Launch Slideshow

On Site with Habitat for Humanity

Note: The building I visited was flooded by relatively clean water from an adjacent creek, so the work documented here is a best-case flood scenario. If the building had been filled with water containing sewage or notable chemical contamination, the amount of building materials torn out might have been much greater. And the personal protective equipment worn by the personnel on site would have likely have included rubber boots and gloves, Tyvek suits, and respirators instead of the more casual work gloves and dust masks.

On Site with Habitat for Humanity

Note: The building I visited was flooded by relatively clean water from an adjacent creek, so the work documented here is a best-case flood scenario. If the building had been filled with water containing sewage or notable chemical contamination, the amount of building materials torn out might have been much greater. And the personal protective equipment worn by the personnel on site would have likely have included rubber boots and gloves, Tyvek suits, and respirators instead of the more casual work gloves and dust masks.

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    On exterior walls, wet drywall is removed to a height of four feet but furring strips are left to dry in place. After this photo was taken, the beadboard insulation was also removed to aid drying.

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    On interior walls, wet drywall is removed on both sides.

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    The studs are left in place to dry.

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    Wet fiberglass insulation in the wall is also removed.

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    HVAC ducts need to be drained and cleaned well. Where the window trim is left in place, note that a strip of drywall two inches wide is left to provide enough surface to tape and patch the joint.

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    Cutting out corner bead is tricky. An angle grinder with a thin cutoff wheel would be my tool of choice; second best would be an oscillating multi-tool fitted with a metal cutting blade. Third choice would be a reciprocating saw with a very fine tooth metal cutting blade.

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    Wet wood will have to be treated and dried thoroughly before new drywall can be applied to prevent the growth of mold.

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    Electrical wiring in conduit presents a special hazard as it can fill with water. This loop of conduit could be holding water just like a trap in a plumbing drain; it needs to be inspected and possibly re-done.

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    This receptacle seemed fine but blew up after a few minutes of use due to water in the electrical box, conduit, or the device itself.

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    Even when dried out, flooded electrical devices could contain sediment or other fine debris ...

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    ... and should be replaced.

(Boulder County Colo. -- Zero plus 14 days) To gain access to a flooded basement site buzzing with clean up activity, I tagged along with the local Flatirons chapter of Habitat for Humanity. They were busy the week after the flood overseeing groups of volunteers that were cleaning up their own up community and religious buildings. Habitat for Humanity prioritizes helping non-profit organizations and these groups are no strangers to Habitat's mission, as they often work as community partners and provide volunteers for Habitat's projects year-round. Next on the list comes low-income housing, which will likely keep the Flatirons chapter busy for quite a while.

I visited a site that was undergoing the second stage of clean up. After pumping and mucking out a flooded basement, wet and contaminated building materials must be removed quickly both to reduce the habitat for mold and to remove the residual moisture in a building.

Flooring

Soaked carpet and padding should be the first thing to go. Cut it into strips a few feet wide, roll up as much as you can handle, and crosscut the strip. For carrying these dripping wet materials upstairs and through finished living space, cut rolls only as big as you can put in a bucket or garbage can to reduce the mess. For hard flooring, common sense will dictate what should be removed. If sewage was present in the floodwater, it is probably safer and easier to remove most flooring and start fresh rather than to clean in place. For "clean" floodwater, it depends more on the water damage. Vinyl flooring might be just fine, but of course hardwood floors won't be worth trying to salvage.

Drywall

Drywall needs to be torn out at a level at least several inches above the height of the floodwater. For shallow flooding, some people skimp here and only remove a foot or so, but that means patching and finishing work will all have to take place with workers on their knees. This approach seems a bit short-sighted and will probably add labor expense in the name of saving some money on drywall. The professional approach (for flooding under four-feet deep) is to deeply score the existing drywall 48 inches above its bottom with a utility knife and pry it off the wall from the bottom up.

Wood

Studs and furring strips are often left in place to dry out. As long as the wood is sound and dry, it should be okay. Any wood in direct contact with concrete (such as furring strips and floor plates) will hold moisture for a long time and should be treated with an appropriate chemical treatment to dry and disinfect it. The use of a moisture meter is important for determining when the wood is dry enough to re-cover with drywall. (More on treating and drying wet wood in my next report.)

Insulation

Fiberglass insulation that has been soaked should be cut out a discarded. Less porous foam insulation is often left in place to dry out, but not in all cases. Closed cell and open cell foams offer no food for mold to thrive on, but make sure any wood the foam is in direct contact with is dried and treated since the foam can hold the moisture in for a long time. For the same reason, concrete walls behind foam insulation should be given enough time to dry thoroughly before drywall is put back on over the insulation. in most cases, this will require removing the foam, then replacing it after the concrete has had time to dry.

Editor's note: The treatment of foam described in this section has been revised since this article first appeared.

Michael Springer interviews Phil Dorth, Director of Construction for Flatirons Habitat for Humanity, which serves the Boulder Valley School District in the city and county of Broomfield, Colo.

Electrical Wiring

According to the Habitat for Humanity foreman, Romex-type non-metallic cable and plastic boxes should be okay to leave in place, but don't trust any electrical device that has been underwater. Flooded receptacles and switches should be replaced. Even if they dry out completely, sediment and other fine debris from the flood water could have washed into a device and lead to insufficient contact or shorting.

Conduit and armored cable can hold water inside and present a greater danger. Do not use these circuits without inspecting for soaked wiring and consulting an electrician for help.

While I was at the Habitat site, a volunteer using a shop vacuum illustrated the seriousness of this danger pretty effectively, and got a good scare in the process. After running the vac for a minute or so plugged into a receptacle wired through conduit, the device exploded with a flash that lit up the room like lightning. The plastic face of the receptacle was incinerated, leaving bare metal contacts visible. I'm not sure if it shorted out due to water in the device or conduit or what, but it made the point clear.

HVAC Ducts

Ducts that were underwater should be dismantled and cleaned out or replaced.

And don't forget to clean out the bottom of the furnace cabinet and dry it out. If water made it up to the blower or pump motor, it may be ruined, but get a professional opinion on the state of the furnace and hot water heater.

Keep checking back for more coverage. Chemically treating and drying out a building is the next step in the process, and I have information coming from local, state, and federal building officials regarding some standards that are being relaxed during this state of disaster.

This is the third in a series of reports intended to help inform both the victims of natural disasters as well as the contractors they look to in these times of crisis.