Single ply roof build up

Single ply roof build ups are warm, inverted or cold roof systems that use flexible but strong membranes to form the final waterproofing layer. There are two types of single ply membranes, thermoplastic and elastomeric. They both come in a variety of thicknesses to suit the application for both residential and commercial sectors.

Both types of single ply membranes are composed of synthetic polymers or natural rubber to form a homogenous roof surface. Some applications benefit from membranes reinforced with glass fibre or polyester.

The substrate that a single ply membrane attaches to will depend on the type of roof system. In conventional cold roofs, this will be the roof deck, in warm roof systems it is the insulation layer. Increasingly cover boards are used in roof build ups where higher performance is required, especially if the building is being insured by FM Global Cover boards are placed over the insulation layer for extra protection and to improve the performance of a roof system. A vapour control layer is placed between the insulation and the roof deck to protect the insulation from moisture. Some roof build ups can also utilise roof boards between the insulation layer and the roof deck to help protect the roof if there’s a fire inside the building.

Once the single ply membrane is attached, the joints are sealed to form continuous waterproofing that results in a durable roof system.

What are the benefits of single ply roof build up

• Durable
• Lightweight and flexible
• Easy to install and repair

What are the benefits of DensDeck® Roof Boards for a single ply roof build up?

Single ply membranes can be manually fixed, welded, or fully adhered to a substrate. The most common method of mechanical fixing uses screws complemented with washers and pressure plates to protect the single ply membrane from puncturing. DensDeck® Roof Board cover boards provide the ideal substrate for all types of single ply installations with the added protection of the membrane from puncturing. For adhered and self adhered membranes, they remove compatibility issues and create a strong bond with the waterproofing membrane.

DensDeck® Roof Board cover boards also help to protect the single ply membrane against puncture by dropped tools or other debris that can get pushed into it. Although the installation is relatively fast, accessories on roofs such as skylights, air vents, plumbing vents or others will require the membrane to be cut in situ to fit. The cover board provides enhanced moisture protection during the installation and through the design life of the roof system.

Cover and roof boards improve the fire performance of the roof system and limit noise travelling through the roof.

Key benefits of DensDeck® Roof Boards for single ply roof build ups

  • Bond strength
  • Fire performance
  • Acoustic performance
  • Extended roof life
  • Puncture resistance (wind and hail)

technical data & downloads

DensDeck® Prime Roof Board
Thickness (mm)6.4 (¼ inch)12.7 (½ inch)15.9 (⅝ inch)
Length (mm)243824382438
Width (mm)1219


Datacentre construction has a unique set of demands on the building envelope performance. The roof system must be robust and waterproof. Any moisture penetrating through the building envelope could cause service disruption with considerable commercial impact or even damage the expensive equipment. Specification of fibreglass mat face gypsum cover boards is ideal for both new datacentre projects and roof renovations that seek fast project delivery times and exceptional building performance.

Heritage buildings

Conservation and refurbishment of roofs for heritage buildings demands attention to detail. They often use roof coverings made from traditional materials, making installation more time and labour intensive.

Heritage roofs may have areas that are difficult to access, posing a challenge when it comes to the installation and the performance of the roof system. Cover boards are specified to make roof refurbishment easier. They also help increase the building performance of traditional, heritage buildings.

Museums & libraries

Roofing systems for museums and libraries have the important function of protecting valuable collections and creating a safe, comfortable space for the public visiting the facilities. Museums and libraries often combine traditional heritage buildings and striking modern extensions.

This allows architects and designers to blend high performing heritage roof refurbishments with modern green, metal, solar panel roofs, roof terraces with parapet systems or a fusion of the various roof types. Cover boards are a crucial part of these roof build ups capable of enhancing their performance and extending their design life.


Airports, hangar and maintenance buildings, car parks and other buildings in the aviation sector present their own set of challenges. These projects have intensive schedules and once finished, the highest level of building performance is expected to keep passengers comfortable and safe.

The performance enhancing capabilities of fibreglass mat face gypsum cover boards are ideal for specification in the aviation sector.


The construction of biotech centres must overcome a very specific set of challenges. These buildings fall within the critical sector and the expectation is that their roofing systems must be very robust.

Specification of fibreglass mat facer gypsum core cover boards enhances the performance and longevity of roof systems for biotech centres. It can also target improvement in specific areas of building performance, as required by each project.

Send a project or specification enquiry

Start your project or simply get specification advice by dropping us a message.
One of our team will be in touch as soon as possible.