Hi everyone, I'm new here, and joined because several years ago my husband and I stupidly paid to have Armstrong VCT (vinyl composition tile) installed in our basement. This was in summer 2010. Now, I am pregnant with our first baby, and we are freaked out about the off-gassing and horrible stuff used in these tiles. The basement will be used for a playroom and the baby will spend a LOT of time crawling and playing down there. We're ready to correct our mistake by ripping out the nasty VCT and installing something different, even though it is expensive. We would much rather do that than increase our son's risk for autism and other disorders (the list of possible disorders created by the nasty materials used in VCT, while I realize it is scientifically inconclusive, seems long and I'm not willing to wait for science to catch up and for the government to protect us from these harmful chemicals). However, it's not easy to find something that is eco-friendly that works below grade. Because it's a play room, we don't want to go for ceramic tile. That's far too hard for a baby's play area. I would assume that, even though we don't have a "wet" basement, it is damp like most basements and so products like hardwood, cork, and real linoleum won't work. I am not interested in carpet. I have read online that there are some laminate flooring types that are much better for IAQ. I'm willing to go that route or any other route that would be appropriate for a baby and a basement.. reasonably moisture resistant, and not as hard as ceramic tile. Can someone help me?

does the basement ever have standing water or does it have leaks around the edges where water comes in?

Hi Bob,

Not since we have lived here (big knock on wood). Our sump pump isn't even operational. However, the previous owners installed a B-dry system at some point, which makes me wonder whether there was a problem at one time.

We also live in an area where most people have problems with water in their basements at some point, but we are up on a hill (our neighbors have also not reported any problems, at least the ones I have asked about it).

Our floors also aren't super level, if that makes a difference... they have peaks and valleys in them. They were made somewhat more level before the VCT was installed, but it's not perfect.

Also, we were thinking we'd leave the VCT in the laundry area to save money. But is that a mistake? I'm not sure how much the off-gassing would travel from room to room. The laundry room will have a door (we're planning to install one to keep baby out of there anyway since that's where the litter box is), but it's part of the basement.

How about cork?

There are several flooring products - sorry I do not know the names of any of them - which have a plastic ribbed bottom so the finish floor is off the damp concrete. I believe it does not fasten to the floor, but will basically "float", similar to laminate floors. Before that, though I recommend dealing with the moisture - dampness is not a good environment. Put down a heavy - 10 mil - plastic, overlap the joints and tape the seams. You will probably have to order the poly from a lumber yard (a real one, not a HD) and have them recommend a good tape that will stick to their product. I recommend SIGA Wigluv or Sicrall which can be ordered from maine Green Building (they can recommend the right one) - the acrylic adhesive sticks to everything and is non toxic. then put the floating floor over that. -Bob

By damp, I really just mean that we run a dehumidifier in summer. Our walls aren't insulated down there, so it tends to be cool and somewhat humid in the summer. I'm not sure the dampness is coming from the concrete floor.

Jonr, would you recommend a floating cork floor or a gllued floor? Floating I assume?

"I'm not sure the dampness is coming from the concrete floor. "
I've been building houses for many years, and for a long time built houses with cool, humid basements, probably similar to yours. until I realized that the moisture is coming from the ground - through the porous concrete - and that we have the means to insulate and damp proof the space. Now the homes I build have dry basements which are much more comfortable, heat easier and keep the whole house at more comfortable levels of humidity.
It is harder to retrofit an existing house and without dealing with the walls so you'll still have some moisture coming into the basement through the concrete, but sealing the floor will cut down the moisture levels and give you a much more comfortable and healthier space.

I would think cork should float, but maybe that's not the most chemical free way to go. Stained concrete with some wool rugs might be.

If you have concerns about chemicals from elsewhere in the house, I'd look at the ventilation rate and also at maintaining a slight positive pressure. And test for radon (it's worse than most chemicals and technically, there is no safe level). 50% RH is a good level for humidity in the basement.

"moisture is coming from the ground"

Bob - in this case, is it not more likely that the moisture (dampness) is just humidity condensing on the cooler surface? The VCT along with the blackout would be as impervious as 10 mil poly.

OK. For staining concrete...

we would have to remove all the adhesives below the tile, and then below that there is the DISGUSTING black mastic from the old vinyl tile from the 60s that was down before. I dont' want to buy chemicals and just wash it off--I know those products exist because I looked into doing this before we did the VCT (I WISH we'd just done that at the time!!).

I've read that you can rent a concrete grinder, but I can't deal with that at this point (too many hazards and too laborious) and my H isn't handy. Would somoene do this for hire?

I guess this would be a much cheaper solution than new flooring,yes? Are stains extremely chemicall-y? Can you recommend some excellent ones? I love the way stained concrete looks, for sure.

"the moisture (dampness) is just humidity condensing on the cooler surface"
of course it is, so the solution is to reduce the humidity by cutting down on the moisture getting into the space. There is a perception that basements are inherently damp but that is false - they do not have to be that way.
Perhaps the thing to do would be to place the poly on top of the VCT. the poly will also help to keep out radon.

johr: wool rugs would absorb moisture & grow mold; wrong place for them!

Posted By Bob I on 18 Jul 2013 06:58 AM
"I'm not sure the dampness is coming from the concrete floor. "
I've been building houses for many years, and for a long time built houses with cool, humid basements, probably similar to yours. until I realized that the moisture is coming from the ground - through the porous concrete - and that we have the means to insulate and damp proof the space. Now the homes I build have dry basements which are much more comfortable, heat easier and keep the whole house at more comfortable levels of humidity.
It is harder to retrofit an existing house and without dealing with the walls so you'll still have some moisture coming into the basement through the concrete, but sealing the floor will cut down the moisture levels and give you a much more comfortable and healthier space.

