Mobile U-value Calculator

The free Celotex App provides instant mobile access to our professional U-value calculator.

U-value Calculator
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IMPORTANT: On 1 September 2017, Celotex took the precautionary measure to temporarily suspend the supply of Celotex FR5000, Celotex CG5000, Celotex CF5000 and Celotex SL5000 while we investigate the results of recent tests (Parts 6 and 7 of British Standard 476). In addition, we have recently identified a compliance issue relating to our calculation and testing of the declared lambda value of products in the 4000 and 5000 ranges and the Crown-Bond and Crown-Fix products within the Crown Flat Roofing range. Due to this issue, the suspension of the 5000 range will continue and now includes the FI5000 and GD5000 products. Materials relating to the 5000 range products are for information only.  Please note that all products in the TB4000, GA4000 below 100mm, PL4000 and CW4000 ranges manufactured after 15 December 2017 will be marketed from January as Celotex 3000 with a declared lambda value of 0.023 W/mK.

Please use the link below to read our full statements regarding declared lambda:

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Please use the link below to read our latest statement regarding Class 0:

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The Celotex U-Value mobile app has been designed in response to the increased use of our online U-value calculations browser application on mobile devices. This professional calculator provides much-improved service and mobility, allowing you to specify your desired U-value before immediately calculating the required insulation thickness and product solution.

The introduction of the App is a time saver for specifiers wanting to create buildable solutions and with even more wall, floor and roof applications included; it will offer you instant solutions which meet your U-value requirements.

The U-value App is available on Apple devices including the iPhone, iPad and iPod touch as well as any Android devices.

Option A


  1. Visit the app store
  2. Download the app to your iTunes
  3. Then sync your device to iTunes
  4. Start using the U-value calculator app

Option B


  1. Visit Google play
  2. Click install
  3. Sign in if required and select your device
  4. Start using the U-value calculator app

It really is as simple as that!