Moisture through slab

[Jim Luttrall]

I'm looking for ideas concerning discovery of moisture issues as well as dealing with moisture issues through a slab on grade. I have has a couple of phone discussions and will be heading out to the property tomorrow for a first hand look. Here is the scenario so far. The client bought the house about 2 years ago with a new/newer wood floor in place on a 1992 house. Monlothic slab on grade single story. The wood floors cupped or warped badly and have been mostly removed. The client is now living with exposed concrete. He has done the following: had insurance adjusters involved but no help or answers from them, said to call them when he figures out the problem. Had the roof replaced with photos during tear-off trying to find any leak with no leaks found. Had two separate plumbers do testing of the water and drain lines, no leaks. Had a structural engineer look at the slab, no help. He did mention doing core samples of the concrete. (my thought is core samples to find vapor barrier is going to be ineffective and costly). Has done a plastic sheet test with positive results in random locations. I told him I probably won't be able to give much help but I will take a look. Any help the brain trust here at IN can give will be appreciated. My hypothesis is there is no functioning vapor barrier under the concrete. Question: is there a paint or treatment for stopping moisture flow that can be placed under wood floors other than plastic sheet vapor barrier under floating wood floors? Question will IR scan of the floor be of any use? Thanks, Jim

[Billy Stephens]

Question: is there a paint or treatment for stopping moisture flow that can be placed under wood floors other than plastic sheet vapor barrier under floating wood floors?
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[Jerry McCarthy]

Jim

A concrete slab without being equipped with a properly installed moisture barrier beneath it and not torn up by the concrete crew when pouring the slab,will always have moisture issues. Joe Lstburek once described concrete slab foundations as giant tampons that attracted moisture like magnets. His description, not mine.

[Ted Menelly]

I'm looking for ideas concerning discovery of moisture issues as well as dealing with moisture issues through a slab on grade. I have has a couple of phone discussions and will be heading out to the property tomorrow for a first hand look. Here is the scenario so far. The client bought the house about 2 years ago with a new/newer wood floor in place on a 1992 house. Monlothic slab on grade single story. The wood floors cupped or warped badly and have been mostly removed. The client is now living with exposed concrete. He has done the following: had insurance adjusters involved but no help or answers from them, said to call them when he figures out the problem. Had the roof replaced with photos during tear-off trying to find any leak with no leaks found. Had two separate plumbers do testing of the water and drain lines, no leaks. Had a structural engineer look at the slab, no help. He did mention doing core samples of the concrete. (my thought is core samples to find vapor barrier is going to be ineffective and costly). Has done a plastic sheet test with positive results in random locations. I told him I probably won't be able to give much help but I will take a look. Any help the brain trust here at IN can give will be appreciated. My hypothesis is there is no functioning vapor barrier under the concrete. Question: is there a paint or treatment for stopping moisture flow that can be placed under wood floors other than plastic sheet vapor barrier under floating wood floors? Question will IR scan of the floor be of any use? Thanks, Jim


An acrylic or epoxy garage floor sealer will work for a very good period of time. The only concern is that it will eventually separate if there is that much moisture under the slab. Probably not for a long period of time.

A French drain dug down to below the bottom of the grade beam with a sump pit to collect water and move it away from the foundation. Just below the depth of the grade beam should pull the water from under the slab as well. My question would be the overall grading and drainage around the home. The property may slope from one side of the rear or front to the home. If that is the case the drainage on that side or end of the property would be the area to attack.

Bad news if there is no barrier under the slab.

Either that or suggest tile throughout the home with throw rugs. Moisture would not be a problem with the tile.

[Jerry Peck]

He did mention doing core samples of the concrete. (my thought is core samples to find vapor barrier is going to be ineffective and costly).

I had that done on a new house about 15 years ago and proved that the plastic sheeting had been caught in the rake being used to pull the WWM up from the bottom and pulled the plastic sheeting back from the lap. A 16" core was drilled into and through the slab, you could reach your hand into the hole and poke your fingers back in between the sand fill and the slab, and ... just barely feel where the plastic sheeting was - on both side of the hole, meaning there was about a 20" opening in the plastic sheeting.

That wood floor was so wet you could press your thumb down onto the wood and squeeze water out of the wood. :eek:


Has done a plastic sheet test with positive results in random locations.

