I am installing a tile floor in a bath room, there is what appears to be a cold air return. This is open to a unconditioned crawl space, and you can see the back of the outside log wall. Can I seal this up? RussR
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Your info is a little sketchy...
What do you see when you go down in the crawl space? Maybe a duct laying on the floor that is supposed to be attached to the hole you have in the bathroom floor? I'm assuming there is a HVAC system or at least duct system in the CS? Are there returns and supplies in most of the other rooms of the house too? Does this bathroom have a supply in it too?
There is a heat vent with duct work. There is no duct work for the cold air. It is wide open to the crawl space. There are no cold air returns in this part of the house, all of the vents are open to the crawl space.
Somrthings broken here
WAtch out for live wires...plumber three blocks over from my house got electrocuted on Thursday. Details are sketchy at this point.
Based on what I think I'm hearing you say, your crawlspace is the return air plenum. This used to be an accepted method. That was when heating fuel (Natural gas, fuel oil etc) was cheap. I have run into it a couple of times. I have an old Manual "J" HVAC manual that explains how to install that type of system. Either run return air ducts from the HVAC unit to each of the existing openings,(which is best) or close off the existing openings and create one centrally located return air.
Another thought. Are you sure that these openings are return air. It is possible that they are supply air. Is your HVAC unit an up-flow or a down-flow? Do you have side wall or ceiling supply registers in each one of the rooms? If not, then the existing opening could very well be supply air. This also used to be done.
Thank You! The house was built in 1951. The air return idea seems to fit. The actual heat vents are at floor level in the walls (actually the inside walls) and the return vents are on the outside walls (in the floor at the wall)
Joist bays used to be 'panned' - they had sheet metal tacked across for returns. Your condition is *worse* but you might check to see if sheet metal was simply ripped down (nail holes, etc.).
Jeff
By todays code, you shouldnt have a return air in a bathroom. It introduces moisture into the rest of the building. Seal it up.
Family.....They're always there when they need you.
Do remember that bathrooms are not supposed to have air returns.
Supply registers near the inner "core" and returns on the perimeter was the setup when we used gravity furnaces - we reversed that arrangement when we went to forced air.
OTOH, in my area I've never seen a gravity furnace in a crawl space.
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