Understanding Flat Roofing Terminology

As a homeowner, if you decide a flat roof is the best solution for any area of your home, you might be confused by which type of flat roof you need or what’s what in terms of the lingo. Don’t be put off by the various industry jargon surrounding flat roofing as they are relatively straightforward. Here are some of the different terms you might come across:

Reinforced Bitumen Membranes

This sounds complex but in fact just refers to 2 or 3 layers of waterproof and flexible materials, like felt which are rolled out and fixed together with hot bitumen to form a waterproof covering. This type of flat roof will likely need a further membrane on top to protect it, such as shingle or gravel. This provides some weight, protecting the roof from wind, sun exposure and from anyone walking across it.

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Structural Deck

These are the materials that form the roof. Ideally, these must be as strong as possible to avoid any chance of sagging. The toughest material is concrete but this isn’t found in residential properties very often. Most homeowners choose something like plywood, strand board or timber board, for example. The structural deck sits atop the ceiling joists, which are the strong planks holding it all together. For help from a Cheltenham Roofer, visit a site like http://stormroofingltd.co.uk/


Some types of flat roof are specifically designed to walk on, such as a roof terrace or balcony. As such, a stronger material will be needed. There are many different varieties of tile, including rubber, bitumen, concrete, plastic and fibre cement. The roof must be strong enough to take these heavier materials, as well as the weight of people.


This is one of the original materials for constructing a flat roof. Felt is bonded to asphalt, rolled out and then positioned with nails or cement. Several layers are required, with the top one consisting of a weight like gravel. Many people choose this option as it’s probably the cheapest, however, it is also the one type that will need replacing most regularly.

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Ethylene Propylene Diene Monomer

A bit of a mouthful – this is a new rubber material that has more recently come to the market. Felt has always been the traditional material of choice but EDPM is stronger and longer lasting. It also comes in a roll but offers a much smoother and more aesthetically pleasing finish.

Single Ply

These membranes are very strong, flexible polymer materials made from substances like PVC, for example. It is only a couple of millimetres in thickness and is available in 20m rolls. The membrane is secured using special mechanical fasteners consisting of lengths of plastic tubing including screws that pierce the membrane and attach to the structural deck below.