The short answer
Most grilles are powder-coated, with white, black and anthracite grey as common standard colours and other RAL colours to order. External grilles last longest when hot-dip galvanised before powder coating.
Which colour suits my windows?
Match the frame. White grilles almost disappear against white uPVC; black or anthracite suits grey aluminium, painted sash and period frames. A grille that matches the frame reads as part of the window rather than an addition.
What is the best finish outdoors?
Hot-dip galvanising protects steel from the inside out; powder coating over it adds colour and a second barrier. That combination is the usual choice for external grilles and gates.
Are aluminium grilles an option?
Yes, for lighter-duty internal use. Aluminium does not rust and is lighter, but steel is stronger for the same section.
How do I look after the finish?
Wash with mild detergent, avoid abrasive cleaners, and touch up any chips on external grilles promptly.
This guide is general information, not legal advice. Rules differ between England, Wales, Scotland and Northern Ireland; check with your council, building control or insurer where it matters.
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