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Carpet question,

3904 Views 30 Replies 7 Participants Last post by  steiny93
I have a very dry basement since digging it out and putting in a drainage system. My question is do I need to put anything under the carpet padding cause I see here some put down plastic as a vapor barrier im guessing.
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please explain as I have never heard of this before ???
Well if you have electrical junction boxes and shut off valves for gas and water you must either make access doors which to me would look ugly and be in too many places. Another thing is my floor joist are very old and are not exactly level across. I know it seems to be making excusses but I don't think it's worth the it. One more thing if I ever need to run anything in the future I will be screwed due to the sheetrock ceiling. Now I am starting to think Hmmm is it worth it????:spend::spend::spend:
Well it's either you want to soundproof or not I guess ... you can shim the ceiling flat using whisper clips and hat channel ... access doors can be covered up with fabric frames and conduit can be run "in case" you forgot something ;)
Well it's either you want to soundproof or not I guess ... you can shim the ceiling flat using whisper clips and hat channel ... access doors can be covered up with fabric frames and conduit can be run "in case" you forgot something ;)
Started another thread due to this one getting off topic. I have a lot of this metal channel that is shaped into a hat. I guess that what your saying,just have to level it off with shims and drywall.
About the vapor barrier under the carpet...

What happens in warm weather is the moist air goes to the lowest place in the house (the basement) and can condense on cool surfaces, like basement floors. It might not appear as being wet, but the moisture is there. Then there is moisture vapor that comes up through the concrete.

What happens when there is carpet and underpad (without a vapor barrier) on the concrete is that over time it will get moldy underneath. It might take many years for it to get bad, but it will happen. The mold is actually eating the underpad and carpet and the spores that it releases are very bad for you. It will make your HT smell like a dirty gym.

Anything that touches concrete walls or floor needs to have a vapor barrier between it and the floor/wall or has to be moisture/rot resistant (ie: pressure treated wood). That includes your wood framing, wood flooring, carpet and laminate flooring. That is written in building codes everywhere.

It's actually best to have insulation, sleepers with sill gasket under them, then vapor barrier then subfloor (insulation on the cold side), but that can increase your build costs quite a bit.
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Thanks for that detailed reply. I will put down 6mill plastic under the padding. Definetly makes sence to do so, as far the rest I am good to go in the framing with PT as the sill around the basement.
Really 6 mill under the pad?
If you put the vapor on top of the concrete aren't you going to get condensation between the concrete and the vapor? And isn't that going to give you a mold issue?
Mold needs 2 things to grow: food and water. When sandwiched between the concrete and a vapor barrier, it has the water, but not the food. Drywall, carpet padding, etc *could* be food if the moisture could get there. So you are okay trapping it to the concrete.
i would have to disagree,
your concrete isn't going to be 'food free' and you will have voids / tears / holes / etc in your vapor barrier where you will get that condensation against the pad

if you get condensation between the concrete and the plastic you will get mold in the pad

iy inlaws own a company that does commerical flooring, lots of commerical flooring for the past 40 years, i just ran this by there local job sup, he shared my opinon and had seen tearouts where the previous install did as you suggest. the removal was terrible nasty due to all the mold

granted, your results may vary
Here is another option, Install foam insulation tongue and groove type onto the floor tape all seems. Then install on top of that tongue and groove 3/4 ply wood screw down with tapcon concrete screws then carpet padding then carpet. This method is exspensive and you do loose some headroom in the process.:spend:
i believe the root of the issue is where the vapor barrier resides and how that will affect the neighboring materials

ie, if the barrior is beneath the concrete then all is fine as the sand below the concrete doesn't care. But when the barrior is in a location that can get the mold train moving bad juju happens

in the above scenario you'd just move the barrior to a concrete vs. insulation space, i would guess that the insulation would wick the moisture into the plywood and cause the same issue
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