Nautilus - Roofing & Exteriors

Reinforced Bituminous Membrane (RBM)

Tried, Tested and Durable. Bituminous waterproofing membranes offer proven technology that has been installed successfully for many decades


Reinforced Bituminous Membrane – which is commonly referred to as Felt still remains one of the most widely specified and installed forms of flat roof waterproofing for both new-build and refurbishment projects.

There is a broad range of new and modified modern felts to choose from to suit different applications; all of which Nautilus are familiar with and can offer guidance and advice.

The Material

Combining bitumen with additives and a carrier such as fibreglass or polyester produces a waterproof material on a roll that is easy to install, very strong, and low in cost.

The most popular method of application is Torch On – a gas torch heats the leading face of the roll of felt which creates a molten flow of bitumen in front of the roll for it to bond to. Membranes can also be Cold Applied to suit different roofing requirements whereby they are fully bonded in cold adhesive with laps and details hot air welded. It can also be mechanically fixed and fastened through the insulation layer into the deck with laps torch sealed or with cold applied adhesives.

Key Benefits

Case study

Princess of Wales Hospital

Princess of Wales Hospital Bridgend

Bituminous Membrane

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