Expert: Bruce E. Johnson - 4/29/2011

Question
QUESTION: We are planning on hiring someone to install new vinyl siding on our home, but the old siding contains asbestos. We have been told by several companies that (due the high cost of removing the asbestos) the best thing to do would be to simply install the vinyl siding over the asbestos; not only will that save money on the job, but it can also serve as an extra layer of insulation for the house.

Our only concern is that the asbestos might crack and crumble underneath the vinyl siding during installation, and fibers will get into the air ... Everyone assures us that it is perfectly safe and that this is the preferred method of dealing with asbestos siding nowadays.

In your opinion, is it better to simply install new vinyl siding over the asbestos siding and save our money?

ANSWER: Hi Alessandro, we are surrounded by asbestos in our normal every day environment.  Most places with older floor tiles, sinks,plumbing, etc contain asbestos.  Asbestos shingles are no different.  The asbestos is suspended in a matrix and unless it is sawed or crushed into a powder it is relatively inert. Covering it over with new siding shouldn't cause any airborne contaminants unless the contractor begins sawing or cutting on it for some reason. I can't say how well encapsulated your particular siding is but it is probably ok.  Most cities and counties have asbestos guidelines when it come to asbestos abatement.  Covering over the asbestos containing material is one way of handling the problem.  The health risks of minimal asbestos exposure in insignificant but if the fact that your house has asbestos siding makes you uncomfortable then you might want to check into having the siding removed.  It is an added cost but it is not out of this world costly.  A survey will cost 3-400$ and then there will be a recommendation from the surveyor which will probably state that the siding can be covered over.  I hope this information helps p,ease feel free to write again regarding this or other matters, sincerely, Bruce E Johnson. Bejohnsonconsulting.com

---------- FOLLOW-UP ----------

QUESTION: Thank you for the quick response!

I hope you don't mind if I ask a follow-up question, but might you know how the vinyl siding would be installed over the original asbestos siding? I imagine that drilling/hammering would be involved to secure the new siding, and that's where we fear that the asbestos could crack/crumble.

Does the vinyl siding act as a "shield" that keeps the asbestos relatively intact?

Thank you again for the quick response ...

Answer
Hi again Alessandro, as I mentioned in my previous answer I have no way of knowing the condition of your existing siding and the method of attachment proposed by the contractor installing the new siding.  I think, based on your concerns, you should have the old asbestos siding removed by a certified abatement contractor.  Sincerely Bruce E Johnson ..bejohnsonconsulting.com