Duct Question: Flex replacement or Re do

[stardotstar]

Older 60"s home. Definately need to have the attic insulated and metal round duct work re-sealed and wrapped.

Hence the question: would it be better to keep the old and have it re-sealed and wrapped or removed and use more advanced newer flex?

I am assuming that when I call for estimates on this that the contractor will most likely see total replacement with flex as a cheaper more advanced replacement and certianally more profitable for him and better for us. I am I right?

[Cooked]

Flex is not necessarily cheap. If the metal duct is in good shape I'd leave it. If there are any sections that have been crushed or damaged you can replace those sections with flex. Sealing the existing ducts and insulating them well will make a world of difference.

[stardotstar]

Thanks for your thoughts, will get quotes.

[Kevin Weaver]

if a person could get up there and spray that expanding foam all over it, that would seal and insulate it. The thing is, especially the large return duct, I am sure it has quite a bit of dirt built up in it so replacing the duct will get rid of dirt too. Look to do r-6 flex or r-8. The standard stuff is r4.3

[stardotstar]

if a person could get up there and spray that expanding foam all over it, that would seal and insulate it. The thing is, especially the large return duct, I am sure it has quite a bit of dirt built up in it so replacing the duct will get rid of dirt too. Look to do r-6 flex or r-8. The standard stuff is r4.3

There is plenty of room to work, did not know that spray was available option?

Hmmmmm.

[energy_rater_La]

it isn't.
foam isn't for sealing ductwork.
I've seen some real messes when
homeowner allowed foam insulator to
foam ducts.
unlike mastic it doesn't fill all the cracks,
and can actually encapsulate gaps and voids
next to ductwork.

use approved methods of sealing ductwork.
there is a reason that products are tested
and rated for different purposes.

you can't even use foam board in a return,
so you don't want it in contact with the
ducts.

I'd unwrap, mastic seal and re-wrap with
R-8 ductwrap, if the hard pipe is in good
shape and sized properly.

you should also check at supply box to seal these areas too.
returns should also be sealed. equipment to plenums should
be mastic sealed.

mastic= approved method of sealing.


best of luck.

[stardotstar]

Thanks for the clarification.