Frames
Steel
Steel is a strong iron and carbon alloy used for slim glazing frames, security doors and heavy frontage framing. It is much stiffer than aluminium, so sections can be very narrow, but it must be protected from rust with galvanising, primer and a paint or powder finish.
Where does it work well?
Slim-framed industrial-style frontages, heritage steel window replacements, high-security rear doors and openings that carry heavy loads, where strength matters more than weight and the budget allows for specialist fabrication.
Pros
- Very slim sightlines
- High strength and impact resistance
- Can be welded and altered
- Suits fire-rated and security doors
Cons
- Rusts if the coating is damaged
- Heavy
- Costs more to fabricate than aluminium
How long does it last?
Typically decades when the coating is kept sound, but exposed or damaged steel will rust early.
What should you check when buying?
Ask how the steel is protected, for example hot-dip galvanising to BS EN ISO 1461 before painting or powder coating. Check the weight against the structure, and ask how scratches will be repaired, especially near the coast or on busy pavements.
Common questions
Does a steel shopfront rust?
Steel rusts if its coating is broken and water gets in, so galvanising plus a sound paint system matters. Scratches, trapped water at the cill and salt exposure are the usual starting points, and should be repaired early.
Why choose steel over aluminium?
Steel gives narrower sections and greater strength, which suits slim heritage-style glazing and security doors. Aluminium is lighter, cheaper and needs less upkeep, so steel is usually picked for appearance or strength rather than cost.