Should Mastic Be Applied inside Ducts?
We hired a contractor to clean our crawl and seal our ductwork. The company used Hardcast 321 mastic. We are concerned becasue they smeared into the floor vents from above and all around the cold air return. I have attached a couple of pictures. Should mastic be applied inside the ducts like this, is it harmful/toxic?
Thank you for any info/advice.
Posted Oct 29, 2012 12:34 AM ET
Edited Oct 29, 2012 12:39 AM ET
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