Not good. Possibly no plastic sheeting or very, very poorly installed plastic sheeting with many open laps, not sealed around penetrations, etc.


My hypothesis is there is no functioning vapor barrier under the concrete.

"there is not functioning vapor barrier" ... with emphasis on "no functioning" - I believe you are correct.


Question: is there a paint or treatment for stopping moisture flow that can be placed under wood floors other than plastic sheet vapor barrier under floating wood floors?

There really is only ONE choice ... and not what Billy posted ;) ... and that is "whatever the manufacturer of the wood floor specifies" be done.

ANYTHING ELSE and there will be absolutely NO warranty on that wood floor and replacing that wood floor may well be a frequent occurrence.

My best guess as to the the wood floor manufacturers will specify is ... no wood floor be installed.

Typically (almost always) 6 mil plastic sheeting is used for the moisture barrier under the slab, some wood floor manufacturers *specify* a minimum of 10 mil moisture barrier - which means they can basically walk away from any problems as no builder installs the 10 mil plastic sheeting.


Question will IR scan of the floor be of any use?

If the bare concrete is exposed, probably will help.

[Ron Bibler]

Jim

A concrete slab without being equipped with a properly installed moisture barrier beneath it and not torn up by the concrete crew when pouring the slab,will always have moisture issues. Joe Lstburek once described concrete slab foundations as giant tampons that attracted moisture like magnets. His description, not mine.

I had a new home a few weeks back with water stains on an interior wall.
Look like the same thing.

Santa Rosa California Home Inspection - Exterminating & Thermal Imaging (http://www.healdsburgpestcontrol.com)

Best

Ron

[Rick Hurst]

Jim,

There is some homes over in Rowlett that have this same issue. Seems the homes were built over where some ponds used to be. Evidently the groundwater is now rising up and coming through the slabs.
Vapor barriers have all kinds of gaps and tears in them. I used to watch them put it down after I did termite treatments. I could see how it would be easy for moisture to bleed through the poly.

I'd still bet in your deal, there is a plumbing leak somewhere. Ever watch how these plumbers do a pressure test around here. Its a joke.

rick

[Jim Luttrall]

Rick, this is around GB and Firewheel in Garland. I looked at the terrain map from Google but did not get much of an idea of what it looked like as far as creeks, etc. That whole area seems low to me when I drive through. He did say that the garage had dropped and SE was recommending foundation repair (piers). I told him that if it was a vapor barrier problem that there was no real fix, just put down ceramic tile and forget the wood floors. I'm not a big fan of wood glued down to concrete anyway. Anybody have any experience with the floating wood floor systems in such situations? Seems like the engineered floors over it's own vapor barrier/pad might work. What is the deal with my postings? I put in spaces between every sentence but it goes away when posted. None difference when editing and no emoticons (smiles). The box is not checked to disable smiles in text and I have tried the basic and advanced editor WYSIWYG, fluid. Seems to be just this site when posting but reading is OK. ???

[Billy Stephens]

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There really is only ONE choice ... and not what Billy posted ;) ....
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[Ron Bibler]

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Say Bill has that dog ever got that ball off his nose?:D

Best

Ron
Santa Rosa California Home Inspection - Exterminating & Thermal Imaging (http://www.sebastopolpestcontrol.com)

[Bruce King]

There is a problem near here on a 11 month old home where the development had an irrigation head that was left active underneath a slab house. Wet mud came up through the slab penetrations into base cabinets.

[Jim Luttrall]

Here is a very helpful article on the subject BSI-003: Concrete Floor Problems — (http://www.buildingscience.com/documents/insights/bsi-003-concrete-floor-problems/?searchterm=wood%20floor%20slab)

[Phil Brody]

There is a product that can be applied directly to the concrete that forms a rubber like elastomeric sealer. Then apply 1/2" osb with polyurethane adhesive (pl2000) place 30 lb roof felt over that and nail down either solid wood or engineered wood floor to that. Before applying any wood product polyurethane the backside to prevent any residual absoption of moisture. Always leave proper spacing for movement. Worked for me on more than 1 occasion.

[Phil Brody]

Also there are some good looking wood ceramics that will not give a problem. Some are so good you have to tap on them to tell they are not wood !

