Is this Transite?

[Pierre Coulombe]

Can anyone tell me if this is Transite that I found at today's inspection? It was rigid metal ducting with this insulator around it. Yes, I know that the duct tape in the photos is not allowed, but it was better than the painter's tape I found holding ducting together at another inspection.

[Gunnar Alquist]

Pierre,

To the best of my knowledge, Transite is a cement-asbestos material used for pipe, siding, etc. It might be that Transite was used for ducting as well, but I have never seen it. If I remember correctly, it was manufactured by Johns-Manville.

What you have there is probably asbestos duct insulation. Very common in the 1950s and 1960s. It is very friable and a health issue.

[John Dirks Jr]

What's pictured is not Transite. As Gunnar said, its does look like the wrap on the duct could contain asbestos.

Gunnar, I see Transite ductwork under slabs in my area several times a year. One particular past builder in the area filled entire neighborhoods with the stuff. It's also randomly found here and there. Almost always when they wanted to run ductwork under a slab.

[Pierre Coulombe]

Thank you, Gunnar and John. Appreciate the corrections and information.

[Gunnar Alquist]

So Pierre,

Why not post this question on the TIE?

I mean, I am the TIE Grandmaster! :cool:

(of course, the TIE doesn't have these cool emojis)

[Gunnar Alquist]

Gunnar, I see Transite ductwork under slabs in my area several times a year. One particular past builder in the area filled entire neighborhoods with the stuff. It's also randomly found here and there. Almost always when they wanted to run ductwork under a slab.

JD Jr,

That's very interesting. Around here, builders used standard sheet metal when running ducting in slabs, but did not fully encase the ducts in concrete. As you might have guessed, the ducts have corroded-out and now circulate soil throughout the house when the furnace or AC is running (probably mold spores and other nasty contaminants as well).

I wonder which is worse... Transite is reportedly non-friable as long as it is not broken (Not that I would count on that). Of course, there is no way to tell the condition of a duct that is buried without running a camera into it (which might damage it and knock loose some asbestos fibers). Can these old Transite ducts be sleeved with some other type of duct? I suppose it would be better to just abandon the system and put the ducting in the attic, but that is not always going to be possible.

What do people do in that case?

[John Dirks Jr]

Gunnar, when a structure is a single story with an attic space, I've seen the Transite ducts abandoned and a new HVAC system installed via attic space. In the two story structures its more complicated to do that and get the distribution adequately down to the first floor.

I have seen sealer used to line the Transite and there is a company in the area that does it. It's not a cheap process though.

https://www.ductarmor.com/the-product/

[davidlcarbone]

It seems to me that it is not transite. I am not an expert but after reading some replies I can say that it is not a transite.