How To Clean Up After Your House Has Been Flooded

The floods in Tennessee got me thinking about how to DIY a flood cleanup. I went to a ServiceMaster Clean owner and he, of course, recommended getting professional help, but he also gave some good advice. Read the interview here.

If you've got anything else you want asked, post it here and I'll try and put another Q&A together.

Horus.

Since I have asthma, I don't do well around mold. But I think many of us are overly concerned about "toxic mold" in flooded homes because of media stories, similar to the way that "killer bees" are also blown out of proportion to their actual risk overall.

I've never lived in a flood prone area so I don't have much experience with it, and one thing which I read and that surprised me after Katrina is that flooding--even for a lengthy time--does not necessarily compromise wooden houses structurally. Sure, mold will eat up the drywall, insulation, carpets, etc. but the framing will often hold up all right. Modern plywoods are supposedly quite robust, too, but the adhesive in older plywoods (pre-1970, IIRC) don't hold up to moisture that well. Anyway, for what it's worth.

Dealing with hurricane damaged roofs and rain coming in, often in largge quantities, getting rid of the bulk water is the first concern. Pumping, squeegeeing out, and/or vacuuming up standing water is a good start. Ripping up carpets and carpet padding and any soaked upholstery is the next step.

After that drying out the interior by 'thermal pumping' seems to work pretty well. The idea is that you crank the heat wide open, then you crank the air conditioning wide open, rinse, repeat. The idea is that raising the temperature gets the moisture into the air where the air conditioning can squeeze the air dry and drain the water away.

You can speed and intensify heating by electric heaters. And dry the air faster by running dehumidifiers. This dry air speeds evaporation. When the dry air is heated and circulated it soaks up water quite rapidly.

Getting the water out as fast as possible is good because it gives less time for mold to form and grow. Opening up the walls by removing at least one side below the water line helps.

Three times - in 2004, 2005 and 2006, I helped people clean up after river floods. I pumped out their houses, shoved mud out of their living rooms and hauled mountains of soggy sheetrock and insulation out of many homes, many times.

Here's what I learned.

1. There is very little you can actually salvage. Anything porous is generally ruined forever unless you go with some seriously high effort restorations. Throw it all away, it's going to become a mold colony anyway. You can save most glassware, ceramics and metal. All electrical appliances and fixtures are ruined - they may seem to work, but there are many dangers lurking in an electrical device that has had silty water pass through it. Oxidation is a Very Bad Thing in electrical equipment - it leads to fires. Oh, and your ammo - unless it was water-tight, it's ruined too.

2. Oil is the enemy. Many basement oil tanks were not secured to the floor and didn't have proper check valves, so the oil came out, floated all around the house and then left a coating on everything as the water receded. In these cases, the whole house because a hazmat site and requires special cleaning crews with oil separators on massive vacuum trucks.

3. More to point one. The first time, people who flooded tried to just replace insulation and wallboard. They quickly learned that the entire electrical system - every plug, every switch, every wire cap - was compromised and needed to be replaced. The next time, they tore out everything but the floors to the studs, leaving only the plumbing - and they learned that most floor underlayments are like slow giant sponges that swell and rot with mold about 2 weeks after you move back in. Strip it to the studs and pipes.

4. You will need to dry the home drier than you can imagine before you can think about rebuilding. This may not be possible without a considerably large level of equipment, but alt least open every door, every window at every level and start a cross-ventilation. Your own electric service may be out for weeks, you'll need a generator to run the fans. Once the electric comes on, run air conditioners and/or dehumidifiers for a LONG TIME - like 14 days. DRY THE HOUSE DRIER THAN YOU THINK YOU NEED TO DRY IT.

5. You can goof around for a while with fans and dehumidifiers, but eventually, you'll get a Thermal Energy System. These are basically giant (and I mean giant, like truck mounted) propane or electric hair dryers that blow hot, hot air thorough your home for 24-72 hours. Nothing comes close in terms of speed and effectiveness, but, of course, this is the highest cost option in the short term. But hot air is an incredible moisture wick.

6. Your yard may be toxic. Depending on what washed down from where, you may find that the sludge on your property is incredibly toxic for you and your pets. You may need to have the top layer of muck hauled away.

7. If you have a water well, it is likely contaminated with any number of things from septic tank overflow to paint to pesticides. Don't drink from a well that had a flooded wellhead until you get a through check for safety.

8. Your foundation may be compromised. You need to make sure that the ground didn't soften around your house while the basement was still full of tons and tons of water pressing OUT on the foundation. We had two homes suffer a collapse of the gable ends of the foundation after the flood waters receded and the basement was pumped out - the walls pushed out, the load above was floating a bit and as the load came down on the foundation, the pressure from above collapsed the foundation. Not a good scene.

Sorry, it's depressing, but the best thing to do is not live in a flood plain, and if you do, live in an elevated, flood-resistant property. More than a few people opted to elevate their homes after the last flood.

Hi Martin,

I appreciate the info. There have been many, many people in middle TN who have experienced flooding. I'm helping one of my wife's coworkers with her house while she stays with us. It doesn't get much worse than removing flooded insulation and ductwork in a crawlspace.

I was interested in the info on the appliances and electrical system. She was planning to relocated a flooded but working refrigerator in her garage when she gets a new one, but I will now advise against it and also reworking her electrical.

The flooding here was unexpected and severe. One person drowned on Interstate 24. Who would have thought? Many people who lost their homes did not live in a flood plain and did not have flood insurance. Many businesses and landmarks were also inundated. The good news is that pretty much everyone has been well-behaved, looting and scams have been small scale.