Permaboard was a building material that was made by having rubber coated asphalt sandwiched between two layers of cement. This product usually included up to 80% of asbestos in its content as it strengthened it and increased its ability to resist flames.
As long as permaboard was left intact after being installed, the risk of asbestos exposure was relatively low. Even in cases like these there was still a chance of exposure to asbestos fibers as the material could have started to deteriorate due to the passing of time. You could have been exposed if: