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Re: Ozone for Water Damage Restoration

A Reader writes:

Hi Ed,

I've been solidly investigating HEPA air cleaners, vacuum cleaners, and dehumidifiers.

My house suffered water damage while my family was away.

Drywall, Insulation, Carpet Padding, and Carpet are ripped out. I've scrubbed the concrete floor with Mold-Killer and applied sanitizer.

The rooms still smell mildewy/moldy and I'm concerned for the health of my family.

So, I'm writing in hopes of gaining non-sales-biased guidance from you.

--Can I simply strap Filtrete 1900 MPR filter to the back of a fan, seal the room, and let it run instead of buying an expensive machine?

--Are there particular filters that ought to be used in a mold remediation situation?

--Any advice regarding germicidal UV lights (placed in duct work for HVAC intake and/or placed in the middle of a room)?

When the lights are turned off, and someone enters the room, will there be residual effects from the lights that would be damaging to health?

Thanks so much for your attention!!!

A Reader.

Ed's Reply

Hey Reader;

Water damage remediation is one area where ozone generators and ozone-based air cleaners are the answer.

A few years back I accompanied my son to inspect a 9-year old home he had fallen in love with. The house was in The Woodlands, an upscale commuter village north of Houston.

The property bordered on a big park/greenbelt, with a pretty creek running along the backyard.

The house was priced $65K lower than everything in the neighborhood, and very nice inside.

But something bothered me from the beginning. The outdoor AC housing and other metal parts were excessively weathered and the large below-slab-grade back deck and barbeque seemed to be older than the rest of the house.

Walking around the back, I finally saw it - cedar fence boards showed stains up to where the high-water line had been in the flood.

I loosened some siding and trim to inspect the framing. I was surprised to find sills and studs were rotted all the way up above the water damage line, maybe 20 inches above slab grade, all the way around.

I ran indoors where my son was ready to sign paper for a near-full price offer.

The very nice real estate lady suddenly remembered her obligation to disclose the truth - the home had flood damage when it was one year old. But insurance had covered the loss and professional water damage remediation contractors had been engaged for the cleanup - drywall and carpets had been replaced, surely everything must be fine.

Things were NOT fine. The structure may have looked fine to the water remediation contractor (maybe not?), but the damp wood dry-rotted in the ensuing 8 years. In my opinion the house was completely ruined.

You'll want to avoid this type of resale value debacle as you restore your house.

So your first concern with water damage cleanup is absolute removal of all moisture.

Mold odor is a symptom of lingering moisture. If you smell a musty smell (airborne mold spores), there is still water in the building.

Where? Under the sill plate, between stud backs and sheathing, in utility runs and AC runs/ducts. Anywhere there is a crack or dust to absorb moisture. Roof drains and gutters should not channel rain water anywhere near the slab/foundation/basement walls, as is often the case.

Many overlook areas where condensation occurs, like AC ducts and below windows in cold weather.

So your research with dehumidifiers might be the start. Sorry, I am not the authority on these products.

I'd wait for a low humidity day and air everything out.

Once you have hunted down every ounce of water, then use an ice pick or other sharp implement to probe all sills and stud-work for softness. Look for discoloration indicative of water penetration and potential mold infiltration. Water can be wicked up inside wooden studs as it was when they were alive.

When you are sure the moisture is gone, my suggestion is to use shock (high concentration) ozone in the unoccupied home for at least 24 hours.

While ozone doesn't penetrate walls, if concentration is high and time is allowed, it will seep into cracks and crevices where mold colonies hide. Running the HVAC fan will draw ozone through the duct-work.

The ozone generator should produce a minimum of 2000 mgph (milligrams per hour).

There are a number of these ozone machines still available, selling for around $500. Again I am not really an expert on the brands, and discourage the use of ozone in routine household air cleaners.

Rental ozone units are available for about $80/two days to $200/week including shipping.

See http://www.ozonesolutions.com/ (An example, not an endorsement, again, I really have no experience with these products or vendors.)

Another alternative in the water damage situation, if you are desperately short of cash, would be to look for an old ozone-producing air purifier on Craigslist/eBay/classifieds. Several brands could work, but would need more time than the professional ozone machines.

Old Sharper Image Ionic Breezes and Oreck XLs, both made before the ozone-guard/proshield catalysts were added, can be found in abundance for $80-100.

Ionic Pro (not the Turbo), a Wal-Mart model, also makes some ozone, maybe $30-$60 used.

Brookstone Pure-Ion was also a good ozone producer, I see some still around.

Ecoquest-type plate ionizers, sold under a number of brand names - Ecoquest, Alpine Air, Living Air, and numerous foreign-made knockoffs - are still widely sold.

My site has reviews of all these air cleaners. If you decide to go with a used ozone-making air cleaner, be sure to inspect the product carefully for electrical arcing and sparking before purchase.

You will be able to sense the electric-like smell of ozone at the discharge of any of the above which is working properly.

Product life expectancy and reliability was below average on these, so look for lightly used deals. These will make maybe 100-360 mg/hr ozone, so at least 72 hours will be needed to build ozone levels.

Air out the area for at least an hour after the machine is off before occupying the room(s).

I'd keep it up even after the mold smell can no longer be detected.

Once your restoration is complete, you could use the ozone air cleaner periodically to control odors. But I do not recommend using these when pets or people are in the home.

Of course you can make a poor-boy air cleaner out of any box fan, but these are best for visible dust reduction - don't expect much action vis the mold spores. The problem with box fans is pulling air through the front corners rather than through the filter. I have made several with cardboard overlays on the front corners to reduce front air back-filling.

UV lamps main safety concern is eye damage from looking at the light. So the kind that install inside the HVAC system - shining directly on AC coils and drip pans won't hurt - but I'd avoid deploying/working around direct UV lights in the rooms.

I doubt that any residual effects linger after UV lamps are off. They were formerly used to sterilize instruments and tools in several applications. I remember UV lamps in barbershops, for instance.

While rebuilding, I recommend you consider alternatives to carpet - like hardwood floors or ceramic tile.

Latex used to float/seal and paint new drywall should also be examined - non-toxic alternatives are slightly more expensive, but a good investment. My youngest son bought a brand new house a couple years ago. I have been refilling his Sharp Plasmacluster's carbon filter bags every 6 months. After two years, they still stink of cheap latex after about 90 days running.

Best wishes,

Ed

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