Help identifying duct material?

[Welmoed]

I did a "walk and talk" this afternoon for a client who was considering bidding on a house and wanted to know if there were any major big issues before putting in his offer. One issue I found is in-slab ductwork. I was able to get a few pictures but couldn't say what the ducting material appeared to be. I was hoping someone might be able to give me an idea of what the ducts are made of. Yes, I know a definitive identification would involve taking a sample and sending it to a lab or something. He's just concerned about the possibility of asbestos (house was built in 1956).

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[Bill Kibbel]

From what I can see in the photos, it looks like sheet metal that transitions to what is likely Transite (cement-asbestos). Common for in-slab ducts for that era.

https://inspectorsjournal.com/forum/top ... C_ID=15495

[Scottpat]

I agree with Bill... Looks like Transite air duct. One plus is that I do not see standing water which is what I usually find with in slab air ducts!

[inspector57]

I agree, looks like asbestos on at least parts of the system. On the plus side, in slab ducts were a dumb idea the day they were installed and need to be replaced. Seal it off on both ends and the asbestos won't hurt anyone until they bulldoze the house.

[Jim Katen]

In the third picture, I see a spiral seam. That's not typical of transite - at least not the transite in my area.

[John Dirks Jr]

In the third picture, I see a spiral seam. That's not typical of transite - at least not the transite in my area.

Good catch. But I don't know, there could be various types.

Here's an interior of transite. See the linear composition?

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Here's an exterior shot showing the dimpled nature of the surface.

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[Mark P]

So when you suspect the ductwork in the slab in transite what do you recommend.

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