How do I cap off this duct?

[M6erfan]

So I have to remove this register and the connecting ductwork down below, preparing for carpet install in the master over the old hardwood. After the new master bath remodel, I'm left with this register in the walkthrough, it's gotta go. I know ZERO about HVAC and I'm unsure of how to remove the duct and cap it off. I am not moving it, I'm removing it altogether.

 

[larry4406]

Can you relocate it and make it a stack head in the right side wall where the vinyl floor is (and the over run base is)?

 

[rust in the eye]

If you weren't planning to already remove the entire run and cap at the trunk.
Given this is in a walkway I'd be sure to have a strong patch in the floor. If you can run a couple of scabs between joists to support it all the better. At the very least a big patch underneath glued and screwed. I'd also glue the topside patch bottom and sides.

 

[M6erfan]

Can you relocate it and make it a stack head in the right side wall where the vinyl floor is (and the over run base is)?

It's tile not vinyl (I won't tell my wife you said that ). And I suppose I could move it. My concern is having to go through the tile & subfloor and me f'ing it up. The register would have to be tight against the wall as the walkthrough path continues into the new WIC. But I think it's just simpler to remove the existing and cap it off. Maybe I'm wrong?

A couple more angles . . .

 

[larry4406]

It's tile not vinyl (I won't tell my wife you said that ). And I suppose I could move it. My concern is having to go through the tile & subfloor and me f'ing it up. The register would have to be tight against the wall as the walkthrough path continues into the new WIC. But I think it's just simpler to remove the existing and cap it off. Maybe I'm wrong?

A couple more angles . . .

A stack head is a wall register. Put it in the wall not floor. Position register about 1” above your base molding. Interior wall.

 

[M6erfan]

A stack head is a wall register. Put it in the wall not floor. Position register about 1” above your base molding. Interior wall.

Ha, told you I know nothing about HVAC. Thanks for the explanation!

 

[jack stand]

It's extremely obvious once you see what's under the insulation. You probably would be fine just prying up the register and cut a little piece of rigid foam to friction fit the duct and support the floor.
Taking as much of it apart as you like, then simply blocking the airflow is your target. This could be done (without additional metal) with "duct tape". Imagine that!

 

[larry4406]

Here’s how a stack head finishes out and what the roughin box looks like. I would not delete a heat/AC source.

Note the oval riser on the stack head so it fits in a wall.

 

[M6erfan]

It's extremely obvious once you see what's under the insulation. You probably would be fine just prying up the register and cut a little piece of rigid foam to friction fit the duct and support the floor.
Taking as much of it apart as you like, then simply blocking the airflow is your target. This could be done (without additional metal) with "duct tape". Imagine that!

I want to remove it completely and plug the floor like @rust in the eye describes.

 

[M6erfan]

Here’s how a stack head finishes out and what the roughin box looks like. I would not delete a heat/AC source.

Note the oval riser on the stack head so it fits in a wall.

Thanks! Why would I not want to delete it? Throw off the balance or something?

 

[larry4406]

I want to remove it completely and plug the floor like @rust in the eye describes.

Understood.

The stack head I showed used to be in the floor. We moved it to wall to add ceramic heated floor

 

[larry4406]

Thanks! Why would I not want to delete it? Throw off the balance or something?

Whomever did your HVAC originally thought you needed conditioned air at that location. Why second guess them when a wall register will do the same thing and get it out of the floor?

Yes balance and distribution impacts come to mind.

 

[M6erfan]

Understood.

The stack head I showed used to be in the floor. We moved it to wall to add ceramic heated floor

It's a good idea and I wish I had asked this question months ago before I insulated/covered the walls and installed the clawfoot tub along the wall where a stack head might go. I mean, anything is possible but it would be a TON of work and not sure it's worth all that effort. Also, the original walls in the bedroom are plaster over gypsum (1955) and I really would rather not get into them.

 

[M6erfan]

Whomever did your HVAC originally thought you needed conditioned air at that location. Why second guess them when a wall register will do the same thing and get it out of the floor?

Yes balance and distribution impacts come to mind.

I hear ya, I wish there was a good spot to put a register of any sort, and I'm afraid I'm a little late in the project thinking about it.

 

[larry4406]

Understood.

Ceramic floors tends to be cold. Deleting a heat source at a flooring surface which tends to be cold can make things worse.

Maybe you can relocate the supply as a cabinet toe kick register.

 

[M6erfan]

Taking a look, there is one possible spot in the bathroom to relocate it to . . .



For now though I need to get the old one out of there and get the floor prepped for carpet. I think relocating is something I can do at a later date, at this point it hardly matters when I do it.

Thanks for the advice and ideas.

 

[larry4406]

Taking a look, there is one possible spot in the bathroom to relocate it to . . .



For now though I need to get the old one out of there and get the floor prepped for carpet. I think relocating is something I can do at a later date, at this point it hardly matters when I do it.

Thanks for the advice and ideas.

That would be a good spot for a stack head.

Regarding floor register deletion, I recommend the following which is what I did:
- remove the duct from below and tape it off at a convenient location. Either capped off at the plenum or just taped off below deck while you ponder where to move this tap.
- take a piece of 2x10 or 2x12 and cut it to **** from the exterior band board and the first floor joist. Cut it snug.
- apply construction adhesive to this piece (scab) and push it tight to the underside of the subfloor centered on the register. Apply construction screws to attach this scab to the band board and the first joist.
- your hardwood should be 3/4” thick. Not sure your subfloor thickness. Cut a piece of (?) to fit the old duct rough opening with thickness to match your subfloor and hardwood. Apply some construction adhesive to the top side of the scab and screw the hole plug down. Screws are your friend vs shock/impact loads from a hammer. (I added screws top down from my subfloor but if there’s a chance you would ever refinish your hardwood floors I would not do it).
- cover with your carpet.
- deal with relocating/deleting the heat supply later.