[John Kistner]

The moisture in the slab is caused by the failure to install a moisture barrier below the concrete. This cannot be stopped without removal of the slab and re-installation. You can go to a ceramic tile supplier and purchase a product that goes directley on the top of the concrete to stop moisture, it is re and I do not remember the name (I used it on my sisters house with the same problem and it cured the problem). However the best way is to replace the slab however it can be expensive the other product will keep the moisture out of the living area and as long as heat and air conditioning is applied it will work.
John Kistner
Harold D. Kistner Construction Co., Inc

[Ken Garrett]

There is a very good product that we used on some homes in California that had moisture coming up through the slab. The company is Moxie. They have some good information that you may find valuable on their website, Moxie International - Concrete Admixture, Sealers and Water Intrusion Solutions for Concrete & Masonry (http://www.moxie-intl.com). Works very well to prevent water vapor or liquid water from penetrating the slab surface. A 6-mil vapor retarder is not enough to prevent water vapor from entering a slab surface and almost always are penetrated during installation. Vapor Barriers should meet ASTM E-1745 standards and be resistant to holes and tears. More and more builders in those states where litigation has made a big impact with homebuilders are using at least a 10-mil vapor retarder and many have go to the expense of using some of the 20-mil or greater materials under the slabs. Also, without a capillary break, i.e. an aggregate layer under the slab, liquid water may be forced up through the slab, especially with the cracks we get due to our expansive clay soils (many locations). In Texas it is almost standard practice to place concrete on 6-mil poly with numerous holes/tears and without sealing around penetrations. It is really suprising there are not more water related issues. Also, I would make sure the grade around the home has a good slope. As most know, it is also common practice to backfill around the home with sandy soils (easier to move that the native clays) which may allow water to enter below the slab, even with a good visible surface grade. Along with the uncompacted plumbing trenches that are perfect conduits.

[Deck Expert]

There are several test kits available for moisture testing a concrete slab; calcium chloride kits run around $25.00 each. Test runs from 60-72 hours, with the weight of the calcium chloride measured before the test and then again after it ends. The weight of water the kit has absorbed is taken and a formula is used to calcluate the total MVT.

MVT (Moisture Vapor Transimission) can be mitigated. As a waterproofer, I only use AQUAFIN or Dex-O-Tex products, they can reduce MVT from 5-25 #'s down to 1-3% when installed properly.

Most flooring products can withstand up to 3-5#'s of moisture pressure coming up through a slab. Wood floors absorb the moisture and cup and curl. Epoxy coatings/lineoleum etc. just delaminate from the floor. Carpet will eventually sprout mushrooms and other interesting plant life before rotting away.

Aquafin-www.aquafin.net

Dex-O-Tex- Crossfield Products Crossfield Products Corp - Construction Coating, Overlay and Fluid Applied Flooring Materials (http://www.crossfieldproducts.com)

The installation ain't cheap and only authorized applicators can put these products down...the over the counter crap gives me the heebie jeebies.

Bill Leys
The Deck Expert
DeckExpert.com (http://www.deckexpert.com)

[Ken Garrett]

Jim,

There was a situation not far from the area your talking about that had water causing a foundation failure. The thing is, the water source was from a house about a block away where the owners had built the
Garden of Eden and was watering like crazy to keep everything alive. The water was being channeled between the clay and rock ending up at this house. Not really a perched water table, but more of an underground stream. There was a little topo to allow the water to be transferred downward, but not much.

Also, I would strongly avoid any of the inexpensive over-the-counter floor sealers. Mosts have no or limited warranties and not really intended for a large scale project. A floating floor would still need to have the concrete sealed to prevent moisture problems/mold issues.

Ken Garrett
Quest Real Estate Support Services
TREC #2867

[Glenn Duxbury]

Hi, All &

What about one of 'those' proprietary plastic "waffle"-type membranes Mike Holmes touts, to 'always use beneath a wooden floor on concrete' - without exception (sorry name escapes me) ?


CHEERS &

Have a GREAT weekend !

[Ken Garrett]

Glen, you may have something there. I have not seen DITRA used for wood floors, but I can't see why it couldn't be used. It certainly provides a good waterproofing for tile applications. Except for being a little costly, and figuring out if you could fill the "waffle" areas with a grout before placing a glue-down wood floor on top of it...or exactly how to use a floating floor over this material. The manufacture would also need to agree to warrant the material for this use...presuming someone is going to stand behind this installation...

