Looking for rectangular paintable ductwork that looks as good (and works as well) as boxing it in with drywall.

October 5, 2008 9:12 AM

We just boxed in with drywall a round 5" heating duct, running from floor to ceiling in the corner of the living room. Because of some odd features of the room, this took up more space than it should. What I'd really like is to replace the duct (and drywall) with a paintable rectangular duct running up the corner of the room, that would look just as good as drywall. This would have to be rugged enough to withstand small children playing in the room (e.g. not dent like typical metal duct). Does this exist?

When I search for paintable duct, I get stuff that's intended to run across the ceiling, not be good as a wall. (e.g. I suspect that the metal duct would not only dent, but the paint would flake off when it did dent).

FWIW, the duct was already there and the renovation we just did made the box much smaller than it had been, but I want more.

The duct will have to make a 90-degree turn into a round duct immediately above the ceiling.

posted by winston to home & garden (5 comments total)

How about building a duct of wood instead of metal?

Maybe air from the heater is too hot for plywood but solid wood can take highish temps. Or maybe it would burn the house down? Anyway, that's what I've been thinking of doing here, where I have a similar problem. I just haven't researched the temperatures yet.
posted by airplain at 10:20 AM on October 5, 2008

Airplain's answer confirms my thinking - why not put in a metal duct and then put a wood veneer over it?
posted by Inspector.Gadget at 11:39 AM on October 5, 2008

Does it have to be square, i.e. look like "wall"? If you are primarily worried about its durability, you could swap it out for a large-diameter schedule 40 pipe, which is then paintable and pretty much bullet-proof.

If you want build a square "duct", you're basically building a plenum. There are building codes that govern what materials can be in a plenum (for exactly those concerns about ignition, as well as giving off toxic or dangerous fumes in case of a house fire, which are then distributed around the house by the ductwork system, making a localized problem into a larger-scale problem. It might be worth a call to your local building code official -- they are generally very helpful when dealing with homeowners, as they recognize how rarely people try to "do the right thing".

My recommendation? Don't muck around with the plenum issue at all. Build a plywood "L" that fits into the corner of the room tightly around the duct (about 6"x6" inner dimensions), of 3/4" or 1" plywood, and if necessary use a continuous glue/screw block on the inner corner to hold everything together. Also fasten blocking to the walls, about 6" out from the corner, such that you can fit the plywood "L" into the corner to conceal the duct, and then screw into the blocking attached to the walls. Then you can drywall over that (or even just spackle over the plywood?) and it will be as small as feasible, very sturdy, but also safe and code-compliant.
posted by misterbrandt at 7:07 PM on October 5, 2008

If you'll post a photo somewhere of what you've got going I can give you a better idea of how to resolve it, that whole 1 picture 1000 words thing, right? I come from a construction family, I've done most all of it, but it all started with my fathers heating and A/C business. I've banged out lots of duct work, tons of it (yep, literally tons of it -- we'd go to the supplier and pick up 28 gauge and 26 gauge and, if I recall correctly, some heavier than that, for really large ductwork), more than I'd care to remember, but I remember it anyway.

The people recommending a wooden plenum -- hey, that'd be fine, except for the part about burning your house down and stuff (probably not, actually, though if an inspector ever saw it he'd jump up and down and hoot and bellow, excitedly), but how are you going to connect at the top and bottom to the existing heat run, and not lose all your flow -- you're not going to. Also: Going from 5" round to a larger space and then back to the 5" round -- you're going to lose air flow, bigtime. (You're already losing lots of air flow with that 90 degree elbow there, truth be told.) An enclosed area such as they are suggesting is fine for a return air ie air being sucked back into the furnace to be heated again and shot back into the house. But not for a supply.

Regardless all that, the fact is that if you give me a photo I bet I can show you a way to box it in tight, and I do mean tight, the sheetrock right up against the round pipe. Along with being a tin-knocker I spent plenty of years as a carpenter, both residential and commercial, both wood and metal studs and acoustical ceilings etc and etc and etc, and when I ended up running commercial work I always ended up with the highly detailed jobs, and the reason behind that is that I can figure out anything and do it right and still bring it in under budget blah blah blah. I can build it.

Post a photo or five to let me see what you've got, after you've blown out what you've done, or maybe even as you do so, so's I can see why you didn't bring it closer than you did when you did it the first time. It'd be nice if I could actually see it; maybe for some reason it can't be sucked any closer than what you've done already -- that'd suck, you blow the whole thing down just to rebuild it. In any case, send me a pm or post out here on this thread where the photos are linked, I'll take a peek and let you know what I see and what to do next.

Boy oh boy, building stuff over the inter-tubes -- this is so gonna rock!
posted by dancestoblue at 2:55 AM on October 6, 2008

Hm. As I said, it's already boxed in -- and I didn't take photos before we did so. (and I want to have a plan before I decide to tear it apart again :-)
posted by winston at 10:28 AM on October 7, 2008