What are the functions of a cover board?


Specification of fibreglass mat face gypsum high performance cover boards can help resolve multiple challenges of modern flat roof construction. The lightweight cover boards are installed between the insulation layer and the waterproofing membrane. Once installed, they become an integral part of a flat roof build-up that protects roof components and the building envelope during and after construction. Cover boards also serve as a homogenous, compatible substrate for the waterproofing membrane and help enhance the roof and building performance in various areas:

  • Impact and puncture resistance
  • Wind uplift protection
  • Acoustic performance
  • Fire performance

Impact and puncture resistance provided by a roof performance cover board

Cover boards provide the necessary protection for various components of roof assemblies across most types of roof systems. The strength of the cover board means that stress on the waterproofing roof membrane is reduced, and it also protects the traditionally most expensive roofing layer, the insulation.

A cover board acts as a substrate for the installation of a variety of roofing membranes. The flat surface of the cover boards helps protect the waterproofing membrane from damage caused by foot traffic, accidentally dropped tools, flying debris and similar potential hazards. 

The insulation is protected from compression caused by heavy equipment such as heating, cooling, and ventilation (HVAC) units or solar panels installed on the roof. This protection extends to the design life of the roof.

Why should we consider cover boards for enhanced wind uplift protection?

Due to their vertical pull strength, gypsum cover boards can withstand a high uplift force. As we mentioned in the last section, roof systems where the cover boards serve as a substrate for a waterproofing membrane, this helps protect the membrane during extreme storms and windy conditions. The protection a cover board offers extends to other components of roof build-up, such as the insulation and the structure itself.

In recent years, the increased frequency and force of adverse weather instances in the UK, and Europe indicate a long-term trend of storms tracking towards this area. Although the installation of cover boards has not been common practice in the UK outside Scotland, this is rapidly changing as the construction industry looks to mitigate the risk of damage to flat roofs from such events.

How do cover boards improve fire and acoustic performance of a roof build-up?

Due to a material composition that includes 21% chemically combined water, high density gypsum cover boards provide enhanced fire resistance for roof build-ups. Cover boards increase the roof’s resistance to external fire sources. When used as roof boards and installed below the insulation layer, the gypsum board can help to stop the spread of an internal fire into the roof space.

Cover boards have a proven track record in sound performance improvements. The DensDeck® Roof Board has been strenuously tested in independent acoustic laboratories to document the performance improvements it can achieve in roof assemblies. These boards are now widely used for sound attenuation in aviation and leisure buildings, data centres and biotech centres, but developments across any sector can benefit.

How can the specification of DensDeck® Roof Boards reduce capital outlay and operational building cost?

DensDeck® Roof Boards can achieve project cost savings and reduce the operational cost of a building through several avenues, including:

  • The lifecycle cost of the roof is reduced as the cover board increases the durability of the roof build up and can reduce performance issues, maintenance expenditure and costly roof repairs
  • The ease of installation and the light weight of cover boards means fewer deliveries, reduced installation time and lower cost of labour
  • As an acoustic performance solution, the board offers greater freedom of design and is often more cost effective to install than traditional acoustic solutions

Contact our experts here to find out more about DensDeck® Roof Boards and how they can benefit your project.

  1. https://www.eea.europa.eu/data-and-maps/indicators/storms-2/assessment



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