.jpg)
1 Review
View Product Reviews20mm Celotex TB4020 PIR Insulation Board 2400mm x 1200mm
| 12+ boards | 24+ boards | 40+ boards |
| £12.49ex. VAT | £12.36ex. VAT | £12.10ex. VAT |
Coverage required
Nationwide Delivery
Tue 23 Sep
- 0days
- 15hrs
- 39mins
- 39secs
Learn more
Pay in 3 interest-free payments
Split your purchase of £12.74 into 3 with no sign-up fees or late fees.
£4.25
today
£4.25
1 month
£4.25
2 months
How it works
- Choose PayPal at checkout to pay later with Pay in 3.
- Complete your purchase with the first payment today.
- Remaining payments are taken automatically.
Pay in 3 is a form of credit, so carefully consider whether the purchase is affordable and how you will make the repayments. Be aware of the possible impact of using Pay in 3 and of missing payments, including making other borrowing more difficult or more expensive. Pay in 3 eligibility is subject to status and approval. 18+ UK residents only. Available for purchases of £30 to £2,000. Terms and conditions apply. PayPal Pay in 3 is a trading name of PayPal (Europe) S.à r.l. et Cie, S.C.A. 22-24 Boulevard Royal L-2449, Luxembourg.
Learn more
Buy now. Pay with Klarna at your own pace.
Get what you need for your next project, choose how you pay.
Pay in 30 days
£12.74
Pay in full
Klarna's Pay in 30 days is an unregulated credit agreement. Borrowing more than you can afford or paying late may negatively impact your financial status and ability to obtain credit. 18+, UK residents only. Subject to status. T&Cs and late fees apply.
Pay over time
£4.25
Every 30 days
Pay in 3
£4.25
today
£4.25
in 30 days
£4.25
in 60 days
Klarna's Pay in 3 is an unregulated credit agreement. Borrowing more than you can afford or paying late may negatively impact your financial status and ability to obtain credit. 18+, UK residents only. Subject to status. T&Cs and late fees apply.
How it works
- At checkout select Klarna.
- Choose your payment plan.
- Different payment plans may be shown depending on the purchase amount and credit score.
- Complete your checkout.
- The amount will be charged based on the payment plan you chose.
Learn more
Pay in 4 interest-free payments
Split your purchase of £12.74 into 4 with no sign-up fees or late fees. Your purchase will be split into 4 payments, payable every 2 weeks
£3.19
today
£3.19
second payment
£3.19
third payment
£3.19
fourth payment
How it works
- Choose Clearpay at checkout to pay later with Pay in 4.
- Complete your purchase with the first payment today.
- Remaining payments are taken automatically.
Clearpay is unregulated credit. Use responsibly. 18+, T&Cs and late fees apply at clearpay.co.uk/en-GB
Clearpay lends you a fixed amount of credit so you can pay for your purchase over 4 instalments, due every 2 weeks. Ensure you can make repayments on time. You must be 18+ and a permanent UK resident (excl Channel Islands). Clearpay charges a £6 late fee for each late instalment and a further £6 if it’s still unpaid 7 days later. Late fees are capped at £6 for orders under £24 and the lower of £24 or 25% of the order value for orders over £24. Missed payments may affect your ability to use Clearpay in the future and your details may be passed onto a debt collection agency working on Clearpay’s behalf. Clearpay is credit that is not regulated by the Financial Conduct Authority. T&Cs and other eligibility criteria apply at clearpay.co.uk/terms
Product Overview
Delivery & Returns Information
How Our Delivery Works
We work with a nationwide network of trusted suppliers. As a result, items in your basket may be supplied by different suppliers and delivered separately. Where this applies, you'll see multiple delivery charges at checkout. We always aim to group products from the same supplier to keep delivery costs as low as possible.
Delivery Areas & Charges
Delivery charges listed on our website apply to mainland UK, excluding the following postcode areas: AB, CF, DD, DG, FK, KW, IV, LA, LD, LL, NP, PA, PH, SA, SY
If your delivery address falls within one of these postcode areas, we’ll be in touch before processing your order to confirm any additional delivery costs.
Please note: We do not currently offer delivery outside the UK mainland.
