Most homes built before 1978 will contain asbestos materials in varying percentage levels both inside and outside the structure. While many people recognize "popcorn" ceilings may contain asbestos you should also know outdoors asbestos was used in roofing and siding. Indoors, it was also used in floor/ceiling tiles, putties, caulks, paints, cements, plasters, and pipe insulations.
Confirmation and percentage level of asbestos can only be assured via sample testing, which is not part of a standard property inspection. I do not know when your inspection contingency will expire; however, you should confirm whether the roof tile do in fact contain asbestos and at what concentration. You will be happy to know http://www.kellco.com is a local asbestos testing lab where you can get "same-day" results. Clients of mine drove a sample to the lab and received the results in less than 3 hours; charge was $35. Test results showed a 2% asbestos concentration (The Federal Clean Air Act of 1970 gave the EPA authority to regulate material containing more than 1% asbestos fibers.)
While there's no law preventing an owner from removing asbestos themselves that I am aware of (the homeowner must still follow the Rules & Regulations of the Dept. of Environmental Quality for disposal) there is legal exposure of not disposing of asbestos properly. The more important consideration is your own potential asbestos exposure "doing it yourself", which I would not do.
Be aware professional removal is costly and often seen as the solution of last resort. Here's a link for finding certified professionals to remove the roof so you can obtain a quote, if needed:
For more info see:
If you like the property, the location and the price, you should look into professional asbestos removal/remediation. There are several companies in the Bay area who can do this for you. Your agent, if you have one, may even have some recommendations.
How may I help?