Perforated Metal Sheets

Three perforated metal sheets on a white background showing mild steel, galvanised steel and aluminium finishes with round hole patterns in varying sizes

Perforated metal sheets with round hole patterns in mild steel, galvanised steel and aluminium, supplied in standard sheet sizes from UK stock. The range covers hole diameters from 0.8mm up to 20mm across more than 40 pattern and material combinations, with open areas from around 23% to over 50%, so there is a sheet to suit most screening, ventilation, guarding and decorative jobs.

Perforated metal sheets with round hole patterns in mild steel, galvanised steel and aluminium, supplied in standard sheet sizes from UK stock. The range covers hole diameters from 0.8mm up to 20mm across more than 40 pattern and material combinations, with open areas from around 23% to over 50%, so there is a sheet to suit most screening, ventilation, guarding and decorative jobs.

Common applications include machine guards, radiator covers, speaker grilles, architectural screens, balcony infill panels, trailer floors and side panels, vehicle bodywork, ventilation panels, sign-board backing and decorative interior cladding. Material choice depends on whether the sheet will be exposed to weather, whether weight matters, and whether the sheet will be painted or left as-is.

How Perforated Sheet is Specified

Every perforated sheet is described by an R/T pattern code. R is the hole diameter in millimetres and T is the pitch — the centre-to-centre distance between adjacent holes. For example, R5/T7 means 5.0mm round holes at 7.0mm pitch. All patterns in this range use a staggered 60-degree triangular layout, which is the standard arrangement for round-hole perforated sheet because it gives the best balance of open area and material strength. The combination of hole size and pitch determines the open area — the percentage of the sheet surface that is open hole.

Materials Available

Three materials cover the range. Each suits different environments, budgets and finishing requirements:

  • Mild steel — the widest pattern selection (30 patterns), lowest cost per sheet, strongest for a given thickness, but no corrosion protection as supplied. Suited to indoor use or jobs where the sheet will be primed and painted. Manufactured to BS EN 10025-2.
  • Galvanised steel — pre-galvanised mild steel with a zinc coating applied before perforation. Gives outdoor corrosion resistance without painting, at a moderate cost premium over bare mild steel. Nine patterns available. Manufactured to BS EN 10346.
  • Aluminium — around one-third the weight of steel, naturally corrosion-resistant (no coating needed), and easy to cut and form. Costs more per sheet than mild steel but saves on handling, transport and finishing. Five patterns available in mill finish.

Mild Steel Perforated Sheet

The mild steel range is the largest, with 30 patterns covering hole sizes from 0.8mm to 20mm and thicknesses from 0.5mm to 5mm. Sheet sizes are 2 x 1m and 2.5 x 1.25m depending on pattern. Mild steel gives the highest strength for a given thickness and the lowest sheet cost, making it the default choice for machine guards, structural screens and any application where the sheet will be painted or powder coated after fitting. The trade-off is that bare mild steel has no corrosion protection, so it needs finishing for outdoor or damp environments. Steel grade is S235 to BS EN 10025-2.

Galvanised Steel Perforated Sheet

Galvanised perforated sheet uses pre-galvanised mild steel — the zinc coating is applied to the coil before the sheet is perforated and cut. This gives corrosion resistance for outdoor, agricultural and industrial applications without separate painting or galvanising. Nine patterns are stocked, covering the most common hole sizes from 2mm to 20mm in thicknesses from 0.8mm to 2mm. The zinc finish is a dull silver and can be left exposed or overcoated. Manufactured to BS EN 10346. Galvanised sheet typically costs 20-40% more than the equivalent mild steel pattern.

Aluminium Perforated Sheet

Five aluminium patterns are available in hole sizes from 3mm to 10mm, all at 1mm or 1.5mm thickness in mill finish. Aluminium weighs roughly a third of steel for the same sheet dimensions, which makes a significant difference on large panels, overhead installations and vehicle or trailer work where every kilogramme counts. The natural oxide layer protects against corrosion without any coating, so aluminium perforated sheet can be used outdoors with no further finishing. The mill finish suits architectural and decorative work. The trade-offs are lower strength than mild steel and a higher cost per sheet.