Standard (Nationwide) Delivery
| Insulation, Plasterboard and Drylining Products | |
|---|---|
| ORDER VALUE | DELIVERY CHARGE |
| Under £350 | £35 ex. VAT |
| Over £350 ex. VAT | FREE |
| Timber & Sheet, Building Materials, Joinery and Gardens & Landscaping Products | |
| ORDER VALUE | DELIVERY CHARGE |
| Under £100 | £15 ex. VAT |
| Between £100 - £300 ex. VAT | £10 ex. VAT |
| Over £300 ex. VAT | FREE |
| Screws & Fixings and Adhesives & Sealants | |
| ORDER VALUE | DELIVERY CHARGE |
| Under £50 | £5 ex. VAT |
| Over £50 ex. VAT | FREE |
Express Delivery
| Express Delivery - Insulation and Plasterboard & Drylining | |
|---|---|
| ORDER VALUE | DELIVERY CHARGE |
| Under £400 | £50 ex. VAT |
| Over £400 ex. VAT | £35 ex. VAT |
| Express Delivery - Timber & Sheet, Building Materials, Joinery and Gardens & Landscaping Products | |
| ORDER VALUE | DELIVERY CHARGE |
| Under £300 | £50 ex. VAT |
| Over £300 ex. VAT | £35 ex. VAT |
Returns
We offer a 30 day returns policy on any faulty products.
Key Features
- {{home}} Use in floors, framed walls and pitched roofs
- {{grade}} Aluminium composite facing on both sides
- {{thermostat}} 0.022 W/mK thermal conductivity
- {{build}} Easy to handle and install
- {{public}} Zero Ozone Depletion Potential (ODP)
- {{verified_user}} BBA certified
Technical Specification
| Material Type: | PIR |
|---|---|
| Thickness: | 20mm |
| Width: | 1200mm |
| Length: | 2400mm |
| Sales Unit: | Board |
| Sales Unit Coverage: | 2.88m2 |
| Brand: | Celotex |
| Manufacturer's Reference: | TB4020 |
| Weight: | 2.28kg |
| Thermal Conductivity: | 0.022W/mK |
Technical Downloads
Product Overview
Foil-faced PIR insulation board for use in floors, walls, and roofs.
Part of the TB4000 range, it is used to limit thermal bridging at reveals, junctions, and edges where insulation layers are interrupted.
At 20mm thick, this is the slimmest option in the range, suited to over-boarding, detail work, and space-constrained applications.
Features & Benefits
- Thermal conductivity (0.022 W/m·K): Reduces the thickness required to meet U-value targets.
- Low-emissivity foil facings: Reflect radiant heat across unventilated air gaps, cutting thermal transfer at junctions.
- TB4000 range (thermal bridging control): Improves continuity of insulation where up to 30% of fabric heat loss can otherwise occur.
- Rigid PIR core: Lightweight yet robust, easy to cut and install with standard tools.
- Moisture resistance: Closed-cell core prevents water uptake and preserves thermal performance.
- Environmental credentials: Zero ODP, low GWP blowing agent, and BRE Green Guide Rating A.
- BBA certified (17/5405, 16/5352): Independent assurance of performance across roofs, walls, and floors.
- Board size 2400 x 1200mm: Large-format sheets reduce installation time.
- Thickness 20mm: Slimmest PIR option, enabling insulation where space is most limited.
Applications
- Thermal bridging details (reveals, lintels, junctions): Limits cold spots, condensation risk, and heat loss where insulation layers are interrupted.
- Roofs (pitched/flat): Useful for upgrades at rafter lines, perimeter upstands, or overlaying to reduce bridging.
- Walls (timber frame/masonry): Applied at reveals, edges, or internally to improve continuity.
- Floors (beam & block, slab, timber): Commonly used as perimeter upstand insulation or for targeted slab upgrades.
Installation Guidance
- Cut and fit tightly: Use a knife or fine-tooth saw; maintain close joints to avoid thermal bypass.
- Seal or tape as specified: Ensures continuity with air and vapour control layers.
- Protect on site: Store boards flat, dry, and covered until required.
Compliance & Performance
- Thermal conductivity: 0.022 W/m·K (BS EN 12667).
- Compressive strength: ≥140 kPa (BS EN 826).
- Reaction to fire: Euroclass E (BS EN 13501-1).
- Environmental performance: Zero ODP, low GWP, BRE Green Guide Rating A.
Related Articles
How to Insulate Under Floorboards Without Removing
How To Install Celotex Insulation Boards
