What is kept and what is thrown away after a basement flood?
Hard materials such as concrete, masonry and metal can usually be cleaned and kept. Porous materials that soaked in floodwater, such as pad, cardboard, particle board and paper, are usually removed.
The decision turns on what the material is made of and how long it was under water. Concrete can be washed, dried and kept, and a steel water heater or a metal shelf can often be cleaned and used again. Drywall, pad and wood that stood in silt are usually removed, because the silt cannot be fully cleaned out of their fibers.
Stored items in the basement need the same test. A box of paper or a carpet that sat in floodwater is removed, and a sealed plastic container or a metal tool can often be washed. The owner decides on anything of sentimental value, and the decision is noted on the record.
Why do the walls need so much attention after the water has gone?
A foundation wall that was soaked from outside can be pushed, cracked or weakened, and it holds water in its masonry for a long time. The walls are read and dried, and any damage to the structure is reported for an engineer to assess.
Water pressure from outside a foundation pushes on the wall while it is saturated, and the wall can bow or crack. The clean-up does not repair the structure, but it does record any crack, bow or displacement it finds, so that a structural engineer or a contractor can assess it. The owner should not assume the wall is sound because it looks straight from the inside.
Masonry dries slowly and it gives up white salts as it dries, which is the efflorescence that shows on block walls after a flood. The salts are cleaned off once the wall is dry, and the readings show when that point has been reached.
How does the basement get dried after a silt flood?
Silt traps moisture against the surfaces, so it must be removed before the drying can work. Once it is out, the air moves across the cleaned surfaces and the readings are taken until the materials reach their goal.
Drying begins only after the silt and debris have been taken up. Air movers placed over clean surfaces do their job, while a layer of silt would keep the moisture under it. The dehumidifiers run for the room, and the readings are taken in the walls, the floor and the framing at the points where the water stood longest.
The equipment runs for as long as the readings require. In a basement with a high water table or a lot of masonry, that can be several weeks, and the record shows the readings at each check so the owner can see the trend.
What should the owner do in the first days after the water goes down?
Keep the power to the basement off until the panel is checked, do not run the furnace or the water heater until they have been looked at, and do not start pumping by hand without a plan for the water that comes back.
The furnace, the water heater and the electrical panel are the items most likely to have been under water, and they should be checked before they are used. A flooded electrical panel is a hazard, and it is the first thing to settle. Mechanical equipment that was under water may need its controls cleaned or replaced, and that is a job for the trade that owns it.
Avoid moving the water too quickly. Pumping a basement dry in one day can push the walls inward, and the groundwater outside can still be high. The sequence of pumping is part of the plan.
