Aluminium Sheet
Metal Roofing Sheets
Where aluminium earns its price
Aluminium does not rust. It forms a thin oxide layer on contact with air, and that layer is stable and self-repairing, so a scratch does not become a corrosion line the way it does on a coated steel sheet. That single property is the whole argument for aluminium roofing.
It is specified on coastal plants, fertiliser units, chemical works and pickling shops, where salt or airborne chemicals attack steel faster than any coating can hold. On an ordinary inland shed a coated steel sheet is the cheaper answer and will last well. Near the sea or beside a process putting acid or ammonia into the air, the calculation changes.
Weight, and what it saves elsewhere
Aluminium is roughly a third the density of steel. For the same thickness a sheet weighs far less, which shows up beyond the roof itself: lighter purlins, lighter frames, easier handling on site and less crane time during erection.
The trade-off is stiffness. Aluminium is less rigid than steel of the same thickness, so the profile and the purlin spacing do more of the work. A sheet specified on thickness alone, without checking the span, will oil-can between supports.
Thickness and finish
Plain mill finish is the usual supply and is what most industrial roofs use. Where appearance matters, or where the building is visible, aluminium can also be supplied colour coated, and it then behaves like a colour coated steel sheet on the surface while keeping the aluminium substrate underneath.
Thicker sheet resists foot traffic and wind uplift better and is the safer choice on wide purlin spacing or exposed sites. Thinner sheet is common on wall cladding and short spans where nobody walks on it.
Fixings and contact with other metals
Aluminium in direct contact with dissimilar metals can corrode galvanically, and a wet roof is exactly the condition that drives it. Fasteners and flashings should be chosen to suit rather than picked from whatever is on the van, and this is the most common avoidable mistake on an aluminium roof.
The same applies to accessories. If the sheet is aluminium and the ridge and flashings are ordinary coated steel, the junction becomes the weak point, which defeats the reason for choosing aluminium in the first place.
What to send us for a quote
The covered area, the profile you want, the purlin spacing, and the thickness if the specification names one. Tell us what the building does and where it is: a coastal site or a chemical process changes what we recommend, and it is the single most useful thing you can tell us.
Frequently asked questions
Is aluminium better than colour coated steel?
For corrosion, yes, and decisively so on coastal and chemical sites. For cost and stiffness on an ordinary inland shed, coated steel is usually the better buy. It depends on where the building is and what happens inside it.
Does aluminium roofing need painting?
No. The oxide layer protects it without any coating. Colour coated aluminium is available where appearance matters, but it is a choice about looks rather than protection.
Can aluminium sheets be used with steel purlins?
Yes, this is normal. What matters is the fasteners and the flashings, which need to suit contact with aluminium so the junctions do not corrode.
What thickness should I use?
It follows the span and the exposure rather than a single standard figure. Send us the purlin spacing and the site and we will tell you what the profile needs.
Need specifications or a quote for Aluminium Sheet?