Water and probably mold problem on slab floor

[TDKPE]

Tom; What is the heat source? The boiler could be leaking a little and evaporating as the heat and pressure increase. Leaks in the loops are bad! If the boiler is in good shape baseboard heat is an option, as well as an air handler in the attic. Hydronic air handlers are more common with the "A" coil too, so you could take advantage of energy savings down to about 40 degrees with a heat pump and have central air as a bonus 

 If you have standing water next to the concrete slab it will wick enough water to cause that amount of mold. Even if it's only seasonal, the spores will multiply every time they get moisture. My initial thoughts are that the grade has changed over time with the addition of mulch and growing trees (roots). The walls should be inspected for mold too. Pull some baseboards and cut out some drywall for an initial test. If the walls have sill-seal and the drywall doesn't touch the concrete, you may be in luck. If mold is confined to just under the flooring in limited areas it's not devastating. If you set up fans after you pulled up the flooring, Serv-Pro will have to clean everything in the house. Get tested to confirm all mold is removed before re-construction.

Heat source is a small natural gas fired boiler.  Since pump, with balancing manifold in a closet with 6 or 7 loops.  There is no chance of baseboard due to the weird layout of the house and the fact that it's on a slab.  No attic, either - some sort of California Contemporary style, with the little casement type windows up high*, and cathedral ceilings everywhere except in the hall, and that's too small to get into if there even was an access panel.

A big part of the standing water problem I believe is that the gutters have downspouts at the back corners of the house, where all the water is collecting.  My FIL added extensions to direct it away from the house by a good 6 ft or more, but it has nowhere to go.  I'm going to call a local gutter company and have them put a new gutter on each side, oversized if necessary, with downspouts only toward the front of the house so they can be extended past the shrubbery (like the last pic I posted) to where the lawn slopes away.  

My FIL even added a middle downspout to that long one in the picture, and piped it away from the house, but from what I can tell, it's still emptying into the big sunken area between the bushes and the house.  That big oak tree has roots that create a dam at the end of the 'deck'.  I really think that's a major contributor to the water issue, and I think new gutters with no downspouts in that low area could help at least somewhat.  

Random thoughts...

Around all inside and outside wall perimeters seems like a lot of mold for a system that holds pressure for a day, the tubing would have had to fail at every turn, no?

Is it possible the floors were flooded at some point and what you're seeing is mold from that?  

Is there similarly moisture in all the places you're finding mold?  Can you apply clear plastic sheeting over the expose slab areas and pressurize the system and see if you get any moisture under the plastic?  

Are there any zones you can disable or ways to separate rooms so things can be broken into smaller pieces for pressure testing?

I've turned off the boiler and the feed water valve, taken a pic of the pressure gauge, and will go back in 6 hours and again in 12 hrs to see what it's doing.  Better to be armed with information than to guess at the bleed down time.

There's no way to temporarily cut off a loop.  I was going to break the floor in the area where I first found water under the parquet tile, but there's water in random spots all over.  And not necessarily where the tiny expansion cracks are.  

I don't know if it's possible, but it occurred to me that if I could inject dye into the loop water, I might be able to see where it's coming up, if it actually is coming up anywhere, which I don't even know for fact.  It could be leaking down instead of up.  Or not at all, as MstrCarpenter postulated above.

As to the mold, the ServePro guy said it wasn't mold.  Probably more like discolored glue, or possibly from nails through the sills into the slab and/or reinforcement mats in the concrete.  It's crispy and hard, not slimy and finger-staining when touched.  So that's good (enough) news for me.

[Roly]

Heat source is a small natural gas fired boiler.  Since pump, with balancing manifold in a closet with 6 or 7 loops.  There is no chance of baseboard due to the weird layout of the house and the fact that it's on a slab.  No attic, either - some sort of California Contemporary style, with the little casement type windows up high*, and cathedral ceilings everywhere except in the hall, and that's too small to get into if there even was an access panel.

A big part of the standing water problem I believe is that the gutters have downspouts at the back corners of the house, where all the water is collecting.  My FIL added extensions to direct it away from the house by a good 6 ft or more, but it has nowhere to go.  I'm going to call a local gutter company and have them put a new gutter on each side, oversized if necessary, with downspouts only toward the front of the house so they can be extended past the shrubbery (like the last pic I posted) to where the lawn slopes away.  

My FIL even added a middle downspout to that long one in the picture, and piped it away from the house, but from what I can tell, it's still emptying into the big sunken area between the bushes and the house.  That big oak tree has roots that create a dam at the end of the 'deck'.  I really think that's a major contributor to the water issue, and I think new gutters with no downspouts in that low area could help at least somewhat.  


I've turned off the boiler and the feed water valve, taken a pic of the pressure gauge, and will go back in 6 hours and again in 12 hrs to see what it's doing.  Better to be armed with information than to guess at the bleed down time.

There's no way to temporarily cut off a loop.  I was going to break the floor in the area where I first found water under the parquet tile, but there's water in random spots all over.  And not necessarily where the tiny expansion cracks are.  

I don't know if it's possible, but it occurred to me that if I could inject dye into the loop water, I might be able to see where it's coming up, if it actually is coming up anywhere, which I don't even know for fact.  It could be leaking down instead of up.  Or not at all, as MstrCarpenter postulated above.

As to the mold, the ServePro guy said it wasn't mold.  Probably more like discolored glue, or possibly from nails through the sills into the slab and/or reinforcement mats in the concrete.  It's crispy and hard, not slimy and finger-staining when touched.  So that's good (enough) news for me.

