Replacing under belly duct work

[Mark440]

I'm noticing a huge difference in the amount of airflow from one side of the house verses the other. My ducts "T" at the furnace and then shoot straight down each side.

My last visit to the crawlspace revealed a wad of duct tape at the "T" the size of Texas from the previous owner. I think I want to just chuck it all out in the yard and start over.

Also, the big tubes that connect from the "T" to the registers is laying on the ground. Not seeing any suspension pieces anywhere.

Are there any major drawbacks to replacing all of this mess with aluminum and it the duct work just be hung from the underbelly frame?

I'm not a seasoned pro with this type of repair, but have very good mechanical aptitude. Can I do it myself - or should I contract it out?

[Robert]

Hi,


I believe you are referring to the cross-over duct that connects

the two sides. In a double-wide you have two main trunklines, one

for each half of home, then the cross-over connects them.



Best method is all metal, two 90* elbows and hard metal between

them.


All wrapped in insulation with an outer vapor/moisture barrier.


Next best, two 90* ells and flex duct stretched tight between

them.


No sagging or kinking this way.


IF you wish to replace the trunklines also and have them below underbelly, you will have to make sure belly is sealed tight and waterlines insulated to keep from freezing IF that is a possibility.


Also, below the belly leaves the chance of rodents damging the ductwork.


This can become intensive, depending on how far you wish to go, but is doable for DIY if you're willing.


Would be very costly to have it done.



Thanks for inquiring,
Robert

[Mark440]

Robert,
Currently, the belly is fully sealed with all of the duct work just laying on the ground except where it goes up to the floor registers. I envision coming off the "T", going out in each direction to make a 90 degree turn and then off of each elbow straight down each side. (There are four registers on each side).

I'm assuming this ducting material is aluminum. If I understand correctly, you suggest wrapping it with a moisture barrier and insulation? Also, due to the overall length, I am assuming I have to add some type of hanging support structure to support the ducting.

There is plenty of room under there to work (probably 3 feet in most parts) as the home sits on some sloped terrain. With the spring coming I can probably be with out A/C or heat for a few weeks.

Is this really something the proverbial weekend builder can accomplish?

PS - due to all the mess under there and I am sure a host of leaks, my heat bill is hitting over $300 a month for a 24x48. Yeow!

[Robert]

Hi,


Whether you can DIY depends on your abilities, it can be done if handy enough.


With a doublewide, you should have two metal aluminum trunklines down center of each half.


They should be up inside belly along with all takeoffs from trunks to registers.


Only thing that should be below the belly is the cross-over duct to join the two trunks.


That is often found laying on the ground amounst wads of duct tape.

If yours differs, it has been modified most likely.


Main thing is ducts have to be same size as there now to maintain specs for the duct according to design of unit.



Thanks,
Robert