HVAC ducting and cabinet reconstruction

This is actually a different topic entirely from my other HVAC thread.

So my garbage disposal died too. It threw water all over the bottom of the cabinet. The bottom of the cabinet looks like this

And problem #1 is that I need to replace it. Other than leaving a small lip all around the perimeter, are there any tricks to cutting for those pipes, or is this really just a 'cut a slot and fill in the back once the new cabinet floor is in place' type of things?

Problem #2 is that I now realize that the HVAC outlet is under the cabinet. Let me clarify.

I have this grate:

But it's not actually connected to anything. There is a rectangular hole in the subfloor about 4" inboard and 6" to the right from the centerline of the grate. I should probably connect these two, eh? How do I do that on the cheap? I don't really want to fabricate a new steel duct here. So problem #2 is how to make a cheapo duct to connect the two things such that I am not heating and cooling the bottom of my cabinet and the outside wall.

you could shut off the water and cut the pipes and reconnect them with a coupler once you make the new bottom and drill neat round holes and slip it over them versus making slots.

for the duct, you could make it quick and dirty out of a 2x4 and the scrap of plywood that you'll have left over from the new cabinet bottom.

A duct elbow will be about $15 but it's up to you to decide if time or money is more valuable on this job.

I would cut the lines and drill the holes too, but that's because if I made slotted holes it would always bother me and I would be compelled to fix it.

Ojala wrote: A duct elbow will be about $15 but it's up to you to decide if time or money is more valuable on this job. I would cut the lines and drill the holes too, but that's because if I made slotted holes it would always bother me and I would be compelled to fix it.

I don't think I am going to find an elbow to make this work off the shelf. It's maybe a 4"x6" hole in the floor going to the grate which is maybe 2"x8" and it's offset by 6" or so.

Dont worry about it, the gap under the cabinet serves as the duct, that is the way most all of them are done.

Don't worry about the vent. But if itbugs you that much, bend up some luan and make a duct.

Looking at the cabinet, it almost looks cosmetic only. If its not, cut out the rotten part. Use as template for a patch panel, and skin the entire repair with a piece of luan. Add some contact paper, and no one but you and tunawife will know.

Also, garbage disposals are evil.

In reply to tuna55:

There's actually no need to connect the register to the hole in the floor. The cabinet base will just act as a plenum. If it is a return, then there is probably just sheet metal nailed across the corresponding joist space below, and the air handler will suck air through the base of the cabinet into the return "duct" that is formed by the joists and sheet metal below. If it is a supply and you absolutely feel the need to do something, just make a little 2-leg fence out of scrap lumber that is ripped to the same height as the blocking that the cabinet floor sits on and close it off to the kick plate and the side of the cabinet.

Duke wrote: In reply to tuna55: There's actually no need to connect the register to the hole in the floor. The cabinet base will just act as a plenum. If it is a return, then there is probably just sheet metal nailed across the corresponding joist space below, and the air handler will suck air through the base of the cabinet into the return "duct" that is formed by the joists and sheet metal below. If it is a supply and you absolutely feel the need to do something, just make a little 2-leg fence out of scrap lumber that is ripped to the same height as the blocking that the cabinet floor sits on and close it off to the kick plate and the side of the cabinet.

I'm doing the latter portion of what you said here. Good call, thanks for the advice, guys.

Dusterbd13 wrote: Don't worry about the vent. But if itbugs you that much, bend up some luan and make a duct. Looking at the cabinet, it almost looks cosmetic only. If its not, cut out the rotten part. Use as template for a patch panel, and skin the entire repair with a piece of luan. Add some contact paper, and no one but you and tunawife will know. Also, garbage disposals are evil.

It's definitely rotten. It has been leaking for a while. I have a scrap piece of 3/4" OSB that will work fine for a false floor. Contact paper? I was thinking those sticky vinyl tiles.

No way in the world am I cutting into three perfectly non leaky pipes for the cosmetic benefit of not having a slotted floor. I'll make the patches and then vinyl over them.

The cheap duct route would be duct board and alum. tape, but like everyone else is saying, it's not really necessary. Think about where the most amount of heat is coming and going? Through the exterior wall. There's probably some cooling load (heat coming from) your stove in the middle of summer, but it's not a big deal unless you are having an actual temperature problem in the kitchen.

I got a Mercedes rubber trunk liner from the GY and used to cover the bottom of that cabinet in my house. Its got a lip to trap liquid that spills, it comes out easy for cleaning if need be and if I remember correctly the counter guy and the Pick-N-Pull did not even charge me for it.

Pulled it apart last night. It must have had a leak or two for a while, the bottom of the cabinet was soaked through, the vinyl on the floor (original floor covering) looked deceptively good, but the luan underneath was moldy and the subfloor was wet.

Happily it was only on one side, so I bleached it, dried it, and will Killz is before I reconstruct the cabinet.

Owning a home can be such a bitch can't it?

I should have never become a homeowner.

Any structural rot?

And please tell me that the garbage disposal is going away. I have never seen one that didn't cause problems.

Dusterbd13 wrote: I should have never become a homeowner. Any structural rot? And please tell me that the garbage disposal is going away. I have never seen one that didn't cause problems.

The Subfloor is OK, just wet and moldy on top. I bleached/scrubbed it and left an air purifier on full blast all night and it's dry now. It was dry underneath in the crawlspace. Now I get to reconstruct the cabinet.

I glued in (liquid nails) enough plywood of the right height to serve as a bridge for the two pieces (the floor had to be made of two pieces) and for ducting, and threw this together last night.

Eagle eyed readers will note that there is rubber between the now-straight discharge elbow and the lateral pipe. Yup, that's leftover fuel vent tubing from Tunatruck. I could go through the effort of purchasing the appropriate PVC elbow, cutting it, lengthening the lateral pipe and using a pressure connection, but it's going to work perfectly this way and be way easier to maintain.

I added the outlet for the disposer (sorry Michael!) too. I found that the flexible conduit that the installer used was just jammed against the back of the cabinet, there was not enough of a hole for it to actually protrude into, so I fixed that too. The next step is to Killz the floor and then vinyl tile it all.

Weird. I have the same goofy undersink vent arrangement at my house, except when we moved in there wasn't even a grate to cover the outlet.

I am with Duke and his plenum theory. It's a HVAC vent, not an air intake for a high performance tuna truck. Don't over think it.

bgkast wrote: Weird. I have the same goofy undersink vent arrangement at my house, except when we moved in there wasn't even a grate to cover the outlet. I am with Duke and his plenum theory. It's a HVAC vent, not an air intake for a high performance tuna truck. Don't over think it.

Eh, it was plywood I already had and 5 minutes of cutting. Now I feel better since I am not heating and cooling the exterior wall and the bottom of the cabinet.