Berryka, I assume this is a new home to you but was built more than 30 years ago. Your inspector identified lagging that is potentially asbestos containing material. It may or may not in fact contain asbestos, and a simple PLM test at a local analytical lab can verify this. If the material is in good condition, you don't NEED to do anything. You may economically and safey encapsulate the existing tape in non-asbestos lagging and mastic. Any heating supply store can sell you mastic and cloth tape that will seal the existing tape, and will prevent leaking in the pipe joints. Do not use duct tape. The advantage of mastic for this job is that it is water permeable. This will make future removal of the mastic and underlying asbestos (?) safety possible using wet removal methods.