Wet plywood subfloor

Wow, that really, really sucks. Well, the obvious problem is that you have a water issue and it is a new one because sub flooring, even with the smallest leaks, doesn't take long too get soak through and get weak, possibly warp and then start growing mold. You have to find the source, since the house is on a slab it could be a leaking faucet supply slowly soaking through room by room, it is doubtful that you have a foundation crack, but a crack in your slab is IMHO your most likely suspect. My suggestion would be to try and find the crack, grind into it and seal it as best as you can then find a closet and cut a hole in your slab for a sump pump (unless you already have one) to pump out some of the water from under the slab. As far as your kitchen goes, tear out as much as you can and repair the problem, whatever it may be, then lay new sub flooring and put your kitchen back together. good luck!

You mention drought last summer, but not the conditions now in the marshy area. The capacity of soil to absorb water can be altered severely if the natural flora are killed off by drought. Very dry conditions might also cause underground drains (such as french drains serving your house or the area) to collapse at some point underground, and to block the usual route that draws water away from your home.

Since pipes in the slab are difficult to assess without tearing up the house, I would first of all do a little digging outside around the foundations, and see if the ground is wet enough to indicate an outside source seeping in, which might be dealt with by renewing the outdoor drainage system.

Is the land on a slope? Does the ground rise above the slab level, outside, at some places around the house. It could be seepage coming through the walls. I have had this problem & the water used to seep up between the tiles (actually about 3 ft out from the wall), the floor in between seemed OK, but you could dry the grout between the tiles & then watch as more water came up. Once I dug the earth away from the outside walls the seepage stopped.

Thw water was seeping through the masonry walls & seeping along the top of the slab , but underneath the tiles.

This may not be your case, but its another possibility of how you can get water under the floor coverings.

Sounds to me like you have a leaking pipe in the slab! do the pipes go through the slab? I have heard of this happening before only way to fix it was to disconnect the pipe and run it round the outside

Cheers for now

peugeot man

A leaking pipe is the probable source of this water problem. If the water supply pipes are embedded in the slab, a failure after thirty years isn't surprising. The leak is most likely in the hot water supply, caused (or aggravated) by the pipe's expansion and contraction. If the pipes are galvanized steel, thinning of the pipe wall from corrosion is also likely.

If the water pipes are not embedded, but run under the slab, you might be able to repair the leak if you can find it. A local plumber who has dealt with this problem on other occasions might propose a reasonable solution. Running copper tubing through the attic is one possibility.

Repair of the floor is another matter. A plywood subfloor laid over a slab is usually supported by cleats so as to leave a space, which is now full of water. Good luck.

All of the responses and tips will be seriously considered. This problem won't go away by itself. We are not on a slope, and there is nothing unusual about the water table. I understand there are some pipes in the concrete slab. French drain might be the problem since something must have happened during the dry spell in 2009. Appreciate the quick and topical responses.

As stated earlier there are a lot of possible problems here. I would see if there is an easy way to pressure test the piping before I started chipping or digging anything out. If it does leak you can often find the leak with a little additional pressure and or a set of listening ears to amplify the sound of the leak. There are ways to chip out the pipe and repair it without incurring too much cost.

Good luck

I forgot to mention in my previous response about pressure testing, as a guest ( forgot to log in )that the drought may have allowed to slab to crack. That could explain the pipes cracking. You might see if the floor can be dried out and saved if the leak can be repaired. If you do end up teaing it all out I would strongly advise using a different system such as floating the floor to level it or using a masonry based sort of underlayment so this sort of situation cannot happen again. Hopefully no more settlement will occur but you never know.

Hello,

Water leaks are tough. Unless you're in far southeast TX you've had some low temperatures so far this winter and though one wouldn't expect a pipe in the foundation to freeze a pipe in the ceiling or attic space could. Water finds its way, if an overhead pipe were leaking the water could be running down inside a wall and spreading across the slab.

We suffered from soggy carpet caused by a frozen outdoor faucet. There was no leaking when the sillcock was closed but whenever we watered, outside water leaked from a crack in the sillcock tube, somewhere between the recessed valve seat and the actual water outlet, and got to our carpet padding under the drywall.

"Sourdough" suggestion of pressure testing your piping is a good one. A leaking pipe is the most likely explanation if this problem is only recent.

Of course, ground water could have been seeping in under the slab for ages and only now built up enough to cause a noticeable problem.

