Klasse G-board® Gypsum External Sheathing Board (Outwear)

We understand how challenging cement boards can be. As an alternative, Klasse offers a lighter gypsum board ensuring faster installation and a safer working environment. Designed to transform the building envelope construction, Klasse G-board's bright green appearance makes it stand out on site and its high-density design allows for easy handling, cutting and installation minimising the use of power tools and making a safer working environment for installers. 

Safe & Easy To Use

Easy to handle, 30% lighter than traditional cement boards.

Can be cut with a knife - no power tools are required for cutting and minimal dust is produced.

Can easily be curved

Can eliminate the need for a breather membrane helping to lessen project costs

Water resistant with a 12 months exposure guarantee

12-Year Warranty

Robust & Durable

High density to mitigate fire, wind and installation damage and ensure you deliver a safe, on-time project

Boasts impressive pull through strength and high impact resistance

Water resistant with a 12 months exposure guarantee

12-Year Warranty

Versatile - Can Be Used In Any Framing System

Light steel infill and oversail systems on concrete and steel frame buildings

Modular buildings

Light gauge steel frame

Timber frame buildings​


Acoustic Performance: Acoustically tested according to ISO 10140-2.

Additional insulation can be installed without detrimental effect on the fire or acoustic performance.

Product Specification

Length - 2400mm

Width - 1200mm

Thickness - 12.5mm

Average Weight - ≤ 12kg/m2

Tolerances - Length 0 to -5mm. Width 0 to -4mm. Thickness ± 0.5mm


Reaction to Fire - BS EN 13501-1 - Non Combustible Euroclass A1

Fire Resistance - BS EN 1364-1 - EI 90 and BS EN 1365-1 - REI 90

Board Type - BS EN 15283-1:2008+A1:2009, Type GM-H1

Third Party Accreditation: You can have complete peace of mind that our board has been independently determined by the BBA that it complies with the safety, quality and performance standards set.

Extensively tested in a through wall system to achieve 90mins fire protection (BS EN 1364-1) with leading brands of SFS.


Find out more

Klasse G-board Outwear Gypsum External Sheathing Board

More about G-board (Outwear)

  • Download Centre  

    Download Centre

    Datasheets, brochures and more! All available from our download centre.

  • NBS Source Partner  

    NBS Source Partner

    Klasse Group are partners with NBS, who write specification content and manufacturer information.

    NBS Specification
  • G-board Projects  

    G-board Projects

    This brand-new, state-of-the-art school features Klasse G-board external sheathing.

    View projects

It's easy to do business with us

Klasse understands your requirement for excellent service and product reliability. As a trusted supplier we provide fast quotes and rapid delivery from our UK warehouse.

We have friendly and knowledgeable experts who will help you with your external sheathing needs, every step of the way.

Contact Us