Basement Sub-Floor Using Sleepers - Need Some Pointers

[oldpilgrim]

Thanks. Interesting you put the plastic over the PT sleepers. That would avoid penetrations, just not sure what the long term result would be for the PT in my case given the high evaporation rate now.

check the specs of the mfg of the PT. Most PT is/was rated for 40 years of ground contact. I suspect it would be more in this situation, with no bugs, etc.

I know mine will last longer than me.

 

[dstig1]

Please read this before proceeding. Some of the suggestions here may have "worked" but I wouldn't trust them... This very directly applies to your situation.

http://buildingscience.us7.list-man...ae00e415fc8ed4a431&id=d10a732215&e=608a568f13

 

[oldpilgrim]

that whole article is about putting flooring directly on the concrete and has good advise.

But using the method I used limits wood contact on the concrete to just the PT sleepers. In my case there was only an occasional moisture issue on the floor. I would never put wood in any area that was prone to actual surface water.

 

[dstig1]

You may have misconstrued the article. It is not about putting wood flooring on a standing wet floor. If you have that going on, you have no business putting wood down at all, no matter what you do, until you fix the water problem (if possible). It is about the nature of concrete - it is porous, loves water, and will transport it long distances in amounts that will ruin wood (but not necessarily be visually noticeable otherwise). I would never recommend putting a wood floor over a slab that has had "occasional water issues". That is seriously asking for trouble. If you have that level of water trouble, the wood is not going to hold up as the wet concrete will create a high humidity environment below the wood - in contact or not. If you did this, and it has held up, you got lucky or conditions changed to keep the slab dry.

 

[Hiltz]

I have to agree with the posters who advise against trapping the moisture between the concrete and your new construction. You are asking for trouble. Mold ,mildew, no matter what your solution is against these problems the moisture problem will always be there. If you cannot stop your concrete from holding moisture you should find another flooring solution.

 

[BuilderML]

If i had to do what you want to do. Cover a slab with plywood. Not something i would like to do. Here is what i would do. #1 make sure no wood ever comes into contact with the slab or your foundation walls. No sleepers. No plastic. Lay down a layer of 2" T&G rigid foam over your slab. Tape all of your seams. Install your plywood over the rigid foam screw down plywood with tapcon screws.The foam will act as a brake not allowing your plywood to wick moisture out of your slab,provide insulation and help with leveling. Use floor leveler only in spots that really need it. Good luck. Also make sure you clean your slab very well not leaving behind any organic matter before installing your foam.

 

[CHDinCT]

Well, haven't posted back in a while since I've been going round and round on how to approach this. I corresponded with one of the floor leveling mfg's and was told, as expected, that I'd have to grind off the remaining epoxy paint, then put down a latex sealer/binder before using the leveler product. As an experiement, I bought a 4" concrete grinding wheel and tried grinding off some of the high spots/epoxy paint. It actually went fast, but wow, what a dust storm. Looked into renting a walk behind type grinder, but that was going to run around $250 for a day since you have to buy $155 worth of grinding wheels on top of the $80 rental fee. I guess they don't rent the consumables with the machine. So, grinding is out given the cost plus all the dust. I have my shop on the other side of the basement which I"m not putting a subfloor in, plus there's a lot of "stuff" down there still that would all get caked with cement dust.

So, I was going to just put down plastic and then 1x4 sleepers, level the sleepers using shims, put rigid foam in between the sleepers, then 3/4" T&G OSB subflooring. I am using pocket holes to screw all the sleepers together to make a monolithic frame with the hope that I won't have to Tapcon or Ramset the wood into the concrete in too many areas. I also hammer drilled out the high spots around my lolly columns and one/two other spots that were just way high. That was the plan until yesterday when I just wasn't feeling comfortable using the plastic to cover what will slowly become damp concrete.

So, I had looked at a product called Platon but wasn't going to use it. Changed my mind yesterday and quickly ordered 700 SF from Menards since no one sells it locally. Should be here mid next week. Platon has a dimpled side which goes down against the concrete floor to let it breath. The dehumidifier should pull out any moisture that accumulates under the membrane. In the mean time, I'm proceeding to "frame out" the floor and will mark each piece and remove it to put down the Platon once I receive it. Plus, all the PT wood is damp and I need time for it to dry out. Don't want to cover it up with all that moisture in it.

Link to Platon membrane: http://www.menards.com/main/buildin...laton-flooring-protector/p-1351809-c-5710.htm

Some pic's of where it stands now. Last pic is of my shop area, which is not getting covered (thank God given all the crap over there). Again, plastic is coming up as soon as the Platon arrives.

 

[fhdesign]

It looks like you have a ground water problem outside your foundation, it may be a good idea to have the footing drains inspected again by local contractor, they should have insight to ground water conditions in your area. You can also have a plumbing company inspect the footing drains with a camera, this will tell you if the are broken but probably not tell you if they were installed incorrectly. If the footing drains were installed just slightly too high or if they can't discharge the water your moisture problems will continue.

 

[CHDinCT]

It looks like you have a ground water problem outside your foundation, it may be a good idea to have the footing drains inspected again by local contractor, they should have insight to ground water conditions in your area. You can also have a plumbing company inspect the footing drains with a camera, this will tell you if the are broken but probably not tell you if they were installed incorrectly. If the footing drains were installed just slightly too high or if they can't discharge the water your moisture problems will continue.

Hmm, that's a thought. My issues seem to be in one corner near the door to the bilco doors. Could be some blockage there. Never get standing water there, but it does seem there's more water under the slab there than elsewhere. Not sure how the footing drains could be accessed without digging. There is an exit pipe on the far side of my driveway, but it's 50 feet from the opposite side of the house, so it would be a long snake to get to the back corner if it could be reached.

 

[dave1949]

Hmm, that's a thought. My issues seem to be in one corner near the door to the bilco doors. Could be some blockage there. Never get standing water there, but it does seem there's more water under the slab there than elsewhere. Not sure how the footing drains could be accessed without digging. There is an exit pipe on the far side of my driveway, but it's 50 feet from the opposite side of the house, so it would be a long snake to get to the back corner if it could be reached.

If you have the slope and space to work with, you could just run a new foundation drain line from that bilco door area -- on that side of the house. It probably wouldn't be a lot of digging to expose 10' of trench by the footer on each side of the bilco area, redo that section and send it into the new drain pipe.