Ken Garrett
Quest Real Estate Support Services

[Stacey Van Houtan]

A radon mitigation type of system would reverese some the moisure pressure if capalliry break exist.

[Dana Bostick]

As for using Infrared, it will only tell you that you have moisture. That, you already know. Not the right "tool" for this application although it might home in on the area of the problem.

[Ken Garrett]

Stacey, in Texas we use mostly post-tensioned slabs with a "cushion sand" beneath the slab. The sandy material has a lot of clay and does not provide the properties needed for radon mitigation. There is really no "flow-thru" for gases with these foundations. Unlike some areas of the U.S. radon is not an issue here so no thought is put into a 4" layer or sand or gravel for gases...or water vapor to escape. Also, since the vapor retarder used under the slabs are not properly sealed, moisture could still enter through the slab.

[Jim Luttrall]

Just got back from the inspection on this house.
All signs point to inadequate vapor barrier and improper floor installation.
No grading issues worth mentioning, no water leakage up through the slab, just vapor which is collecting on the back of the test plastic.

[Jim Luttrall]

My advice was to choose a less water sensitive flooring material or to put down a vapor barrier, and a nail down product.
Thanks Guys.

[Stacey Van Houtan]

Sand would allow the flow of air and negative pressure under the slab would occur. This would be my last choice and if grade beams exist than it may be to complcated. Surface treatmets would work if the pressure is not too much which is almost all the time in my area. Moistueblok or other pvc type products work well

[Ken Garrett]

Stacey, I would go and check out the Moxie International website. I have been extremely impressed with their product and what it can do to concrete. Different than other products because it actually interacts and eliminates most of the voids and capillaries that allow gases to go through the concrete. I fixes not only water vapor issues, but also other gases. I has been several years ago since I talked to anyone with this company, but the last time I did they were using one of their products in all of the concrete mixes for the WalGreen Stores. It allowed them to poor a low water ratio concrete while producing a water resistant concrete surface. Also, there products do not form a membrane, so you can still use glue down floor coverings. I know...sounds too good to be true...I thought so too until we used the product.

Sounds like the inspection of the home was about what was expected. Not a lot of options...maybe staining the concrete and sealing it...that is very popular now...

Ken Garrett
Quest Real Estate Support Services

[John Kogel]

My advice was to choose a less water sensitive flooring material or to put down a vapor barrier, and a nail down product.
Thanks Guys.There is an OSB subflooring that has a plastic underlay attached to it. The plastic is dimpled to raise the wood off the concrete. Too bad it's not plywood.

What might work is that orange dimpled plastic applied with thinset and then a plywood subfloor. I'd drive in stainless screws before the thinset sets up. (I just made this up and advise no one to try it. :>)

I'd cover the wood subfloor with vinyl flooring and area rugs, tell the wife we can try the engineered hardwood in a couple of years. :)

[mark tyson]

I'm looking for ideas concerning discovery of moisture issues as well as dealing with moisture issues through a slab on grade. I have has a couple of phone discussions and will be heading out to the property tomorrow for a first hand look. Here is the scenario so far. The client bought the house about 2 years ago with a new/newer wood floor in place on a 1992 house. Monlothic slab on grade single story. The wood floors cupped or warped badly and have been mostly removed. The client is now living with exposed concrete. He has done the following: had insurance adjusters involved but no help or answers from them, said to call them when he figures out the problem. Had the roof replaced with photos during tear-off trying to find any leak with no leaks found. Had two separate plumbers do testing of the water and drain lines, no leaks. Had a structural engineer look at the slab, no help. He did mention doing core samples of the concrete. (my thought is core samples to find vapor barrier is going to be ineffective and costly). Has done a plastic sheet test with positive results in random locations. I told him I probably won't be able to give much help but I will take a look. Any help the brain trust here at IN can give will be appreciated. My hypothesis is there is no functioning vapor barrier under the concrete. Question: is there a paint or treatment for stopping moisture flow that can be placed under wood floors other than plastic sheet vapor barrier under floating wood floors? Question will IR scan of the floor be of any use? Thanks, Jim

