Inspectapedia is not too keen on ozone generators.

You sound to me like you're on the right track.

Thanks for that link, Worthy. I was hoping you'd chime in here. Guess I need to do some more research.

On a more positive note, dh thinks he has found a place where he can gain access into an air duct that runs to the room in question, from an unfinished closet in the basement. His hope now is that he can remove a portion of the duct and use a flashlight to try to see how that part of the foundation was built. At least we'll know more about what we're facing.

Dh also suggested that should we need to pull up some of the hardwood floors, he could put in a transition section beneath the cased opening to the room (a double run of floorboards would be the same width as the trim.) I know that may be looking pretty far ahead, but at least I won't worry about how the space will look when we put it back together.

Meanwhile, I'll try not to borrow trouble and get back to reading up on possible solutions.

I hope our long time member lkplatow doesn't mind me posting the link to her site. She had water/mold issues and did a great job of documenting her ordeal ... a great resource for other homeowners.

http://www.imageevent.com/platow/defectivehouse

I hope you can resolve your problem easily, but water issues are never quick or easy to resolve. Good luck.

Thanks, Chispa. I remember reading that site while our house was torn up before. It's quite shocking.

We've finally gotten some heat relief, which makes it pleasant outdoors but presents a problem inside. While the temps are 50s at night and mid-70s during the day, making both heat & A/C unnecessary, the current humidity is 80% so our dehus are all running full tilt. I looked into having dehus installed on each HVAC system, but at approx. $3K a piece the cost was prohibitive. I also wasn't sure how well they'd work in the shoulder seasons when neither heat or A/C are called for and we just need ventilation & humidity control.

I like the stand alone dehumidifers better than ones
incorprated in to hvac system. When you place the dehumidiferes in the conditioned space they sense the
RH in that space, many central dehumidifiers sense the RH in the area they are located in and do not dehumidify the conditioned space as well.

Where are you located?
Where are central units located?
Have you talked to hvac company about adjusting
dip switch settings? Many times they are installed
with factory settings and need to be adjusted for your climate.
ERV's are usually not for cold climates..that would be an HRV, so I wonder about your location.
Also ERV's are for 'tight' houses..with less than .25 air changes per hour. If your house is not at this level of air tightness the ERV can bring in moisture adding to the
dehumidification load of hvac.
Was the house tested for air tightness with a blower door?

To 'see' what is happening behind the walls and between floors of your home would require a thermal scan of your home. This will show you moisture intrustion sites
and moisture in walls, ceilings and floors.
IMO this will be the way to go to actually KNOW what is happening. Then whatever the IR scan shows will be on you to address. Around here (Louisiana) thermal scan (InfraRed)
scans are used often when home owners and builders are seeking solutions. I've even seen them used in court cases.
But hopefully...it won't come to that!

best of luck.

Thanks, Energy-rater. I wish you had a clone in our area. We're in the deep south (but not LA) which is why I chose the ERV over the HRV. The house is less than 2 yrs. old, so we took for granted that it's pretty tight. I called a bunch of HVAC and related companies, and none does a blower door test nor could anyone refer someone to me.

I did have an IR scan done last year in 7 or 8 rooms, but not the entire house. I could only locate one person who does it, and you can guess that he charges a premium with no competition. It was not as helpful as I'd hoped. Maybe it would be better to try again in the winter.

Guess I'll start shopping for a few more portable dehus. Dh has a plan to create a little closet, with louvered door for air flow, for at least two of them where the drain hose can be run either outside or to a floor drain. That should reduce the noise.

rockmanor, your local utility company many have referrals.

If you are in northern Alabama I can refer you to an energy audit guy here. And in the Atlanta area SouthfaceHomePerformance.com has a list of contractors.

Not rubbing it in. But in the jurisdiction I build in, the builder is responsible for remediating water penetration problems for the first two years. If the builder doesn't, the mandatory warranty programme takes responsibility.

(Or is that unacceptable socialism?)

It might be worth consulting a lawyer. If the builder took "several attempts" to stop the roof leaking, there's a strong argument for all of this being due to his (or her) negligence. Whether or not there's a strong LEGAL argument is another issue.

Alabamanicole, our power co. people are clueless. But thanks, anyway. If we retire in N. AL. one day, I will certainly want to speak with your energy audit guy.

Worthy, don't rub it in! The builder of this house turned out to be a total flake. I've never known a grown man to cry (yes, actual tears) and whine as much as he did. If he'd threatened suicide one more time I would have handed him my Glock. At least he isn't building any more. Sorry to be so harsh, but he endangered the lives of two of my loved ones, compromised the health of the rest of us, wasted time that could've been spent solving the problems by making excuses and ultimately cost me money that I couldn't spare.

Do you think that your Mike Holmes might enjoy a trip south this winter? He's filmed in other parts of the States; maybe he'd enjoy some mint juleps and magnolias.

That site linked is heartbreaking.

Here's a cheap thing that might help -- caulk around all the outside windows, doors, vents, etc. I will bet almost anything this builder didn't bother to do it, and water could be getting behind the walls when it rains. The water that gets in won't necessarily show up near your inside windows.

One way to spot check cheaply for moisture in the walls is to remove outlets and switches and check for dampness behind them.

OP there is a national energy raters site

www.natresnet.org

theirs is the standard we all adhere to.

Not only is house tested for air tightness, but ducts
and return air are also tested for tightness.
thermal scans (IR cameras) area also available.

not only do you need to find the moisture entrance
but how to repair this site.
Most energy raters give recommendations as to how
to repair.

IMO this is where you need to go.

best of luck