Rent or borrow a thermal imaging camera, that will tell you if it is the heating system, new or old leaks that is coming through the slab.  You can also tape a plastic sheet over the suspect areas and see if there is is water vapor present but that wont say where it is coming from.  Run the heat for a while to use the thermal imaging camera to mark out the pipe layout.  Roly

[Robert Adams]

It really seems to be an issue of not enough drainage around the house. You should have several inches of concrete visible before any wood on the outside of the structure. Since your issue is around the outside walls and the way it was built I would focus on this area.

      Like mentioned a thermal camera will help or dump a bottle or two of UV dye into the system, pressurize it and after a day or two start looking at those areas with a black light. It's possible the dye might pass through cracks in the concrete to be visible.

[Phil Thien]

It really seems to be an issue of not enough drainage around the house. You should have several inches of concrete visible before any wood on the outside of the structure. Since your issue is around the outside walls and the way it was built I would focus on this area.

      Like mentioned a thermal camera will help or dump a bottle or two of UV dye into the system, pressurize it and after a day or two start looking at those areas with a black light. It's possible the dye might pass through cracks in the concrete to be visible.

Yeah, it sort of looks like a shovel-ready project, or at least that is the first plan of attack.

My daughter looked at a house a few years ago that had drainage issues, the people were selling it cheap but we passed due to location.

But the guy that did buy, actually corrected it over the course of a summer, all by himself, using only a shovel or two with an occasional friend.

[TDKPE]

A couple more views.

   
From the south

Very slight pitch to either side, mostly to the right (east).

   
Looking west, at the church and the elevated grounds.

Those trees have lifted the ground over the decades, and while not really visible in the picture, the last 1-1/2 ft near the house drops down suddenly.  Looks like someone dug down around the foundation, but all that's done besides getting the grass off the wood is to create a little moat.  I think it can be dug down and toward the camera to where there is a little bit of slope away from the house.

I like the idea of injecting UV dye.  I'm looking into that.

[Robert Adams]

Yeah there is a slope from those trees to the house. It's surprising how much they raise the soil around them over many decades.

       Might be frenchdrain time but no idea where you need to run it to or run it to a dry well. I need to do drains for our gutters etc but I have to go about 200 feet from the house which means allot of drop which realistically means the way ours is I have to do a sump pump and pump it.

[TDKPE]

Yeah there is a slope from those trees to the house. It's surprising how much they raise the soil around them over many decades.

I gotta wonder what they're doing to the foundation of the house.  There are giant trees all around it, most of which are close.  Great for shade, not so great for leaves and maple tree helicopters and birch tree 'caterpillars'.  

[Snipe Hunter]

Rent or borrow a thermal imaging camera, that will tell you if it is the heating system, new or old leaks that is coming through the slab.  You can also tape a plastic sheet over the suspect areas and see if there is is water vapor present but that wont say where it is coming from.  Run the heat for a while to use the thermal imaging camera to mark out the pipe layout.  Roly

The thermal imaging will show wet insulation in the walls also. With the wood siding in contact with the ground, there my very well be wet insulation. Assuming that's where the water source is. HD sells both a Pin and a Pinless General Tools moisture meter. The Pinless will give a real good idea of where there's moisture without putting pin holes in the wall and also where the concentration of water is in the slab. So check the upper walls or ceiling first to get a baseline of a normal moisture level and then start working your way down the walls and to the floor.

A couple things. Wood siding should be 4 to 6 inches above the ground. And the grading should be sloped downward away from the foundation all the way around and leaves/debris should be kept away from the slab. 

That being said... The slab will collect condensation on the floor all summer long and around the perimeter, at the exterior walls in the winter because it's the coolest area of the floor. Air conditioning is a must with slab on grade construction to decrease condensation on the slab. I'm not at all surprised to see mold under the wood and warped wood. Wood flooring should never be installed on a slab floor, no wood floor manufacturer approves it. Tile it or use water proof vinyl. Even the base of the interior walls (Sole plate) should have a vapor barrier between it and the slab and drywall shouldn't touch the floor. May not be code there but it is the "best practice". A slab should be poured over a bed of compacted gravel/stone and over a vapor barrier to stop moisture wicking through the concrete but it won't stop condensation on the top surface. Who knows how it was poured. If the drainage isn't sufficient, the air voids under the slab will just fill with water and wick through the slab.

[TDKPE]

I shut the heat off and the feed water to the boiler, and took these photos.  

   
Baseline, 0 hrs

   
3 hrs

   
24 hrs

Looks like 5 psi at 24 hrs, but accuracy is pretty iffy on a 90 lb gauge.  Why they use a 90 lb gauge is another question, but I've seen that on other small boilers, too.  The pressure regulator is marked 12 psi.  

   

Maybe I should have closed the valve on the expansion tank, to get a better sense of how fast it bleeds down, but I can give that a try (FWIW) when I go back to rip up more flooring.

[Roly]

I shut the heat off and the feed water to the boiler, and took these photos.  


Baseline, 0 hrs


3 hrs


24 hrs

Looks like 5 psi at 24 hrs, but accuracy is pretty iffy on a 90 lb gauge.  Why they use a 90 lb gauge is another question, but I've seen that on other small boilers, too.  The pressure regulator is marked 12 psi.  



Maybe I should have closed the valve on the expansion tank, to get a better sense of how fast it bleeds down, but I can give that a try (FWIW) when I go back to rip up more flooring.

Is the temperature gauge working ?  Seems like after 24 hrs it would drop quite a bit which could account for pressure loss.   Roly