In the eastern half of the US summertime humidity in basements will usually track the OUTDOOR AIR dew points- infiltration air leakage is as-big or larger factor than what's coming through the concrete in most (but not all houses.)  You have to treat both air leakage and ground moisture.

In the western half of the US most basements are NOT usually damp & humid, full of mold, even in cooler-wetter climates like the Pacific Northwest, again, an indication that the main moisture drivers is the ventilation/infiltration air.

Air sealing, then insulating the basement walls & slab goes a long way toward reducing mold-hazard in the muggy-east.  With insulated walls & floors the summertime temps in the basement rise a few degrees, but importantly, the surfaces stay well above the dew point.  Air sealing both the basement (foundation sills & band joists are usually a bigger leak than windows & doors), and the attic floor plane reduces the total "stack effect" draw, which otherwise tends to suck conditioned-space air into the attic, and humid outdoor air into the basement. Sealing both the top and bottom of the stack greatly reduces the unintended infiltration-ventilation, and in an air conditioned home the dew point of the basement air will then pretty much track that of the conditioned space rather than the outdoor air.

Got a zip code for where this house is located? (For climate & ground temp purposes, which can affect recommendations.)

If the floor isn't level, then a concrete overlay (with plastic under it and stain on it) might be of interest.

I have carpet in my basement and with standalone dehumidification (do not count on the A/C), I have zero problems with mold, smell or dampness. Wool, being naturally mold resistant, would be even better. And rugs are easily removable if there is ever a leak (I have had that from above).

Zip code is 48309. I won't be able to check back in until tonight or maybe tomorrow, but I'm needing to make a decision fairly soon and I really appreciate the help!

I don't want carpet, but rugs over something like stained concrete wouldn't bother me. You can remove/replace them much more cheaply than a whole roomful of carpet and you can take them places to get them cleaned if necessary.

Posted By purrus on 18 Jul 2013 12:57 PM
Zip code is 48309. I won't be able to check back in until tonight or maybe tomorrow, but I'm needing to make a decision fairly soon and I really appreciate the help!

I don't want carpet, but rugs over something like stained concrete wouldn't bother me. You can remove/replace them much more cheaply than a whole roomful of carpet and you can take them places to get them cleaned if necessary.

The ~47F deep subsoil temp in ZIP 48309 is low enough that any sort of rug would increase the likelihood of mold in the rug, since the slab would run even colder due to the insulating aspects of the rug.  The colder temperatures increase the relative humidity and condensation potential at the rug-underlayment.

A solution for that would be to put an inch of rigid EPS foam over the slab (2" is better) then half-inch plywood or OSB tongue and groove sheathing through-screwed to the subfloor 18" on center with TapCons, onto which any type of flooring can be applied. There is an energy use benefit to adding the foam as well, and at 2" (R8) EPS would still have a longer term payoff on energy savings alone. You are located in US climate zone 5- see the R-values in table-2 p10 of this document.

To insulate the foundation walls several approaches can be taken, all of which call for some amount of ridge foam insulation between the foundation and any interior finish wall (with, or without more insulation.) To hit the "whole wall" R value of R15 called out in that RR-1005 table without creating wintertime condensation or a moisture trap, 1.5" of EPS trapped to the foundation behind a non-structural 2x4 wall insulated with UNFACED R13 batts works.  The floor foam & OSB/ply subfloor should run right up to the wall-foam layer, with the studwall plate resting atop the sub-flooring. Running it 24" on center and with single stud plates is fine- it's not holding up the house, only the insulation & finish wall.  You can get away with as little as 1" of EPS as wall foam from a wintertime condensation point of view, but if you go much thinner than that you risk mold growth where the batts meet the EPS.

All of which is a much bigger project than simply a floor covering.  If the slab & wall insulation measures will have to wait, just paint the floor and air-seal the band joist/foundation sill as best you can when you can, and keep a dehumidifer going in the basement.  Don't even THINK about putting down a rug on painted uninsulated concrete- it'll almost certainly develop mold/mildew issue in just one season.

BTW: Many will suggest using XPS (pink/blue/green) rather than EPS for the rigid foam, but XPS will outgas most of it's HFC134a blowing for the next 50 years, which isn't a huge human-toxicity thing, but IS a very powerful greenhouse gas.  EPS is blown with pentane, and is 99% outgassed by the time it hits the distributor's lot.  Also, never use polyisocyanurate on or under slabs (but it would be OK for the walls, as long as the cut bottom edge rested on EPS, not concrete), since it can wick moisture, taking on water slowly over time, losing a good portion of it's R-value.

"humidity in basements will usually track the OUTDOOR AIR dew points"
this house has apparently had water issues since the previous owner installed a drain, so I'm assuming there is a higher than average moisture level in the ground below. I agree entirely with adding foam and plywood, or foam and concrete; the foam will definitely help with moisture issues. Foam with plywood will give you a warmer, drier and softer floor, and you can install some kind of floating laminate flooring over it, which should be ideal for a playroom.

For the plywood/osb - buy Advantech. treated to not absorb water; less chance of ever having issues should the space flood. Much better product than regular osb or ply.

Don't even THINK about putting down a rug on painted uninsulated concrete- it'll almost certainly develop mold/mildew issue in just one season.

Slab insulation will save energy and add a little comfort, but I checked the difference between painted, uninsulated concrete basement floor and under 3 different (and non moldy after many years) rugs. The average difference - an inconsequential 1 degree (deep ground is ~50F here). Set your dehumidifier for 50% and mold under rugs is a NON issue.