If a leaking pipe is not the problem you need to drain around the house, which will also bleed sub-slab water away.

This should prevent ground water penetration, unless a spring has opened up under your house, and even then it will minimize it's effect.

When you replace the sub-floor, use compressed fiber-cement sheeting and coat with waterproofing (there is a good acrylic based one used for bathrooms). This will prevent water coming up from below and can sit in water virtually forever without damage (unless the water is excessively acid and even then it is quite resistant as the autoclaving done on the sheet reacts all free lime removing the main source of acid attack).

Whatever, rectification is going to be messy and probably expensive.

Good luck

Once you have confirmed that a pipe is leaking it may be located by lightly pressurizing the pipe with helium and then locate the leak with a helium detector. This method is very effective in locating leaks under concrete as the helium passes right through directly above the leak. There should be a local contractor available to offer this service.

If its a hot water leak you can walk around the floor in your bare feet. When you find a warm spot it should pinpoint the area. Then use a concrete saw cut out the area and repair.

I would run new piping above ground.

I would also check drainage around the house and make sure its repaired.

That's a nasty problem. I agree it likely is a line in the slab that is leaking and the moisture is moving thru the concrete. One crude way to check for supply leaks is to turn off all water to the house and check your water meter. Most water meters have a flow indicator even for very small flows. On meters in my area it is a little red triangle behind a sight glass on the meter. It spins if there is any flow.

I will throw out another scenario. If the ground beneath the slab stays wet, the slab may be wicking water up to the sub-floor. Conditions may have changed that allow this to happen such as higher moisture levels in the soil, plugged foundation drains or degradation of moisture barrier that would be below the slab.

Something that may fix this problem is to put new perimeter drains around the house. If the land is too wet and flat to drain you would need to feed the drains to an exterior sump hole with a pump. If much water is coming up (as opposed to in from the perimeter) to the foundation a sump hole may be needed in the slab that relieves the water pressure under the slab. This sump hole and pump would be placed in a closet like structure inside the house.

I too had the same problem. Living in southeast Texas and on a bayou, twenty years in a forty year old house. Ceramic tile but no plywood between tile and slab (not sure why they did that). No problems for fifteen years. Soil is very sandy were I live, after a few drought cycles the foundation settled somewhat. I developed a hair line crack that was evident on the tiles. With no plywood between slab and tile the crack in the slab transfered to the tile. Maybe that is why they put down plywood. After heavy rains, which can be quite frequent in SE Texas, water would wick up through the crack to the surface of the tile. In your case i guess it would wick in to the plywood then spread out. I solved my problem by installing rain gutters and directing that run off well away from slab. I also dug a shallow trench around the slab and buried a perforated sewer pipe covered in pea gravel and directed that to a lower part of my property. It's been over five years with no more problems. It was easy to determine where my water was coming from as it showed itself only after a hard rain. As you have a sponge between tile and slab it may be harder to determine if that is your problem.

Good luck

Ddifferent

Problems often occur in concrete due to a lack of a vapor barrier in the concrete. Concrete is permeable and can let water vapor permate through. Water vapor could be emitting from the water table so what you are experiencing could be vapor not water. If the floor finishes are recent it could be that the vapor was always there and as the plywood and floor went down the vapor was trapped and tooked time to accumulate and become evdient. The problem is just as bad where I live in the south-west since the dry exterior climate over a damp substrate creates a pressure difference that draws the water vapors up through capillary action in the concrete. If you had leaks it would probably only show in one area and test digging holes around the perimeter could show wet earth. Turn off all your water fixtures and check the meter to see if there is a leak. If the dampness is universal then that could point to condensation forming from rising vapors. Check out Stego Industries. I went to a lecture by them that was very helpful. You need to be careful about the ensuing mold also and impact that could have on your health. Hope this helps. Architect

I lived in Houston for twenty years and the soil is shrink and swell - this is a fact of life many places that don't require a decent foundation. Cracked slabs are a fact of life in those kinds of soils.

That is why most houses don't have basements.

You can get your property taxes reeducated by showing evidence of cracking. you can get a contractor to use a pump and correct some of the problem (or make it worse).

You will need the sub-floor replaced in any case and you need to check the sil plate to make sure it is not rotten as well.

Other than the taxes there is not an upside.

Best of luck!

Cosby

you have a problem.

