Polystyrene Insulation Sheets UK | 25–100mm EPS Boards
Polystyrene Insulation Sheets UK | 25–100mm EPS Boards
25mm - 100mm polystyrene insulation boards.
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EPS (Expanded Polystyrene) insulation sheets in thicknesses from 25mm to 100mm. A lightweight, closed-cell rigid foam insulation for walls, floors, flat roofs, cavity fill, cold stores and general thermal insulation where cost is the primary consideration.
Used in retrofit floor insulation under screed, cavity wall insulation, flat roof warm-deck build-ups, cold store construction, packaging, void fill and any application where a cost-effective rigid insulation is needed at thicknesses where the lower thermal performance per millimetre is acceptable.
EPS vs PIR Insulation
EPS costs less per sheet than PIR but has a higher thermal conductivity (approximately 0.034 W/mK vs 0.022 W/mK for PIR). This means EPS boards need to be roughly 50% thicker than PIR to achieve the same U-value. Choose EPS where space is not constrained and cost matters most. Choose PIR where minimum thickness is important.
Available Thicknesses and Pack Sizes
25mm to 100mm in various pack sizes. Multiple sheets can be stacked for greater depths. Select from the variant options on this page.
Installation
Score with a sharp knife and snap for clean cuts. Can also be cut with a hot wire for precision edges or a handsaw. Lightweight and easy to handle. Suitable for bonding, mechanical fixing or friction-fitting depending on the application.
Frequently Asked Questions
What thicknesses of EPS insulation are available?
25mm to 100mm in the 2400x1200mm size. Multiple thicknesses can be stacked for greater insulation depth.
What is EPS insulation?
Expanded Polystyrene — a lightweight, closed-cell rigid foam insulation. Lower cost than PIR but requires greater thickness to achieve the same thermal performance.
Where is EPS insulation used?
Walls, floors (under screed), cavity fill, flat roofs, cold stores, packaging, void fill and general thermal insulation where cost is a priority over minimum thickness.
Can EPS boards be cut?
Yes. Score with a sharp knife and snap, or cut with a hot wire for clean edges. A handsaw also works but produces more dust.
What is the fire rating of EPS insulation?
Standard EPS is Class E (euroclass). Fire-retardant grades are available — check the specific product datasheet for the rating.
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FREQUENTLY ASKED QUESTIONS
1. What are EPS polystyrene insulation sheets?
EPS (Expanded Polystyrene) sheets are lightweight thermal insulation boards commonly used for walls, floors, lofts, sheds and outbuildings. They offer strong heat-retention performance while being easy to cut and install.
2. Which thickness should I choose?
25mm – Ideal for small spaces, lining walls, van insulation, or adding extra layers.
50mm – Great for sheds, garages, summerhouses and general wall insulation.
75mm – Stronger thermal performance for colder spaces or external walls.
100mm – Best for lofts, roof insulation, high-performance builds or outbuildings used year-round.
3. How many sheets come in a pack?
We offer pack sizes from 6 to 30 sheets, depending on your project size. Larger packs offer better value per sheet.
4. What size are the sheets?
Standard sheet dimensions are 1200mm × 450mm (or equivalent depending on supply). EPS sheets are designed to be easy to handle, transport and cut.
5. Are these insulation sheets moisture-resistant?
Yes. EPS naturally resists moisture, making it suitable for sheds, garages, lofts, internal walls and many outdoor building applications.
6. Can I cut the insulation myself?
Absolutely. EPS is extremely easy to cut with:
A sharp knife
A handsaw
A hot-wire cutter (optional)
This makes installation quick, even for DIY projects.
7. Can I use these sheets in a shed or outbuilding?
Yes. Polystyrene insulation is ideal for sheds, summerhouses, garden rooms, workshops and garages. It helps retain heat and reduces condensation when installed correctly.
8. Are the sheets suitable for floors or ceilings?
Yes. EPS sheets can be used for floors, ceilings and lofts, provided they are fitted against a solid substrate or between joists.
9. Do I need a vapour barrier with EPS insulation?
In most indoor applications, a vapour control layer (VCL) is recommended to reduce moisture transfer. For sheds/outbuildings, usage depends on ventilation and lining type.
10. How do I fix the sheets in place?
You can install EPS using:
Adhesive foam or construction adhesive
Mechanical fixings
Timber battens
Stapling (for lining membrane layers)
11. Are these sheets safe to use indoors?
Yes. EPS insulation is non-toxic, inert and widely used in homes, schools and commercial buildings.
12. Do the sheets help reduce heating costs?
Yes — by improving the thermal envelope, EPS insulation helps retain warmth, reduce heat loss and increase overall energy efficiency.
13. Can I layer two sheets together for extra insulation?
Yes, many customers double-layer 25mm or 50mm sheets to achieve 75mm–100mm+ performance. Ensure joints are staggered for best results.
14. Do you deliver across the UK?
Yes. We deliver nationwide across the UK, with fast dispatch and protective packaging.
MONEY BACK GUARANTEE
Here at Rackerman, we take customer satisfaction very seriously. If you are unsatisfied with the quality of your product, please email us info@rackerman.co.uk or give us a call: 01665 497513 and we will make it right.
SHIPPING
It should take no longer than 1-2 business day to process your order, then 3-5 working days (5-10 working days on RSJs + Chippings) to then receive your order from us after dispatch.
If you haven't received your items in this time frame, please contact us.
RETURNS
If you are unsatisfied with your purchase, that's completely fine! We offer a 30 day money back guarantee to all customers, no questions asked! Please contact us to arrange a return.