Low Slope/Flat Roof Debate

Tpo Vs Modified Bitumen

In the roofing industry there is an ongoing war on the durability and hardiness of low slope membranes, specifically TPO and Modified Bitumen. Tpo is Generally installed in Comercial and new construction and can vary in application methods and dates back to the 90’s and is generally adhered and combined with high temp welds from heat gun or robot. Its benefits include its hardiness to modern pollution and oils and its reflexivity. Tpo varies is Mill thickness and life expectancy. Most commonly Tpo varies in 45-90 mill and is applied directly to insulation.

Modified bitumen or Roll roofing has been around since the 70’s and is a method of application by way of open flame welding. Mod Bit comes in Cold application, self adhered, Hot Torch and Hot mop. Material can be APP or SBS. Modified roofing is known for its sandwich application of layers. Modified Bae is 80 mills and APP cap is 180 mills. Modified bitumen generally requires a base, smooth base and its final cap sheet known as 3-ply application.

Low slope roofing is considered a technical roofing trade and can vary in compatibility and is known for its cornucopia of methods and simplicity to adapt to an existing roof.

Tinroof recommends a proper re roof for residential roofs, meaning starting from scratch and building from bare deck. Cost for residential TPO or Modified are in the same neighborhood. Comercial and investment properties generally a retro fit is recommend, or restoration repair compatible and adaptable to exiting roof to alive demo cost, or replacement cost with few modifications and the trouble of a new roof and cost.

A proper inspection, and replacement options is recommended along with a repair option and roof life expectancy.