We have had a very similar problem over here in Essex, UK and after a year of battling we are just about getting back to Normal.

I first discovered that we had a problem when a water mark started to grow up a wall in a Utility Room. We then remembered that we had seen a very similar problem when the house was new, some 20 years ago. At the time the problem was quickly determined to be a central heating pipe which had sprung a leak. Plumbers came in and fixed it!! Bulder supplied new carpets, Floor covering, and repainted the walls. This then happened again two or three more times before we had a solution that we thought that we could live with.

Forward 20 years and we knew what and where the problem was; this time the leak had been much slower and by the time we had workmen in, almost all of the ground floor of the house was saturated apart from two rooms.

I engaged a civil engineer to understand what was happening - I did not understand the house foundation construction. I now know - in Spades!

I am insured through my power supplier who sent a man out - he arrived with a set of screwdrivers despite being told that we were into concrete floors. He did not get very far until he arrived to ask me where my basement access was. With the house being built on estuary land there could be no basement but he had managed - with my chisels to cut his way around the pipes to the subfloor and a great hole underneath! At least there was no significant water there!

The major buildings insureres were then called in and they fixed the whole thing, every room and all relevant plumbing - the house was dried out, floors, walls and ceiling with driers and fans running night and day for three months before work could really start. A professional drying company who would not let the Insurance Company builders to start work before they had got the house dry.

After that the builders took over and within a few more months we were back in our home.!

Lesons learned

1 Understand your foundations and drainage.

2 Remove the source of water, whether external or internal.

3 Employ appropriate experts to advise.

4 Once problems are identified - remove wet materials - floors are very important here.

5 Get some drying actions going- it took us months to get the ground floor dry.!! With a mixture of fan blowers and professional dryers where moisture was extracted and water emptied from machines every day - also the walls and floors were measured every week - or thereabouts.

6 In the meantime you can at least start to plan your rework, - are you insured for this type of problem? - if not sort out how you are going to plan and do the work. It sounds like a large job, we , generally have smaller homes than you - being on a small island - I wish you luck.

7 Your first priority is to ascertain the source of the water that is saturating your floors and identfying a solution. In our case where the plumbing had failed for the fourth time I managed to convince the plumber doing the work that it would be best for the Insurance Company and everybody if we re routed some pipes, made them out of heavier materials and laid them out professionally with proper bends, connectors etc. and with thick tape covering all of the plumbing that had to be reburied in the concrete screed.

He agreed and I do not think that I have to worry on that score. Yes I checked evrything that he did as the three previous plumbers had all screwed up badly. If it happens again I will get some more professional advice before the next repair!!

8 I your case it could be either internal water from internal plumbing or external water from your surrounding land. That has to be the first identification that has to be made, then you should know what has to be done.

I wish you all the very best and would appreciate being kept in touch with your problem and solution.

Good Luck

Sleepy

Why in the world would plywood be installed between slab and tile? Asking for a good case of mold infestation, if you ask me.

First, make sure you are slab on grade construction, if not, not as expensive a repair.

In my experience, 30 years as a general contactor, if wood is placed over a slab, the concrete is ALWAYS waterproofed, and overlaid with a water barrier, which is sealed. Then normal construction can take place. This is done only where responsible building habits exist. If it is a tract home, you don't have this water barrier in place.

Definitely seems as though you have a plumbing leak, or ground water coming through cracks in the slab.If your supply lines are in the slab, then expensive is not a good descritive term, more like bankrupting. Consider re-installing supply lines in a place not prone to shearing action, such as concrete slabs can do.

New generation PEX tubing is a good product, not as expensive as copper, and easy to work with.

If it is ground water,rip all the flooring out and use a cement backer board to replace the plywood, then re-install the tile.

I recommend drying the concrete and sealing as I described.

On the other hand, if you like tile that feels like carpet, then you are good to go, except for the liklihood of a mold problem growing under your feet. Of course, fuzzy grout could look like carpet.....

A thought that came to mind... Is it "inside" water or "outside" water? IF you pay for your water, you would get periodic bills from the water company hopefully showing water usage. If your water usage has gone up in recent months, this would lead me to suspect pipes. If it has NOT gone up, then I might suspect an outside source. Compare your bills for last month with bills from a year ago (and two and 3 years ago). Of course if you are on a well, this whole idea is out to lunch... or if you did anything to change your water consumption over the last year or so. This may not help, but it is an idea.

Bill