Ductwork

[25skeet]

I know this is late but here in great falls mt they have adopteed the international code witch calls out all duct must be sealed.

[nathan9999]

Does it make a difference if the ducts are flex versus sheet metal?

All of the new construction I have seen locally seem to use round flex ductwork. In this area everything is a split system (gas heat) with the ductwork in an unconditioned attic.

Is there a sealant used for this flex ductwork?

[dash]

Originally posted by nathan9999
Does it make a difference if the ducts are flex versus sheet metal?

All of the new construction I have seen locally seem to use round flex ductwork. In this area everything is a split system (gas heat) with the ductwork in an unconditioned attic.

Is there a sealant used for this flex ductwork?

Yes,mastic is what is the best.

[bornriding]

About what you said - duct leakage
Can you be more specific, referring only to fabricated duct with s-locks & drives
Rate or percentage of leakage ??