What would be the clients reasoning be for doing a core sample? So what if he discovers that the vapor barrier is either inadequete or not there daaa, what does he do then? Tear the house down and start again? Is it possible the wood floor was not installed properly the first time? Is there evidence of moisture wicking on the baseboards, door casings, or cabinetery? if the ansewere to above is no then do moisture testing.On the concrete use only the tried and true method that is reconized by all of the wood flooring mfgs. as the most accurate (calcium cloride). If that test proves abnormaly high moisture then look at the exterior grading, which is the problem 95% of the time. does the grade slope away from the structure 5% in the first 10' and then 2% there after until it meets the point of discharge. if your client who apparently is in wood floor hell has done his due diligance he would have been able to google this information. My gut feeling is that he is looking for a pardner in litigation. Tread cautiously my friend

[Jim Luttrall]

What would be the clients reasoning be for doing a core sample? So what if he discovers that the vapor barrier is either inadequete or not there daaa, what does he do then? Tear the house down and start again? Is it possible the wood floor was not installed properly the first time? Is there evidence of moisture wicking on the baseboards, door casings, or cabinetery? if the ansewere to above is no then do moisture testing.On the concrete use only the tried and true method that is reconized by all of the wood flooring mfgs. as the most accurate (calcium cloride). If that test proves abnormaly high moisture then look at the exterior grading, which is the problem 95% of the time. does the grade slope away from the structure 5% in the first 10' and then 2% there after until it meets the point of discharge. if your client who apparently is in wood floor hell has done his due diligance he would have been able to google this information. My gut feeling is that he is looking for a pardner in litigation. Tread cautiously my friend
The core sample idea was from the structural engineer, not the client.
As I told the client, he had the order backwards from my traditional real estate transaction inspections. He already had the specialist involved going from specific to general inspection rather than general to specialist. Having the results from all the other tests was very helpful for me though.
I basically told him what he did not want to hear, that his flooring installation was the problem.

[mark tyson]

I'm looking for ideas concerning discovery of moisture issues as well as dealing with moisture issues through a slab on grade. I have has a couple of phone discussions and will be heading out to the property tomorrow for a first hand look. Here is the scenario so far. The client bought the house about 2 years ago with a new/newer wood floor in place on a 1992 house. Monlothic slab on grade single story. The wood floors cupped or warped badly and have been mostly removed. The client is now living with exposed concrete. He has done the following: had insurance adjusters involved but no help or answers from them, said to call them when he figures out the problem. Had the roof replaced with photos during tear-off trying to find any leak with no leaks found. Had two separate plumbers do testing of the water and drain lines, no leaks. Had a structural engineer look at the slab, no help. He did mention doing core samples of the concrete. (my thought is core samples to find vapor barrier is going to be ineffective and costly). Has done a plastic sheet test with positive results in random locations. I told him I probably won't be able to give much help but I will take a look. Any help the brain trust here at IN can give will be appreciated. My hypothesis is there is no functioning vapor barrier under the concrete. Question: is there a paint or treatment for stopping moisture flow that can be placed under wood floors other than plastic sheet vapor barrier under floating wood floors? Question will IR scan of the floor be of any use? Thanks, Jim


The core sample idea was from the structural engineer, not the client.
As I told the client, he had the order backwards from my traditional real estate transaction inspections. He already had the specialist involved going from specific to general inspection rather than general to specialist. Having the results from all the other tests was very helpful for me though.
I basically told him what he did not want to hear, that his flooring installation was the problem.

You done good? i'm new to this site so I don't know how to insert those smiles and things

[Daniel Leung]

...He already had the specialist involved going from specific to general inspection rather than general to specialist. Having the results from all the other tests was very helpful for me though.
....
Jim, if he had called a swimming pool repair contractor, he does not need a HI anymore.:)

[Joseph Farsetta]

The best thing to do is to identify the problem prior to recommending a solution. Absent of this, products such as Dry-Lock or ThoroSeal may be helpful. I used Thoroseal on a family member's home with hydrostatic issues in a slab-on-grade scenario over 15 years ago, and haven't had a problem since.

Again, investigation is the BEST course of action, but the ThoroSeal is also a pretty cheap date.

[Stacey Van Houtan]

HI's dont sell your self short. I follow so called specialist a lot. Just as during constriction a General contractor hold together the various trades a HI can give a overall persective and see things that those with professional blinders on many times miss. This i find many times when doing expert witness work.