Disaster Preparedness and Recovery

Cleaning Up Flood-damaged Walls

Walls must be dry from the inside out before restoration, repainting, or recovering can begin. Even when walls feel dry to the touch, the material inside the wall may be wet. Drying the inside of the walls may take weeks or even months. The total drying time will depend partially on the amount of dry air that can circulate through the studding and different wall materials.

Wallboard soaked by dirty floodwater will need to be replaced.

Remove drywall, laminated paneling, and plaster at least to the flood level. Because warping above the water level often occurs with drywall and paneling, more may need to be removed.

Plaster and paneling can often be saved, but you still need to get air circulating in the wall cavities to dry the studs and sills.

Plaster walls can sometimes be drained adequately by removing the baseboard and breaking out plaster and lath at the bottom of the wall. Later the baseboard can cover the opening.

Do not attempt to repair plaster until walls and inner walls (studding and insulation) are completely dry. If walls were flooded extensively, you may need to wait four to six weeks, or even several months, before attempting repairs.

Drywall compound is the preferred method for patching plaster. It comes in a variety of types with different drying times, shrinkage characteristics, and consistencies. Read labels to select the type you need.

Some paneling may be salvaged if allowed to dry slowly. Remove the baseboard from paneled walls and pry off the individual sheets. Prop them against the wall to dry. Don’t allow them to dry in sunlight, which may cause warping.

Remove vinyl-covered wallpaper. It will restrict drying within flood-damaged walls.

Water-soaked insulation should be removed and replaced. It can hold water for months, causing odor and decay problems. While wet, it has little insulation value.

Remove a small section of siding to check conditions on the reverse side. If crevasses are filled with silt, remove siding to water level and clean. Silt left in crevasses will trap moisture, causing mold, decay, and peeling paint.

Check for cracked or warped siding. If only a few boards are warped or cracked, replace them individually.

Sheathing is the material between studding and finish siding. Depending upon the type of sheathing, replacement may be necessary.

Wooden boards should dry slowly. Some will warp. Re-nail warped areas after they dry. Replace those that are too badly warped to salvage.

Sheathing board is usually absorbent and difficult to dry. Replace any that is disintegrating or separating.

Plywood probably will separate and need to be replaced. Marine plywood will not warp or separate, but it is generally considered too expensive to use in residential construction unless the building is subject to frequent flooding.

Adapted from the resource material developed by the University of Wisconsin-Extension Service entitled “The Disaster Handbook for Extension Agents”

WVU Extension Service Disaster and Emergency Management Resources
Cleaning Up Flood-damaged Walls
Section 13.3 Page 2