Steps
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1.Start with the support
A sheet glued or screwed flat to a wall (a splashback) needs very little thickness, because the wall does the work. A sheet held only at its edges or at a few points has to carry itself, so it needs more.
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2.Measure the free span
The longer the unsupported span, the thicker the sheet. As a rough guide, doubling the free span needs a little under double the thickness to keep the same stiffness. A frame or a fold on the edge stiffens a thin sheet a lot.
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3.Allow for knocks and loads
If people lean on it, bump it with trolleys or kick it, go up a thickness, or move from acrylic to polycarbonate, which takes impact far better at the same thickness.
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4.Allow for heat and sun
Plastic sheet softens with heat and moves with temperature. Behind a cooktop, near heaters or in strong sun, choose the thicker option and leave room for expansion at the fixings.
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5.Check weight and handling
Acrylic weighs about 1.2 kg per square metre per millimetre of thickness, so a full 2440 x 1220 mm sheet of 6 mm acrylic is roughly 21 kg. Thick sheets need two people to handle and stronger fixings.
Tips
- Make a cardboard mock-up at full size to check the look before you order.
- A thinner sheet in a frame is often cheaper and stiffer than a thicker unframed sheet.
- Keep the protective film on until installation to avoid scratches.
Typical thicknesses by job
Kitchen and bathroom splashbacks, fully backed: 4 to 6 mm acrylic. Sneeze guards and counter screens: 4 to 6 mm acrylic, or 4 to 5 mm polycarbonate where they may be hit. Brochure holders and small point of sale: 1.5 to 3 mm PETG or acrylic. Flat signs fixed on stand-offs: 3 to 6 mm acrylic, or 3 to 5 mm ACM for outdoor panels. Display cases and cabinets: 4 to 6 mm acrylic for small cases, 8 to 10 mm for larger ones. Picture frame glazing: 2 to 3 mm acrylic. Secondary glazing and window inserts: 3 to 6 mm acrylic or polycarbonate. Machine guards: 4 to 6 mm polycarbonate. Wall cladding and hygienic linings: 2 to 5 mm PVC. Cutting boards: 10 to 20 mm HDPE.
Acrylic and polycarbonate are not interchangeable at the same thickness
Acrylic is stiffer, so for the same thickness it sags less across a span and looks flatter. Polycarbonate is far tougher and will flex rather than crack. That means a polycarbonate panel can often be thinner than acrylic where impact is the worry, but slightly thicker where stiffness and flatness matter. If you are not sure, tell us the job and the size when you request a quote and we will suggest a thickness.
Sheet sizes
Full sheets of acrylic, polycarbonate, PETG, PVC and ACM are commonly 2440 x 1220 mm, with some materials and thicknesses also available in larger sizes. Planning your panels around the full sheet keeps offcuts and cost down. Need a sheet cut down? Cutting is available on certain materials at certain depots. Request a quote with the sizes you need and we'll confirm.