EducationCoventry University
Coventry, West MidlandsReinforced Bituminous Membrane
04Waterproofing system
Reinforced Bituminous Membranes
Reinforced bituminous membranes are multi-layer systems built up from polyester-reinforced sheets. Two or three layers give genuine redundancy, so a puncture in the cap sheet does not mean water in the building. It remains the most robust option where a roof takes foot traffic and abuse.
- Layers
- Two or three layer systems
- Application
- Torch-on, self-adhesive or cold applied
- Typical guarantee
- 15 to 20 years
- Strength
- High puncture and tear resistance
About Reinforced Bituminous Membranes
Modern reinforced bituminous membranes have very little in common with the felt roofs that gave the material its reputation. Polyester reinforcement and modified bitumen produce a system with high tensile strength, excellent puncture resistance and a service life comparable with any other flat roof system.
The multi-layer principle is the point. A single ply or liquid roof is one line of defence. A two or three-layer bituminous system is two or three, fully bonded together. On roofs with regular maintenance access, roof gardens above, or plant that gets serviced frequently, that redundancy earns its cost.
We install torch applied, self-adhesive and cold-applied variants. On occupied buildings we specify torch-free systems as standard, which removes hot works and the fire risk that goes with them without giving up the multi-layer build-up.
Best suited to
- Roofs taking regular foot traffic
- Storm damage reinstatement and re-decks
- Buildings where redundancy is a priority
- Roofs beneath green or ballasted finishes
Sectors we install it in
Typical build-up
Section / outside in- 01
Cap sheet
Mineral or foil finished, UV stable
- 02
Underlay sheet
Fully bonded to the layer below
- 03
Thermal insulation
Bonded, with a bitumen-compatible facing
- 04
Vapour control layer
Usually a bituminous sheet, fully sealed
- 05
Structural deck
Concrete, metal or timber
Specifying this system?
We issue technical submittals, U-value calculations, wind uplift calculations and detail drawings as part of the tender return.
Send us the specificationDelivered
All case studiesProjects using this system
Common questions
Bituminous, answered
Do you still use torch-on systems?
Only where the building and the risk assessment allow it. On occupied buildings, schools and healthcare sites we specify self-adhesive or cold-applied systems as standard so there are no hot works on site at all.
How does it compare with single ply on cost?
Installed cost is broadly comparable. Bituminous tends to win where the roof takes traffic or needs redundancy, single ply where the area is large and open. We will tell you which is right for your building rather than which we would rather install.
Other systems and services
Tender & project enquiries
Have a project for us?
Send Absolute Waterproofing your roofing enquiry or tender. Drawings, specifications and a link to the tender information can all go with it, and our estimating team will come back to you with a considered price rather than a holding email.
