We bought our home less than two years ago; it was a new builder's spec. During the first six months we experienced roof and chimney leaks that took several attempts to stop. I also thought I detected a musty odor in several rooms, but didn't find the leaks for a couple of months longer, since only one left a sizable puddle that was hidden by furniture. Windows and doors have been replaced or reinstalled after treating. We removed trim, drywall and insulation from some walls, cleaned and treated the wall studs, put in new insulation, and re-drywalled. Anything (such as windows or baseboards) that was reused was cleaned with Jomax products, and not installed until moisture readings were single digit. When we removed drywall or wood, we went 18 - 24 inches beyond the last sign of mold. The builder is now out of the picture. We've spent $$$$$ on correcting drainage issues as well as these leaks, and are tapped out. I'm not trying to plead for sympathy, but want to explain why whatever I do next must be budget-friendly.
When I first found the various water intrustion problems my dh could not smell anything but I could smell a musty odor. I now smell a similar odor again, but can't pin down its source; dh smells nothing.

The builder installed the usual builder-grade single stage 13 SEER HVAC systems that are most likely oversized (that's common around here) as their run cycles are too short to effectively dehumidify. The ducts were professionally cleaned after the repair work was completed. We run multiple portable dehumidifiers around the house and try to maintain the RH below 45%. We installed good 5" media filters and UV lights on the HVAC systems, plus an ERV on the main floor. I've kept the ERV setting at just 10% for the past two months because of excessively rainy weather, otherwise the RH gets too high.

The room that concerns me now is not the one that had the worst mold problem before. The odor is stronger near the fireplace (north wall) and in the southeast corner (there are windows on the east wall but not on the south wall.) I see no sign of water instrusion. Moisture meter readings taken in the baseboards and window trim range from about 6% to 13%, with most locations giving single digit readings. In comparison, before all of the work was done I found moisture meter readings exceeding 30% around most of the windows and doors and along the baseboards beneath the windows.

I recently replaced the (temporary) curtains with plantation shutters. The only remaining upholstered furniture is a sofa and loveseat, neither of which have any odor. The floors are hardwood and there's no area rug. So that eliminates any easy answers.

One unknown about the house is the foundation under this room. The lot slopes, and beneath most of the main floor is a finished basement with poured concrete walls. We've had no trouble in the basement, except for the french doors (that we've replaced.) What's beneath this room we have no idea; it could be slab or a very low crawl space or something builders here refer to as a raised slab. We'd likely have to pull up the floor to know for certain. There are several HVAC registers in the floor, which we've never seen in a slab foundation. There's only about a 5" step down to the adjacent patio which is on grade. The patio often retains water for 12 - 24 hrs. after a storm, and it's possible that some seeps down along the south exterior wall.

One fear is that some mold spread beneath the floor previously and was reactivated/encouraged to grow by the constant rain we've had these past two months. The other fear is that mold has grown around the firebox and chimney, and/or beneath the hearth where water may have seeped during the earlier leaks. I don't have a clue how to be sure, short of tearing apart the house.

I've read about ozone machines that can be set up in a sealed space to run for one to several days and are supposed to kill mold/mildew. They're pretty costly to buy and I haven't had any luck finding a rental around here. Has anyone used them with good results? Do you have any suggestions of how to proceed?

The remediation work involved many of the same steps that you described.

As for some help in solving your mystery, I've provided a link below to an excellent book that covers many possible sources of mold problems. The title of the book sounds alarmist but the book itself is not. It's written by an industrial hygienist that has inspected hundreds of homes. Sometimes the solutions are easy and inexpensive.

You might be able to find it at your local library. That's where I first found a copy after reading some positive reviews on Amazon.com. Later I ended up buying a copy from half.com. And now there are some very inexpensive used copies for sale through Amazon.

Also note that it's not at all unusual for different family members to react differently to airborne contaminants. The industrial hygienist that tested our home told us that also. He told us that he'd seen cases where everyone living in the house is fine but it was a friend or relative that had a problem.

When we had high mold spore levels in our home, my wife had the strongest reaction. She felt that she could almost taste something in the air and her lungs had a tightness when breathing in the house. She had no problems outside the house and at other people's homes. It was her insistence that something was wrong that led to our house being tested. To me, the air seemed fine and I couldn't sense or smell anything unusual. (It was only in retrospect that we realized that we all had some health related problems at the time. This included our two young children. I will not draw a definite connection between the mold and our health issues but the timing was certainly unusual.)

In the end, we found out that we had mold growing inside our walls and that an unducted return air path for our HVAC system ran right through the problem area. Our HVAC system pretty much acted as a mold spore distribution system.

Fortunately our home was fine after the clean up.

Good luck with your home!

Bob

Our county library system is much the same. It's like having one huge library.

One other thing to mention is that pretty much everything was removed from our home for the remediation effort. If it couldn't be washed or effectively cleaned, it was discarded. We ended up replacing all of our carpeting and all of our fabric blinds.

On the ozone machines, I've read that they are often used for smoke damaged homes. You might want to check with local companies that do that type of work. Perhaps the industrial sized machines do a better job than the ones that sunnyca tried?

Bob

Over on the building forum, Worthy steered me clear of the ozone machines. Besides, I know that we really need to get to the source.

Our next experiment will be for dh to try to remove a portion of an HVAC duct that he can access from the basement to see just what the foundation is of the room that worries me. We don't know if it's slab or crawl space or some sort of hybrid. Unless he has to leave town (family crisis pending) he will do that this weekend. Cross fingers!

We had a problem similar to yours, but fortunatley not as extensive, although it persists despite aggressive and expensive mold remediation.

LOL

But the caution is that these types of inspections can be very expensive. Our insurance company paid for all of our inspections and they ran about $2,500 each. These were conducted by an industrial hygienist.