Tile on basement floor

[AMontemagni]

I have been told that in order to tile a basement floor, I should first put down a moisture barrier (3 mil plastic) and then 1/2" tongue and groove plywood and then tile over that. The plywood will help to make the floor more level. Would you suggest this? Or a different method?

Keep in mind that my floor currently is painted (with cheap paint by the previous owner), so it is pealing up everywhere.

What do you think?

[floorman]

No,that would be a sleeper system and i don't think that you would need one in this case.
What you do want to do however,is to take some of that plastic and cut it into 1foot x 1 foot squares, you will need 3 for the first 1000 square feet of floor space to be covered and then another 1 for every 500 feet of floor to be covered,now take some duct tape and tape those top the floor sealing all the edges real good,scatter them around the area so you will get a good portion of the floor covered to get a good reading,now let sit for 24 hours and see if the slab under the pieces of plastic are damp or wet,if so then you want to see how much moisture is in the slab and will need a calcium/chloride test to find that out.
If you don't do this then you may end up redoing the floor at a later date,so take the time to do this now and it will pay off later.
Do that and then get back to us and let us know what you come up with [8D]

Floorman
floorlayers union local 1310

[AMontemagni]

floorman, thanks for the reply...why would I cut up the plastic into squares? when I have a 3'x100' roll. Wouldn't I just lay it out as it is and tape the seams?

Also, I forgot to mention that I already know that the floor is damp, mostly in the summer due to a high water table in the area.

That is why I was thinking of putting the 3 mil plastic down, tape all the seams, and then put down the plywood. My thoughts are that the moisture would stay below the plastic, keeping the plywood intact and dry.

But also one of my questions is if I did that method, the plywood would not be screwed/glued to the floor. Is there a chance that it might bow up and have a space between the plastic and plywood? Or would the weight of the tile keep it all the way down?

[floorman]

Cutting it into squares was a way to determine if moisture was present or not,since you already know the floor is wet then forget that,you also do not want to cover the floor in plastic cause then there would be no way for the moisture to dry out and cause mold/mildew problems.Depending on how much moisture there is coming up through the slab will determine which route you will need to take.Get a calcium /chloride test and see how much moisture is present,you can set tile on wet slabs but there is a cut off.
If there is too much then you would need a sleeper system but the way you are trying to go about it is wrong so do that test first and let us know what you come up with[8D]

Floorman
floorlayers union local 1310

[AMontemagni]

floorman, ok I will try that calcium/chloride test and let you know. Also, what is a sleeper system? Where can I find out more information about it?

[floorman]

Sleepers are when you would take 2x6 or 8,10 and nail them to the floor laying flat and then plywood over that.You usually want to do that with wood installations below grade or when you know that there is a moisture problem to keep the flooring from getting any damage from the moisture[8D]

Floorman
floorlayers union local 1310