Page 647 - 2018 National Home Improvement

2018 National Home Improvement Estimator, All Rights Reserved Page 519

Dryout by Type of Material
How you restore saturated floors, ceilings and walls depends on the materials involved.

Wallboard. Ceilings and walls in most homes built after about 1950 are finished with gypsum wallboard.
"Gypboard" acts like a sponge, drawing moisture up the wall above flood level. Any mud or
contaminants in the floodwater will bond to the gypsum, making the wallboard a permanent health
hazard. Wallboard soaked in a flood usually has to be removed and discarded. If flooding hasn't soaked
more than the lower 2 or 3 feet of board, consider removing just the lower 4 feet of each panel. Toenail
2" x 4" wood blocks horizontally between the studs 4 feet above the floor. Then hang 4' x 8' sheets of
gypboard with the long edge horizontal, as in Figure 19-5.

Wallboard on interior walls that's been soaked with clean water will be worth saving if drying starts within
the first 48 hours. After that, gypboard deflects, gets fragile and will usually need to be replaced.

Stucco and plaster will survive a flood better than gypsum wallboard. You'll have to remove stucco or
plaster wall finish only if finish coats have separated from the lath below or if saturated insulation in the
wall has to be removed. Vapor barrier in the wall won't be damaged by flooding. If a plaster or stucco
wall is in good shape and doesn't include saturated insulation, follow the following instructions for
structural drying of stud cavities. Drying stucco or plaster is slow work, even with plenty of air drying
equipment.

Insulation. Flooded foam insulation board usually requires only a rinse down. Wet fiberglass batts
should be removed and discarded so the rest of the wall can dry. Once the wall is dry, install new batts.
Cellulose insulation will hold moisture for weeks. Even when dry, most of the antifungal and fire retardant
rating will be gone. Plan to replace saturated cellulose insulation.

Wood. Wood framing lumber in an existing home usually has a water content of about 10 percent.
Lumber that's been submerged can have a water content of 30 percent or more. The extra moisture
causes swelling which warps lumber out of shape. If allowed to dry, most wood framing will return to the
original condition. Wet studs and sills that swell out of shape won't need to be torn out. But wood
framing soaked in contaminated water will need to be treated before being covered with finish materials.

A moisture meter will be useful when drying wood, especially wood flooring. Most moisture meters have
two thin probes. Hold the probes against the material being tested to find the moisture content. Moisture
meters work on carpet, wallboard, wood, brick, and concrete.