What are the pros and cons of the different types of fixing methods for flat roofs?
- Read time: 3 minutes
- Date: 16 Aug 2022
- Flat Roofing
Waterproof membranes must be restrained to prevent them from being blown off the roof. The most common methods for securing the membrane include mechanically fixed, fully bonded, a hybrid of mechanically fixed and bonded, and ballasted. As its name suggests, the latter system uses ballast to weigh the membrane down, so will not be covered by this module because no fixing or bonding methods are required.
Each restraint system is suitable for use with a different roof build-up. The typical build-ups for each system are as follows:
Mechanically fixed systems
Structural deck
Polythene AVCL
Foil-faced insulation
Waterproof membrane
Fully bonded systems
Structural deck
Primer
Self-adhesive or torch-on bituminous membrane
Tissue faced insulation
Membrane adhesive
Waterproof membrane (generally fleece-backed)
Hybrid system
Structural deck
Polythene AVCL
Tissue faced insulation (mechanically fixed to structural deck)
Membrane adhesive
Waterproof membrane (generally fleece-backed)
What are the pros and cons of the different systems?
Because the systems are built-up and secured in different ways, they each have advantages and disadvantages which must be considered when deciding the best method for your project.
Structural concrete decks only:
