Heavy Rain and Flash Flood Cleanup: Steps From Extraction to Drying

How does heavy rain get into a house so quickly?

Rain that falls faster than the soil and the drainage can take it runs across the ground toward the house. It then finds the gaps at doors, low walls, crawl space vents and the slab edge. Grading and gutters that send water to the foundation make this more likely.

A short, heavy storm can fill low points around a house within minutes. Water that cannot drain away sits against the foundation until it finds an opening. A door threshold that is lower than the ground outside is a common entry point, and so is a vent in the crawl space.

Gutters that overflow and downspouts that discharge at the wall add water to the same place. Once the water is against the house, it can move under a door, through a gap in a wall or into the crawl space, where it spreads under the floor.

What makes flood water different to handle?

Water that has come over the ground can carry silt, debris and sometimes contamination. It is handled with more care than clean roof water, and the materials it soaks are more often removed. The steps are the same in outline, but the care at each step is greater.

Rain that enters through the ground is treated more carefully than rain that comes through a roof, because it may bring silt, soil and other material into the building. The crew wears protective equipment and uses a more careful cleaning of the surfaces that stay.

Porous materials that have been in the water are the most affected. Carpet, pad, insulation and the lower part of drywall are removed more often. Hard surfaces such as tile and sealed wood can be cleaned and kept if they dry to readings.

What should you do in the first hour?

Get people to a dry level and out of the water, cut the power to wet areas if the panel is dry and reachable, and move valuables and furniture out of the water. Photograph the water and the damage before anything is moved, then call.

Do not walk through standing water near outlets or wiring. If the water is in a room with a live appliance, leave the power alone and keep out. A household vacuum is not safe on standing water, because its motor and cord can fail.

Keep a short note of when the rain started, when the water came in and where it came from. Those times help the crew decide how long the material has been wet, which affects which parts can be dried and which must come out.

A house that is still taking water in a heavy rain needs more than the drying plan. Tell the line whether the water is coming through the ground, a door, a window or the roof, because each route is covered differently. If the water is rising across a floor, get people to a higher level in the house and stay out of the wet area until the crew has arrived and checked the power.

How is standing water removed?

Standing water is removed with pumps and wet vacuums. Silt and mud are cleared as the water goes, because they hold moisture and block the equipment. Removal is done quickly, since water spreads into the subfloor and wall base while it sits.

The crew starts at the lowest point and works toward the door, so the water is not pushed into dry rooms. Garages, crawl spaces and basements are each handled as separate spaces, with their own equipment and access.

Once the standing water is out, the floor is checked for silt, debris and the level of wet material beneath it. The next step depends on what the check shows.

Which materials come out and which stay?

Materials that cannot be dried to readings are removed. Carpet and pad that have soaked through, insulation and lower drywall are common removals. Solid wood, masonry and sealed surfaces are often kept when they dry to readings and are clean.

The test is the reading and the condition of the material. A piece of trim that is firm after drying can be kept. A piece of drywall that has swollen or lost its paper facing is removed. A subfloor that is soft is checked and replaced where needed.

The crew marks the boundary of each removal and records what was kept and why. You will be shown the list before anything is discarded, and you can ask questions about any item.

How is the structure dried to readings?

Air movers and dehumidifiers run until the framing, subfloor and wall cavities read dry at the points marked on the plan. Drying is measured, not timed, and it is judged by the readings rather than by how the surface looks.

Air movers push air across wet surfaces, and dehumidifiers pull moisture out of the air so the drying can continue. Both are needed in humid weather, and the setup is changed as the readings fall.

The end point is the dry reading for each material, measured in the same places as the first readings. The record is given to you so you can see where each area stood when the drying finished.

What should you watch for after the drying is done?

Check the floors and walls over the following weeks for new stains, a musty smell or soft spots. Moisture that returns usually means a source was missed or a material was left wet, and it is worth a call.

Walk the rooms and look at the baseboards, the lower walls and the floor near the doors. Note any change in colour, smell or feel, and take a dated photograph from the same spot as before.

Check the grading, the gutters and the downspouts after each heavy rain. Water that runs back toward the house can bring the problem back, and correcting it is work for a contractor you choose.

What about the garage, the car and the stored items?

A garage or shed that takes water under its door needs the same steps as a room: extraction, removal of soaked material and drying. Stored items on the floor, boxes and cardboard are usually lost to water, and anything stored high is checked before it is reused.

Garages often have a slab that floods at the door and a wall base that wicks water up. The crew extracts the water, checks the slab edge and dries the wall base, which is where the moisture stays longest. A vehicle that has been in water needs its own check, and that is outside the building work.

Keep a list of what was stored in the garage or shed, with photographs taken before anything is moved. Boxes, paper and cardboard that were wet are normally discarded, and metal, tools and sealed goods can often be cleaned and kept after a check.

How can you reduce the chance of the next flood entry?

Check the grading, the gutters and the downspouts, and make sure water leaves the house rather than pooling against it. Seal visible gaps at doors and vents where the crew found water, and keep the crawl space vents clear. Corrections to grading and drainage are made by a contractor you choose.

Water runs to the lowest point, so the ground around the house matters as much as the walls. A slope that drains toward the foundation, a downspout that discharges at the wall or a gutter that overflows will each send water to the place it is most likely to enter.

The crew can point out the entry points it found, and you can ask for those to be recorded in the file. The fix is set by the contractor you choose for grading or drainage, and the water work does not include that repair.

How long before the house can be lived in normally?

The house can be used again once the affected rooms read dry, the air is back at a normal humidity and the crew has closed the work with a written record. The schedule depends on how deep the water went and how much material was removed.

Rooms that were not wet can often be used sooner, but the air from the drying area should be kept out of them. Keep doors to the wet rooms closed, and ask the crew which routes are safe to walk and which are off limits while the equipment runs.

Living normally does not mean the work is finished. The rebuild, the new flooring and the final paint follow the drying, and each should wait for the readings to confirm the structure is dry. Ask the crew for the final readings before the trades start.