Open Area and What It Means

Open area is the percentage of the sheet surface that is hole rather than solid material. A higher open area means more airflow, more light transmission and less weight, but also less structural strength and rigidity. A lower open area gives a stronger, stiffer sheet with less visual transparency. Open areas in this range run from around 23% (the tighter patterns like R3/T6) up to around 53% (the more open patterns like R10/T13). Choosing the right open area depends on the job — ventilation panels and speaker grilles often need high open area, while machine guards and structural screens need more solid material.

Standard Sheet Sizes

Sheets are supplied in two standard sizes depending on the pattern: 2 x 1m and 2.5 x 1.25m. These are fixed manufacturing sizes. Perforated sheets are not available cut to size — order the standard size and trim on site if needed. Mild steel and galvanised steel can be cut with a jigsaw, nibbler or angle grinder with an appropriate disc. Aluminium cuts cleanly with standard metalworking tools.

Common Applications

Perforated sheet is used wherever you need a combination of airflow, visibility, drainage, or screening with structural support. Typical jobs include machine and equipment guards, radiator and heater covers, speaker and audio grilles, architectural cladding and decorative facades, balcony and staircase infill panels, trailer floors and vehicle body panels, agricultural screens and drying floors, sign-board backing, security screens, and ventilation panels in plant rooms and enclosures. Finer patterns (sub-3mm holes) suit decorative and acoustic work; larger holes (8mm and above) suit guarding, drainage and heavy screening.

Choosing the Right Material

Use mild steel for dry indoor work, anything that will be painted or powder coated, and applications where maximum strength matters more than corrosion resistance — it is the cheapest option and the widest range. Use galvanised steel for outdoor, damp, or unheated environments where you want corrosion resistance without the cost and weight saving of aluminium. Use aluminium where weight matters (vehicle and trailer work, overhead panels, large facade runs), where natural corrosion resistance is needed with no coating, or where the natural mill finish suits the look.

Delivery Information

Perforated metal sheets are delivered on a pallet to mainland UK addresses with a lead time of 3-5 working days. Aluminium sheets are lighter than steel, so handling on arrival is easier, but all perforated sheet deliveries are pallet-sized and require suitable site access for the delivery vehicle.

Bulk Orders

Trade and project pricing is available on orders of five or more sheets, multi-pattern orders, or full-project supply across materials. Contact us with the patterns, quantities and any specific requirements for a quote.

FAQ

What does the R/T pattern code mean on perforated sheet?

R is the hole diameter in millimetres and T is the pitch, which is the centre-to-centre spacing between adjacent holes. R5/T8 means 5.0mm round holes spaced at 8.0mm pitch. All patterns use a staggered 60-degree triangular layout. The ratio of hole size to pitch determines the open area of the sheet.

Should I choose mild steel, galvanised or aluminium?

Mild steel is cheapest and strongest but has no corrosion protection, so it suits indoor work or sheets that will be painted. Galvanised steel has a zinc coating for outdoor corrosion resistance at a 20-40% premium over mild steel. Aluminium weighs roughly a third of steel, resists corrosion naturally without coating, and suits vehicle, trailer and architectural work, but costs more per sheet and is not as strong.

Can perforated metal sheets be cut to size?

Sheets are supplied in standard sizes only — 2 x 1m or 2.5 x 1.25m depending on pattern. They are not available cut to size from Rackerman. You can trim perforated sheet on site using a jigsaw, nibbler or angle grinder with a suitable cutting disc.

What open area do I need?

It depends on the application. Higher open area (40-50%+) gives maximum airflow, light and drainage but less strength — suited to ventilation, speaker grilles and decorative screening. Lower open area (23-35%) gives a stronger, stiffer sheet with less visual transparency — better for guards, structural screens and applications where rigidity matters. The open area is set by the pattern code: tighter pitch relative to hole size means lower open area.

How are perforated sheets delivered?

Sheets are delivered on a pallet to mainland UK addresses within 3-5 working days. Aluminium is lighter than steel so offloading is easier, but all deliveries are pallet-sized and need suitable access for the delivery vehicle.