Traditional roofing felt was popular due to it's lightweight properties as well as ease of installation and budget-friendly prices.  It was also good for more complex roofs due to it being easily cut to size and joined around different fluctuations in a roof.  However with a life span ranging between 5-10 years it wasn't sufficient for industrial and commercial use.  

Since the 1930's 5 different types of single ply roofing membranes have been introduced to the market offering a minimum of 25 years lifespan with some still in existence at 50!

For clarity these are PIB, TPO, TPE, EPDM and PVC.

In order to chose the appropriate flat roofing membrane I will assess the following on each job:
 

• Size of roof

• Roof design

• Locality of roof and/or other buildings

• Budget

• Architect requirements (if appropriate)

• Insurance inclusions & exclusions (if appropriate)

• Availability of membrane