Short answer: choose expanded cork board (ICB) thickness from your project's required thermal resistance, the documented properties of the selected board and the space available. CorkMart supplies 1000 × 500 mm boards in thicknesses from 10 to 150 mm. No single thickness is suitable for every wall, roof, floor or cold room.
How to calculate the thickness you need
Thermal resistance is thickness divided by thermal conductivity: R = d / λ. To find thickness for a target R, use d = R × λ. Use d in metres and the thermal conductivity declared for the exact product reference you intend to purchase.
The U-value of the complete wall, roof or floor also depends on the other layers, fixings and construction details. Ask your project designer to confirm the target and complete build-up. Do not use a generic conductivity value or a table for a different board as the product's declared performance.
Available sizes and quantities
Each board measures 1000 × 500 mm and covers 0.5 m². Available thicknesses are 10, 15, 20, 25, 30, 35, 40, 50, 60, 75, 80, 100, 125 and 150 mm.
- 1 board — 0.5 m².
- Pack 5 m² — 10 boards.
- Pack 10 m² — 20 boards.
- Pack 25 m² — 50 boards.
Choose the board for the complete construction
Thickness alone does not establish suitability. For walls and façades, check the fixing and finish system; for roofs, check moisture control and waterproofing; for floors, check load resistance, screed and any underfloor heating. Cold rooms and vibration-control projects require a specification for the particular operating conditions.
Confirm the manufacturer's product reference and applicable technical documentation before ordering if your project requires particular thermal, fire, moisture or load performance.
Check the build-up height
On floors, allow for the screed, finish and any heating pipes; on walls, allow for adhesive, fixings, render or plasterboard. Check door thresholds, window reveals and existing finishes before choosing a thicker board.
Plan quantity, handling and delivery
Divide the area by 0.5 m² to get the number of boards, then add an allowance for cuts. Thickness affects package volume and weight, so confirm handling and delivery requirements for the selected quantity.
Orders above 70 kg (68 kg for destinations served by FedEx) can still be completed at checkout when they qualify for free shipping; otherwise, contact CorkMart for a shipping quotation. For project deliveries, provide the full delivery address and postcode, and explain any access or unloading restrictions.
Frequently asked questions
What R-value does a 50 mm board provide?
It depends on the conductivity declared for that board. With thickness expressed in metres, calculate R = 0.05 / λ using the applicable documented value.
What thickness gives my target thermal resistance?
Multiply the target resistance by the selected product's documented thermal conductivity: d = R × λ. Have the complete construction confirmed by your designer.
Can I combine two thinner boards?
Multiple layers may be considered if the installation system permits them. Confirm the layer arrangement, fixings, joints and total performance with your designer or installer.
Which thicknesses does CorkMart supply?
10, 15, 20, 25, 30, 35, 40, 50, 60, 75, 80, 100, 125 and 150 mm, as single boards or packs of 5, 10 and 25 m².
For the material overview and documentation checklist, read the Expanded Cork Insulation Board guide. Browse Expanded Cork Insulation Board, explore Cork Insulation Materials, or send your project through Request a Quote.
