This is not exactly a DIY topic, but I'm sure hoping someone can offer advice or point me in the direction of someone who can solve the problem.
I live on slab construction and am having the ductwork cleaned today. The ductwork was built into the slab and the house is approximately 55 years old. In the process of the cleaning the contractor pointed out that my ductwork is rotting out, and at certain points the ductwork has actually rusted out exposing gravel and concrete underneath. I examined the area myself and confirmed his claim.
Any advice, suggestions, or help is greatly appreciated!
You could perhaps have the concrete tubes "sleeved", which is a process that will coat the tubes with a sealant. This would prevent dust and contaminants from entering the house, but of course you would then have to deal with the sealant, which may itself produce off-gases and such.
Outside of that, reducting to overhead would be an option, depending on the type of construction you've got. Or mini-splits.