Ducting thru drywall ceiling

[CannaRed]

What do you use to properly duct thru a drywall ceiling.

Just cut a 6"ish hole and run it through, then try to seal?

Or is it best to install flanges on each side, to attach duct?

 

[Smokesteve]

A hole with some nice flexible caulking sealing it is a simple clean way.

 

[ElGato]

Just cut a 6"ish hole and run it through, then try to seal?

this^^

if using flex duct you can cut the hole kind of snug and the flexibility of the ducting will seal any gaps. If using ridged duct, try and cut the hole exactly the size you need and seal with some latex caulk on the top side.



mj

 

[Bobby Boucher]

I would run rigid through. Running flex through is an eyesore, imo.

Not to mention, using rigid ducting wherever possible puts less strain on the extraction fan..

 

[GOT_BUD?]

I cut my hole then install one of these. Then I use rigid or flex depending on my needs.

Reach your hand through the collar to bend the tabs over to hold it in place, then tape or caulk it up to seal.

 

[Bobby Boucher]

That starting collar is great for a start or an end on a plenum box. If you stuck it in into your drywall/subfloor or drywall/stud/drywall, you’d wind up pushing or pulling air from the subfloor or the space between the walls.

If we are trying to go through through, multiple levels, rigid duct, obviously. If you are trying to start or end a run through a space in the wall or subfloor, you could stick an air-tight “takeoff” there, backwards, in place of a starting collar, for the extra bit of length.

If you stuck this thing down from the upper level, it should make all the way through your subfloor with space left to affix your flex duct from the bottom without any hassle. That’s what I would do. For an end to a run, anyways.

I wouldn’t want to pump air into my walls unless it was very dry air, say from a run of cool tubes, and even then.. probs not. Done it, but..

Also definitely would not want to pull air from inside with walls. Done it, but..

 

[Oliver Pantsoff]

Make sure you dont run into any 4x4s when cutting the hole...

OP

 

[CannaRed]

Thanks everyone!

I have 6" insulated duct, but it is flex. Maybe I should get rigid then use the insulation off of the duct I already have.

I'm just going thru one layer of drywall. Duct out of tent, thru ceiling into attic, and back out again. I'll make sure to avoid the rafters.

 

[Zeez]

Rigid is much more difficult to use than flex. The flange Bobby recommended is the way to go. Use the pipe side of the flange for a template and cut the line with a drywall saw. Save the cutout in the attic for when you want to fix the ceiling.

 

[Bobby Boucher]

Yeah, working in an attic sucks, no matter which way you go..

I would be trying to avoid it at all costs. It'd have to be a some huuuge or very rapid moisture output (like a bath or shower) for me not to consider just trying to recycle the heat and humidity..

I keep a whole house humidifier in my bedroom that puts out 5-6 gpd on its own. My whole house is wood hardfloor and it sucks moisture up like it was never there to begin with, and then the heater dries right up like.... it was never there to begin with..

Too stoned for creative analogies, man.. Nap time.

I think if you were creative enough though, you could heat and humidify your whole house and save some money doing it.. if your winters are as cold and dry as mine, anyways, even with a big ass 20kw grow er some shit..

 

[CannaRed]

I'm sorry I wasn't more clear.

I'm running the duct thru the drywall into the attic and out of the attic into a small lung. Filter in lung draws all the hot stinky air and blows clean warm air to my living room. Helps a little on living room heating bill.

I'm not actually exhausting the air into the attic.

 

[sshz]

The best advice I can give is make it straight as possible........bends, dips, turns, etc. hinder the efficiency of the blower.