Plastic chair mats...warning

[fordman84]

Not really a DIY but something I learned about this weekend. To set the scene we have an office on the first floor of a concrete slab house where my wife works most days and it is carpeted. I hate carpet (sorry @Edisto_Tiger) and only three rooms in the house remain carpeted, but I digress. I got one of those nice thick plastic mats so she can roll around in her chair easier, that was about a year to 18 months ago. Fast forward to this weekend when I take that mat up because I need to move the desk to put up new curtains. I notice a discolored spot and the smell of mildew. Turns out that the vapor barrier that is part of carpet underlayment can go bad fairly easily and placing something large like the plastic mat allows for trace amounts of moisture that concrete wicks up to remain under there and mold. Disgusting, but I never thought to take the plastic mat up and I guess I'd need to do it weekly at most.

So we are getting new carpet in all three remaining rooms since she doesn't want hardwoods in the office, master, or kids room. I told them I want the longest warranty on the underlayment they have, so if this happens again they can pay for it

 

[Peter Gozintite]

Huh. Sounds like the vapor barrier under yhe concrete failed too.

 

[fordman84]

Huh. Sounds like the vapor barrier under yhe concrete failed too.

I'm not sure there is a vapor barrier under the concrete, maybe there is supposed to be one. I could apply a sealant, but let's face it I probably won't. I'll just let the people do their thing when they install it.

 

[Bayou Tiger]

I'm not sure there is a vapor barrier under the concrete, maybe there is supposed to be one. I could apply a sealant, but let's face it I probably won't. I'll just let the people do their thing when they install it.

There is supposed to be one.

If you didn't have a vapor barrier whenever it rained a lot you would have wet concrete under carpet.

You'd know real soon around these parts....

 

[ojb81]

Not really a DIY but something I learned about this weekend. To set the scene we have an office on the first floor of a concrete slab house where my wife works most days and it is carpeted. I hate carpet (sorry @Edisto_Tiger) and only three rooms in the house remain carpeted, but I digress. I got one of those nice thick plastic mats so she can roll around in her chair easier, that was about a year to 18 months ago. Fast forward to this weekend when I take that mat up because I need to move the desk to put up new curtains. I notice a discolored spot and the smell of mildew. Turns out that the vapor barrier that is part of carpet underlayment can go bad fairly easily and placing something large like the plastic mat allows for trace amounts of moisture that concrete wicks up to remain under there and mold. Disgusting, but I never thought to take the plastic mat up and I guess I'd need to do it weekly at most.

So we are getting new carpet in all three remaining rooms since she doesn't want hardwoods in the office, master, or kids room. I told them I want the longest warranty on the underlayment they have, so if this happens again they can pay for it

Huh?

 

[fordman84]

There is supposed to be one.

If you didn't have a vapor barrier whenever it rained a lot you would have wet concrete under carpet.

You'd know real soon around these parts....

THought that was the point of the vapor barrier on top of the concrete.

 

[Bayou Tiger]

THought that was the point of the vapor barrier on top of the concrete.

 

[Rex Racer]

THought that was the point of the vapor barrier on top of the concrete.

The vapor barrier on top of the concrete will help protect the flooring, but concrete is porous and will always wick moisture. If the builder put a poly vapor barrier before he poured the slab I seriously doubt it failed.

 

[Bayou Tiger]

The vapor barrier on top of the concrete will help protect the flooring, but concrete is porous and will always wick moisture. If the builder put a poly vapor barrier before he poured the slab I seriously doubt it failed.

Yeah it's usually 7 mils at the minimum...9 mil in some regions.

Pretty thick stuff....

 

[Rex Racer]

Yeah it's usually 7 mils at the minimum...9 mil in some regions.

Pretty thick stuff....

Yeah, I'm pretty sure that most good builders are using 10 mil around here.

 

[fordman84]

The vapor barrier on top of the concrete will help protect the flooring, but concrete is porous and will always wick moisture. If the builder put a poly vapor barrier before he poured the slab I seriously doubt it failed.

North Texas is a bitch on foundations. We have so much soil movement each year that every house has foundations moving around. I seriously doubt any poly barrier is still working after 20 years.


With that said, I have a plumber doing a slab leak test at this moment. Fingers crossed.

 

[Rex Racer]

North Texas is a bitch on foundations. We have so much soil movement each year that every house has foundations moving around. I seriously doubt any poly barrier is still working after 20 years.


With that said, I have a plumber doing a slab leak test at this moment. Fingers crossed.

I hope that went well for you. I have very little knowledge of building on a slabs other than stand alone garages and few detached condo associations that were built in swamp land in Merrimack, NH.

 

[fordman84]

I hope that went well for you. I have very little knowledge of building on a slabs other than stand alone garages and few detached condo associations that were built in swamp land in Merrimack, NH.

No slab leak. I had done my own meter flow check and it moved a tiny bit, but I think it was the icemaker I forgot to turn off before we left. Plumber found nothing.

 

[huskers1217]

I just put luxury vinyl in the master bedroom

 

[fordman84]

I just put luxury vinyl in the master bedroom

We aren't talking about bed sheets here, sir.

 

[Rex Racer]

No slab leak. I had done my own meter flow check and it moved a tiny bit, but I think it was the icemaker I forgot to turn off before we left. Plumber found nothing.

If you put a 6 mil or thicker plastic vapor barrier down before you put the pad down for whatever laminate flooring you are using I would think you'll be OK going forward. I would use the plastic vapor barrier even if whatever pad you are using claims that it is also a vapor barrier.

 

[fordman84]

If you put a 6 mil or thicker plastic vapor barrier down before you put the pad down for whatever laminate flooring you are using I would think you'll be OK going forward. I would use the plastic vapor barrier even if whatever pad you are using claims that it is also a vapor barrier.

When I've installed our laminate floorings I have used good vapor barrier and tape. This time we are going with carpet. So I ordered the highest grade, dual barrier frothed urethane padding. Should prevent anything coming up through and divert it off to the sides. I will ask about putting another barrier or sealing the slab before doing that.

After talking with the plumber he was thinking it might be a moisture issue with our weep holes, since that room is basically in a corner. I'm going to cap the sprinkler head that is in that corner against two exterior walls and then redo the ones that are on the yard side of the flower beds to point in and spray down. See if that doesn't help.

 

[Peter Gozintite]

When I've installed our laminate floorings I have used good vapor barrier and tape. This time we are going with carpet. So I ordered the highest grade, dual barrier frothed urethane padding. Should prevent anything coming up through and divert it off to the sides. I will ask about putting another barrier or sealing the slab before doing that.

After talking with the plumber he was thinking it might be a moisture issue with our weep holes, since that room is basically in a corner. I'm going to cap the sprinkler head that is in that corner against two exterior walls and then redo the ones that are on the yard side of the flower beds to point in and spray down. See if that doesn't help.

Irrigation causes more problems than people realize.