Polystyrene Sheets for Insulation: Thickness, Size & Cost

How to Choose Polystyrene Sheet Thickness for Insulation Projects

Polystyrene insulation sheets range from 10mm to 100mm thick, and size and density decide how much coverage and thermal protection a project actually gets. Most buyers focus on thickness alone, but density affects compression strength just as much, and the wrong combination can leave a build under-insulated or too weak to handle the load above it.

Sheet size matters just as much as thickness. Oversized panels can be awkward to cut and position, while too many small sheets multiply the joins where heat can escape, so the format you choose affects both material cost and the finished insulation's performance.

Globe Packaging supplies EPS 70 polystyrene sheets across five size and thickness combinations, from compact packing sheets to full 2400 × 1200mm insulation panels. This lets builders and installers match the sheet to the specific job rather than compromising on whatever size happens to be in stock.

Polystyrene sheets are available in several sizes and thicknesses to suit everything from small packaging jobs to larger insulation projects. At Globe Packaging, options range from 600 × 400mm sheets for smaller applications to 2400 × 1200mm sheets for building and insulation work.

Choosing the right size can help reduce cutting, handling, and material waste. The thickness you need will also depend on the application.

1. 600 × 400 × 10mm Polystyrene Packing Sheets

600 × 400 × 10mm polystyrene sheets provide compact protection for smaller parcels,
packaging jobs, removals, and other applications.

The 600 × 400 × 10mm format is the smallest option in this range and is particularly useful when you need compact protective sheets rather than large insulation panels. The sheets are made from expanded SDN polystyrene and are mainly intended for postage and packaging, helping prevent products from moving around or becoming damaged during transit.

They can also be useful for arts and crafts projects, small building jobs, and removals, where a full-size sheet would be difficult to handle or would create unnecessary waste. Because they are supplied in a smaller format, they can be easier to cut and position for individual craft projects, products, or smaller areas.

Pricing

Globe Packaging supplies these polystyrene packing sheets in a 10-sheet pack for £6.19 (£7.43 including VAT). This makes them a practical option for businesses that need protective material for smaller parcels without purchasing larger insulation sheets.

2. 1200 × 600 × 25mm Polystyrene Sheets

1200 × 600 × 25mm EPS 70 sheets offer a versatile medium-sized format for insulation
and general building projects.

Measuring 1200 × 600 × 25mm (4ft × 2ft × 1"), these sheets provide a larger coverage area while remaining relatively easy to handle. They are EPS 70 expanded polystyrene sheets, making them suitable for a range of insulation and protective applications.

For building projects, they can be positioned between joists, beneath floor screed, or below concrete slabs. The sheets can also be used for protective packaging, such as cushioning furniture, appliances, or other larger items during removals and transport, where a larger sheet is more practical than smaller packing formats. 

The 1200 × 600mm format can be useful when you need more coverage than smaller packing sheets but do not require the larger 2400 × 1200mm panels. 

Pricing

These sheets are supplied as a 12-sheet pack priced at £40.95 (£49.14 including VAT). Buying them as a pack can provide a practical quantity for ongoing insulation, removal, or packaging work.

3. 1200 × 600 × 50mm Polystyrene Sheets

1200 × 600 × 50mm polystyrene sheets provide the same footprint as the 25mm option
with twice the thickness for projects requiring greater material depth.

If your project calls for a thicker sheet, the 1200 × 600 × 50mm (4ft × 2ft × 2") option provides the same 4ft × 2ft footprint as the 25mm sheets but with twice the thickness. This makes it a suitable option where a deeper layer of expanded polystyrene is required.

These EPS 70 sheets are suited to building applications where a thicker layer is required, including insulation between joists and beneath floor screed or concrete slabs. The additional thickness can also provide greater protection when used for packaging and removals.

The 1200 × 600mm dimensions provide a manageable sheet size, while the 50mm thickness gives you more material depth than the 25mm alternative. 

Pricing

A 6-sheet pack costs £40.95 (£49.14 including VAT). The pack contains half as many sheets as the 25mm version because each sheet uses twice the material thickness.

4. 2400 × 1200 × 25mm Polystyrene Sheets

2400 × 1200 × 25mm EPS 70 sheets provide extensive coverage for larger insulation and building projects.

For larger insulation and building projects, the 2400 × 1200 × 25mm (8ft × 4ft × 1") sheets offer substantially more coverage per sheet. The larger format can help reduce the number of individual panels required when covering bigger areas, while also providing a useful size for commercial, building, and removal applications.

These EPS 70 expanded polystyrene sheets can be installed between joists, beneath floor screed, and below concrete slabs. The large format can also be useful for removals, such as protecting furniture, appliances, worktops, or other bulky items, as well as covering larger surfaces during building and insulation projects where fewer sheets can make installation easier.

At 8ft × 4ft, these sheets are considerably larger than the 1200 × 600mm options, so they are better suited to projects where larger panels are practical to transport, cut, and install. 

Pricing

Globe Packaging sells these in a 12-sheet pack for £89.95 (£107.94 including VAT). Each sheet measures 2400 × 1200mm, giving the full pack a substantial total coverage area for larger projects.

5. 2400 × 1200 × 100mm Polystyrene Sheets

2400 × 1200 × 100mm polystyrene sheets combine a large format with substantial thickness
for projects requiring maximum coverage and a thicker insulation layer.

The 2400 × 1200 × 100mm (8ft × 4ft × 4") sheets are the thickest option in this selection. They combine the large 8ft × 4ft sheet format with 100mm of expanded polystyrene thickness, making them suitable for projects where a thicker insulation layer is required.

Like the other EPS 70 sheets, they can be used for applications including between-joist insulation, beneath floor screed, and below concrete slabs. The large format is particularly useful when substantial areas need to be covered with fewer sheets, while the 100mm thickness provides a much deeper insulation layer. 

Pricing

A 3-sheet pack costs £89.95 (£107.94 including VAT). Although the pack contains fewer sheets than the 25mm version, each sheet is four times as thick, making it a substantially thicker material option.

What Are the Polystyrene Sheet Sizes, Thicknesses and Prices? Summary Table

Match Polystyrene Sheet Thickness to the Job with Globe Packaging

Choosing the right polystyrene sheet means matching the thickness and dimensions to the job, while buying enough material to cover the required area without creating unnecessary waste. Smaller sheets suit packaging and compact jobs, while larger, thicker sheets are better suited to substantial insulation and building applications.

At Globe Packaging, we stock EPS 70 polystyrene sheets in five size and thickness combinations, from small packing sheets to full 2400 × 1200mm insulation panels. Orders over £50 qualify for free next-working-day UK Mainland delivery, with same-day dispatch before 4pm. Browse our polystyrene sheet range at Globe Packaging to find the right fit for your project. 

*Note: Product listings, prices, and delivery times shown are approximate and subject to change. Contact Globe Packaging for the latest information.