DIY Home Improvement Forum banner

What do I do with this?!

484 Views 4 Replies 5 Participants Last post by  3onthetree
It's my first post on the HVAC side of things. I'm the first to admit HVAC is out of my lane. The answer may be obvious. But I have no clue how to tackle this.

Situation: Unsure how to handle a 6" supply that fed a toekick register under the kitchen sink base cabinet.

Background: Remodeling my kitchen after a dishwasher leak cause a partial loss. Old cabinets had a toekick register. The was custom fabricated and the water mediation company damaged it beyond repair when they removed the cabinets. I'm laying a 2nd layer of plywood in preparation for tile before the cabinets are installed.

Assessment: It's a 6" 90 degree elbow that comes up through the subfloor. Terminates flush with the subfloor. It will terminate underneath the kitchen sink vanity.

Problem: The cabinet installers said one cost effective option is to caulk the cavity under the kitchen sink base. This would prevent warm air leaking into the cabinet. Then cut out a toekick register.

I'm open to that option but there's a large gap between the subfloor and 6" duct. I don't want warm air pushing back down into the laundry room below. I could block off gap from below easy enough.

However, is there some boot or flange I should be installing over that 6" crimped end? It's held from below with a metal strap. I browsed Home Depot and didn't find any part that would address a situation like this.

I'm at a loss and want to get 2nd opinions before I install the plywood underlayment.

Thanks in advance boys!


See less See more
1 - 5 of 5 Posts
I would take the elbow off and replace it with a 6” round to rectangular duct 90 degree adapter. 6” round is is about 28 square inches. A standard size rectangular is 2x12 which is 24 square inches. Bring it through the floor as 2x12 rectangular. You can cut a perfect hole in your new layer of plywood to keep mice from finding the hole. Install a 2x12 short way elbow and a piece of 2x12 duct to come through the center of the kick plate. It will take a little finessing to get the cabinet in with the duct through it. Then put a 2x12 diffuser on the kick plate.
QED (quite easily done)
Or just cut a hole in a piece of plywood and nail it down.
Since that the affected part of the kitchen is stripped down to subfloor, can you move the vent so it doesn't terminate under the cabinet?

Or get another custom fabricated register?

You can also seal around the vent if needed.
I also do not prefer using the undercabinet space sort of like a "plenum."

I would just put a piece of sheetmetal on top of subfloor to cover the square hole, popping the 6" elbow through it (a better method, used when the space is a "plenum," is to cut tabs in the elbow like a start collar to hold the elbow tight to the sheetmetal, but you have the crimped end, so would need to solid couple it).

***You can just buy a toekick duct and attach to your 6" elbow. Since your elbow is not placed dimensional for this, you would probably need to make an extension out of sheetmetal to extend to the back of toekick board.
Product Metal Steel Aluminium Roof

***You can also make a toekick duct out of a start collar and wall stack.
Box Rectangle Metal Wood Floor
Platinum Metal

***You can also buy an expensive ready-made flexible duct to fit under there.
Product Wood Floor Plywood Table
See less See more
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.