شینگل اصلاح شده
The physical characteristics of asphalt are actually not well suited to roofing; they are not UV stable, get brittle with age and cold, crack, alligator, and otherwise degrade relatively quickly. In order to make the asphalt more suitable for roofing, it is modified with other chemicals. MB membranes exhibit general toughness and resistance to abuse. They are typically composed of pre-fabricated polymer-modified asphalt sheets with a reinforcement layer. Polymers are added to bitumen to enhance various properties of the bitumen. The quality of MB products is highly dependent on the quality and compatibility of the bitumen and polymers, and the recipe used during the blending process. They are also highly dependent on the reinforcement within the sheet. High quality manufacturers carefully monitor the source of their raw asphalt and how it is modified. There are unfortunately many MB manufacturers and not all are as diligent.