Hope this helps.

I’m a fan of hardwood. We tore out all our carpet and put in real sand on sight hardwood.

 

[M6erfan]

That would be a good spot for a stack head.

Regarding floor register deletion, I recommend the following which is what I did:
- remove the duct from below and tape it off at a convenient location. Either capped off at the plenum or just taped off below deck while you ponder where to move this tap.
- take a piece of 2x10 or 2x12 and cut it to **** from the exterior band board and the first floor joist. Cut it snug.
- apply construction adhesive to this piece (scab) and push it tight to the underside of the subfloor centered on the register. Apply construction screws to attach this scab to the band board and the first joist.
- your hardwood should be 3/4” thick. Not sure your subfloor thickness. Cut a piece of (?) to fit the old duct rough opening with thickness to match your subfloor and hardwood. Apply some construction adhesive to the top side of the scab and screw the hole plug down. Screws are your friend vs shock/impact loads from a hammer. (I added screws top down from my subfloor but if there’s a chance you would ever refinish your hardwood floors I would not do it).
- cover with your carpet.
- deal with relocating/deleting the heat supply later.

Hope this helps.

I’m a fan of hardwood. We tore out all our carpet and put in real sand on sight hardwood.

Great tips Larry, much appreciated.

Our whole hose is original hardwood floors and we had them refinished and actually replaced them in the kitchen because they were ruined with old mastic. The area I show in the pics where the register is used to be a closet, an add-on at some point in the past. That area of the floor is in pretty bad shape. So it'll be covered, plus we like the comfort and sound control that carpet over a good quality pad will offer in the main bedroom.

 

[M6erfan]

@larry4406 I'm going to try and tackle this tomorrow. Just to clarify, should the 2x12 should be flat (face) against the subfloor, or on edge like a joist?

 

[PoorUB]

Whomever did your HVAC originally thought you needed conditioned air at that location. Why second guess them when a wall register will do the same thing and get it out of the floor?

Yes balance and distribution impacts come to mind.

I hear ya, I wish there was a good spot to put a register of any sort, and I'm afraid I'm a little late in the project thinking about it.

Are you prepared to have a hot or cold area, depending on the season, in the house?

Any other registers in that area?

I would consider moving over to the vinyl, and rotate it 90 degrees so it can be tucked against the wall. Perhaps it might be worth while to pay and HVAC company to relocate it?

 

[M6erfan]

Are you prepared to have a hot or cold area, depending on the season, in the house?

Any other registers in that area?

I would consider moving over to the vynil, and rotate it 90 dgrees so it can be tucked against the wall. Perhaps it might be worth while to pay and HVAC company to relocate it?

Perhaps. Again, I can do it anytime in the future so not an immediate concern. Yes, there are other registers in the room.

 

[PoorUB]

Perhaps. Again, I can do it anytime in the future so not an immediate concern. Yes, there are other registers in the room.

True, the basement is wide open.

Cut off the insulation, and you should see how the duct is assembled. It appears to be round duct, so just a matter of backing out 3-4 screws and pulling the sections apart. I would leave the run in place and buy a cap to fit the duct and cap it off just in case you decide you need more heat or cooling.

Pop out the register and it should have a couple nails through the side of the tin into the sub floor.

Once you get it removed sealing up the hole is the tricky part, at least to make it solid. I might consider laying a 2x6 flat up against the subfllos from underneath, right below the hole, and a couple 2x4 blocks under each end nailed into the joist, then fill in the hole with 1x4 material. Some floor leveler to fill in the voids and level it out.

 

[M6erfan]

I just went downstairs and peeled back the insulation. Yep, looks straight forward. One possible snafu, all the flooring nails coming 3/4" inch through the subfloor and will impede any board laying up against it from underneath. Ocsillating tool with carbide blade?

 

[larry4406]

@larry4406 I'm going to try and tackle this tomorrow. Just to clarify, should the 2x12 should be flat (face) against the subfloor, or on edge like a joist?

I just went downstairs and peeled back the insulation. Yep, looks straight forward. One possible snafu, all the flooring nails coming 3/4" inch through the subfloor and will impede any board laying up against it from underneath. Ocsillating tool with carbide blade?

Yes the 2x12 should be flat (face) against the subfloor bottom. You can add a vertical joist like piece under it for added support if you want as you indicated this will be a high traffic area.

Yes you need to trim all of the flooring nails flush first in the region where the flat face 2x12 will go. Oscillating tool with a bi-metal blade will be ideal.

 

[mogandave]

My oscillating tool takes forever to get through nails. I would use a 4" grinder.

 

[M6erfan]

So, I got after it this afternoon. I basically followed you guys directions and it went pretty much without a hitch. @mogandave was absolutely correct, my OMT took forever to get through a nail and ate up a new carbide blade pretty fast. I switched over to the angle grinder and much faster . I terminated the duct with a duct cap I picked up this morning.

Glued and screwed the 2x10 (that I had) then ripped a piece of 2x for the plug and glued and screwed that too. The plug is about 3/16" shallow so I'll get some self leveling patching compound and fill it in.

Thanks guys, really appreciate all the advice!

 

[mogandave]

Looks good!

Make sure you sweep/vacuum-up the grindings carefully or they can stain the floor if they get wet and rust.