under slab transite return ducts

[stevebarry]

Remodling and found under slab ducts are transite and had flooded at one point in time as there is mud in them - assuming when the slab was poured back in the 60's

Whats the danger factor in keeping these - are they very friable as they are known to contain asbestos? should I be concerned about having a duct cleaning company clean them out and using them or should I abandon the system and run return through the attic?

[Chad Fabry]

should I abandon the system and run return through the attic?

Yes

[hausdok]

Don't know much about them; however, is it possible to have them commercially cleaned and then the interior sealed with epoxy similar to what's done to rehabilitate pipe?

OT - OF!!!

M.

[inspector57]

IMO it was always a dumb idea to place ducts below grade and now add the transite to the equation and it just got stupid. Seal the ducts after filling to prevent moisture, mold, critters, etc. and find another way to route the air ducts.

[kurt]

An air return in a slab isn't going to do much for efficiency or function. I'd move it simply because its a return in the slab. Get it up on the ceiling, or better yet, get some hi-low vents on the wall with adjustable convectors to balance air flow.

I used to freak out when I found transite ducts, so I went on a tear for sampling to determine if there was any fiber release. Never found any. I did quite a bit of research a long time ago looking for any info indicating there was fiber release. Never found any indicating the stuff was in fact, hazardous. Maybe there's something new; I don't know.

[Chad Fabry]

I used to freak out when I found transite ducts, so I went on a tear for sampling to determine if there was any fiber release. Never found any. I did quite a bit of research a long time ago looking for any info indicating there was fiber release. Never found any indicating the stuff was in fact, hazardous. Maybe there's something new; I don't know.

That's because most of the time the ducts are damp and stay damp. Legionnaires disease is more threatening than airborne asbestos. However, I was in a house a few weeks ago where the was white powder on the walls and floor around the supply registers.

[kurt]

I see plenty of them where they're bone dry and have never apparently been wet.

White powder outside a duct like this would make me think someone was blowing white powder poison into the ducts to kill stuff.

Does transite degrade to white powder?

This is all academic. I'm in the same box as everyone else regarding what they put in their reports. Does anyone have anything about asbestos fiber release from transite?