Hurricane Harvey, which hit the Texas coast in August 2017, did some massive damage and dumped more than 50 inches of rain in some parts of the state. Houston got the worst of the flooding, and I’ve been asked every day since about my advice on how to clean-up. This blog post provides a quick overview of the post-flood clean-up process.
1. Protect Yourself First
Before we get into the specifics of the process, let’s take a minute to talk about PPE (personal protective equipment).
Most of the PPE is pretty straightforward, with rubber boots/gloves/clothes, but the most important gear I want to mention here is protection for your lungs. f the building was built before 1978, post-flood demolition work may involve lead-based paint that will become airborne during demo. Respirators are vital. And even if you are working on a newer building, at the very least you will stir up dust and mold that can be a major nuisance (or worse). At a minimum, use an N95 mask (around $3 each) respirator (I like the N95 with a venting port), or for the best protection, use a half-face respirator with a P100 filter ($7.50-10 ea.).
Next, be sure to check for hazards inside the house before beginning work. Cut-off power if electrical outlets have been wet, shut off the gas into the house, and turn off the water line at the meter (mainly so you don’t accidentally cut a gas or water line).
2. Demo and Dry
Remember that dampness supports mold, bacteria, and pests, so trash out anything that’s wet and can’t be dried. Carpets and pads are probably trash if this is a flood from outside the house, as the sewage is tough to clean out of carpets. Cut drywall one foot above the flood line and remove all the wet stuff below. Cut the insulation where it’s dry and don’t yank it down or you’ll be left with gaps above. Hardwood floors might be able to be saved but it’s touchy. Typically, you'll have to demo to the studs and to your concrete slab. You might be able to be save some solid-wood trim and cabinet cases, but any MDF or particle board (think Ikea cabinets) are trash after a flood. And cabinet doos will probably have to be replaced
3. Clean & Disinfect
Once the house has been demoed down to the studs, it’s time to clean and disinfect. Use a broom and wet-dry vac to clean up silt and debris - get it really clean inside. You might want hose down the house with clean water if the flood water has been contaminated with sewage (which is typical). Since you've demoed down to hard surfaces, they can all get wet; studs, slab, and so on can all benefit from a hose down. This will help wash away bacteria. Don’t powerwash, and avoid getting the remaining dry drywall wet.
Next, use a disinfectant to kill the bacterial growth that happens from sewage in floodwaters. Microban is a good option but it’s not something you want to breathe in or immerse your hands in or get splashed in your eyes. Use your mask, gloves, goggles, and the like. Mix to the recommended dilution and use a pump sprayer to coat everything that got wet with a mist of this to kill all the bacteria. Another option is to use a bleach solution (roughly 1/4 to 1/2 cup bleach to a gallon of water) but be sure not to wet metals as they will corrode with the bleach solution. Keep kids and pets away during this disinfecting stage.
4. Ventilate and Dry
Now that the house is demoed and clean, it’s time to get everything dry again. Open all your windows and doors if it’s nice outside and get air flow going. Use fans to blow on the wet studs and surfaces. If you are a contractor, be sure to buy the Carpet Dryer fans. These fans blow tons of cfms and work for years. Otherwise, even a $15 box fan will move some air and speed drying. Remember that mold only grows where things are damp, so you want to get everything in the house as dry as possible as soon as possible. Consider a dehumidifier if you are closing down the house at night or if the weather is wet or humid.
5. Verify and Treat for Future Mold Growth
Last step before considering any rebuilding efforts is to ensure the house is dry. I use a Moisture Meter to probe the wood near the ground for moisture content. Ensure the whole house is below 20%, or ideally below 15% moisture content, before moving on.
Once it’s verified dry, then I’d recommend a final treatment to ensure mold won’t grow. I prefer BoraCare with Mold-Care, but Concrobium might be easier to source (it is sold at Home Depot). Both of these get be applied with a pump sprayer, and you should wet down the surfaces of all the building materials. There are less toxic ways to keep mold growth down in the future, but the most important thing to remember is to keep the house dry.
This article and video originally appeared on mattrisinger.com.
