before placing your order to confirm availability, lead time, and cost for your specific colour.