Thread: Duct Material in 1960's Home

I came across a duct material in a mid 1960's home which I have never seen before. The exterior of the ductwork appears to be some form of corrugated cardboard. And the joints were taped and covered in a transparent form of sealant which appeared to be pretty effective at sealing. Wondering what this is made off (interior), what it is called, and if there are any known problems with it. Thanks!

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1960--could be asbestos like material--recommend having tested by lab--before doing anything--like removing

cvf

Originally Posted by CHARLIE VAN FLEET

1960--could be asbestos like material--recommend having tested by lab--before doing anything--like removing

cvf

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That's a Big 10 Four !
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I agree that the tape used to seal should be called out for further testing. But did you also mean the duct work itself might contain asbestos? The ductwork appears to be a corrugated cardboard. At least on the exterior.

Originally Posted by Leo Leidlein

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I agree that the tape used to seal should be called out for further testing. But did you also mean the duct work itself might contain asbestos?
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The ductwork appears to be a corrugated cardboard. At least on the exterior.

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Inside or Outside The Duct Sealant Material is being used to Seal Gaps from the outside to the inside.

Thus a gap between the outside now exposes the inside to the material used to Seal the opening between the outside to the inside.
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Billy, thanks. I'm with you on the tape. Understand that at joints it is probably also going to be exposed at the interior of the ductwork. But I am also interested in the the duct itself. Curious if you have seen this lined with anything?

Originally Posted by Leo Leidlein

Billy, thanks. I'm with you on the tape. Understand that at joints it is probably also going to be exposed at the interior of the ductwork. But I am also interested in the the duct itself. Curious if you have seen this lined with anything?

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Sorry No.
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corrugated asbestos insulation, which most are familiar as having been used around pipes was often used on ducts as well as applied on and in wall cavities, ceilings, etc. not just wrapped around steam and hot water pipes.

what material the inside is can only be guessed upon. shape and offsets suggest metal work underneath, although also entirely possible to be fiberboard or other material which may or may not contain fibers of concern.

however, agree completely that as pictured including the fabric mesh and mastics appears to be suspected asbestos containing materials, including the possible suspected asbestos paper or corrugated asbestos layer on the pictured duct or plenum.


most references regarding corrugated paper (asbestos containing) won the web will be relating to its use as pipe wrap. It was used for a wide variety of purposes in both residential and commercial buildings. Its most common use was in the thermal insulation of pipe coverings, hot water lines and fireproofing around stoves and fireplaces, or used in walls as an added layer of insulation. i have found it used extensively in "better" homes completely wrapping and encasing all metal duct work otherwise exposed in basements and in enclosed interior and exterior wall cavities for homes with forced air furnaces and those fitted with split air conditioning systems, especially those installed post wwii which were originally oil-fired and may still be or later converted to gas fired or coal fired generally converted to gas fired. mastic joints with asbestos cloth fiber and sometimes completely further wrapped and encased and painted.

strongly recommend specialist.

sorry for the lack of capitalization, i need to fix the key on the keyboard.

sampling for testing and/or remediation is not diy.

Many thanks H.G. !

Originally Posted by Leo Leidlein

Many thanks H.G. !

the material most used if not sheet metal was the forerunner of the fiberglass board we have today, it's primarily made up of Compressed rockwool and animal glue, the tape also used an animal based glue the was heated with an Iron to facilitate adhesion

The joints are covered with asbestos wrap. They have been encapsulated with polyurethane in recent times to keep it from getting damaged and becoming airborne.