Can you tell me what might be done with a very old home with exterior shingles of asbestos? Is there a proper way to safely seal & paint over? Can they be dismantled? What is the best way to address this homeowner issue?
Asbestos was a very common siding material used in the 50's. This type of siding is actually known as "Cement Asbestos" as the asbestos is contained inside of a cement binder.
The risk of asbestos exposure is based on how friable it is (how easily it gets deteriorated). If the asbestos can be easily released to the air, then there is a substantial risk of exposure. This would be the case, for example, with heating pipe insulation made of asbestos.
However, cement asbestos siding presents very little risk and is actually quite durable. You need only to paint it about every 7 years to keep up appearances. Since it is not organic, it will not rot - ever!
The only time asbestos siding needs to be removed is when new siding is installed (never go over asbestos). In this case, tiles can be removed by punching the nails through with a nail set, which will allow them to be removed whole with very little risk of exposure. Once removed though, disposal can be a problem as some municipalities have regulations pertaining to the disposal of any hazardous material. Be sure to check local regulations and practices before taking them down.