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A non-combustible, breathable sheeting board with a fire rating tested up to 120 minutes. The board consists of grey cement and limestone filler, reinforced with a specially selected fibre material that can absorb and release moisture without affecting durability, strength or performance.

Cembrit Windstopper Extreme Has a very low vapour transmission resistance, enabling moisture from inside the building to pass through. This means that insulation can be placed directly against the inner side of the board. When installed according to Cembrit instructions, Windstopper Extreme will function as a temporary facade for up to 12 months. The lightweight 4.5 mm-thick version can be scored unsnapped making for quick dust free on site cutting. It is ideal for temporary weather sealing of buildings awaiting the completion of external elements.

The board is highly resistant towards both rot and fungal growth and can with stand considerable fluctuations in weather and climate conditions.

Windstopper Basic has a similar composition to Windstopper extreme and can be used in similar applications, however, can only be left exposed six months and its fire rating has been tested up to 60 minutes.

Features and benefits:

  • High density material.
  • High impact resistance.
  • Can be pressure washed.
  • Suitable backer for laminates.
  • Can be used in composite panels.
  • Non-combustible.
  • Fire tested up to 120 minutes.
  • Class A2 fire rating to EN 13501-1.
  • Can be left exposed for up 12 months.
  • Lightweight 4.5 mm-thick option.


  • Through wall solution or system.
  • Sheathing.
  • Roofline soffits.

Related literature

The following content references this product:

Standard product features


Fibre cement.


Natural grey.


14.1 kg/m².



Fire rating (to BS EN 13501-1):

Class A2-s1, d0.

Product classification (BS EN 12467:2004):

Class NT D31.


Consult manufacturer's literature for information.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-45-95/410 Cement-bonded particleboard

Product specification

An important note about specifying



Cembrit Ltd


+44 (0)203 3722300

Product reference

[Cembrit Windstopper Basic]
Can be left exposed for 6 months, 60/60 fire rating (one hour).
[Cembrit Windstopper Extreme]
Can be left exposed for 12 months, 90/90 fire rating (1.5 hours, 9 mm only).

Size (w x l)

[1200 x 2400 mm]
[1200 x 2700 mm]
[1200 x 3000 mm]


[4.5 mm]
Not available with Cembrit Windstopper Basic.
[9 mm]

Manufacturer details

Cembrit UK,
Unit 54-60,
Milford Road,
Berkshire, RG1 8LH
Tel +44 (0)203 3722300
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