Hello everyone,
I'm new to this site, and was hoping to see if someone could shed some light on what I would need for a DIY duct project.
The house in from 1959, and has an original flat roof. Built above the flat roof is a slope shaped roof. There is no accessible attic space in the design.
We have a central AC system that provides air using 6inch & 4inch tube ducting to a few rooms, but its set up in a way to where the ducts are out of sight. Ideally, I would like to create a box style duct thats flushed with the upper wall/ceiling level, and possibly paint over it.

My only option is to install ductwork to run alongside the wall and flushed with the ceiling. I've seen this style of ductwork done in older homes in NY, and also some areas here in FL.
I'm not sure what I should be buying, or if there are prefabricated box duct sections. In all, I need to run about 50 feet of duct work. Getting through the walls is easy because its just drywall, and 2x4.

Any help would be super appreciated. With all this downtime, I figured I could try tackling this.

 

IMO you would want to use spiral pipe and spiral pipe fittings such as reducers as you get toward the end of your ductwork.

Schematic and example of parts.

If you want rectangular ducts you can use those too I suppose. IMO the spiral ducts look better. You see them all the time in commercial settings or in modern residential/condos where they are left exposed and are usually painted black like the ceiling is so they disappear.

 

Thanks for the schematic. Since I am flushing the ducting with the wall/ceiling corner, I would need to go with the rectangular ducting. Aesthetic wise, the spiral ducting wont look right in this case.
What would be the best place to go about buying rectangular ducting ? Home Depot, Lowes, etc ?

 

You might want to get prices from some HVAC contractors to at least fabricate your ductwork and possibly install it. Many HVAC contractors have the tools so they can make rectangular ductwork to the size & length needed. If you decide to do it all yourself there are many places that sell rectangular ducting so check around in your area for who has the best price and selection in stock. Keep in mind that once you start with a particular brand duct you may have to stick with with that brand so the pieces can connect so make sure that they have everything you will need.

 

Hi, are you planning on using sq ducts to replace the existing? I might consider round ducts and boxing them in up near the ceiling, JMO.
Geo

 

How would I box up a round duct though? Material wise. Running flexible duct would be nice, but I don't know what I would enclose it with. And what would be more cost effective. In all, it would be about 50ft in length. I would probably use a 8" flex duct for large rooms, 6" for smaller ones, and 4" for a bathroom.

 

Regardless of the shape of the duct, you'd usually use 2x4's to frame out boxes around the ducts. If you use flexible ducts, you can build the 2x4 'box' and pull the duct through. On top goes drywall.

Some people use 2x2's, but I find it's easier with 2x4's as you have less twisting and warping.