Advice on drying out historic buildings

The following information arrives courtesy of the Preservation Society of Asheville & Buncombe County and the State Historic Preservation Office: 

1. Prioritize Safety Precautions
Before beginning any restoration efforts, ensure your safety and that of others.
Assume power lines are live, turn off electricity, and check for gas leaks. Be
cautious of contaminated floodwaters, wear protective gear, and consult
professionals if uncertain about safety.

2. Make a Plan
Take time to plan. While it is tempting to wade right in with a shovel and mop, it is
very important to develop a plan for cleanup and restoration. Unfortunately,
overly zealous cleanup efforts can result in salvageable materials being carted
away, excessively rough cleaning methods, and the unnecessary loss of historic
fabric. The best way to prevent additional damage to historic structures and
materials during a time of duress is to use caution, move slowly, and plan ahead.

3. Document Damage
Capture the extent of damage through photographs before cleanup. Take
photographs and video of the interiors and exteriors of the building, as well as
equipment and personal property. These records are valuable for insurance
claims and negotiations. Be sure to capture damage to:

 Interior, exterior windows and doors
 Roofs
 Electrical, plumping, gas, water supply, sewer, and septic systems
 Floors, ceilings, and walls (include cracks and signs of sagging)
 Foundations
 Nearby sidewalks
 Landscaping (such as fallen trees)
 Furniture, appliances, office equipment, vehicles, and other objects (take
photos of the serial numbers of large appliances and equipment while
documenting damage)

4. Prevent Further Water Entry
Temporarily repair roofs and windows to prevent more water from entering. Plan
these fixes to last at least six months. Options include tarps, felt paper, or
plywood covered with building wrap.

5. Remove Waterlogged Materials as Quickly as Possible
Remove furniture, wet carpets, sheet vinyl, linoleum flooring, and LVP/LVT as
they will retain moisture in the building.

6. Address Ceiling and Wall Damage
Inspect ceilings and walls for hazards and trapped water. Drain ceiling and wall
cavities and increase airflow within the walls and ceilings by creating small
openings and temporarily removing baseboard. Remove any and all wet
insulation. Approach wet plaster and wet sheetrock differently. Seek to retain and
repair plaster with plaster washers and use temporary shoring for ceilings.
Remove wet sheetrock in sections corresponding to its 4×8 feet sheet size. If
exposed to floodwater for less than two hours, sheetrock can usually be
salvaged. Beyond that, replacement is most likely necessary.

7. Increase Ventilation
The least damaging drying process begins by using only ventilation. The most
effective way to do this is to open windows and doors and allow the moisture to
escape. Remember, controlled drying and unencumbered ventilation is key.
Avoid rushing the process with heaters or air conditioners, as this can cause
additional damage to building elements. Allow for gradual drying to maintain
structural integrity. You can also run dehumidifiers to reduce humidity.

8. Remove Mud
Rinse mud, dirt, and flood debris with fresh water as soon as possible—it is safer
and easier to remove the mud while it is still wet. Avoid using high pressure water
on historic materials and exercise extreme care, so as not to cause further
damage.

9. Beware of a Flooded Basement
Water in the basement should not be drained too quickly, the pressure outside of
the walls will be greater than the pressure inside the walls, which may lead to
cracking and collapse. Be careful when pumping water out of your basement. If
the water level is high, and you are reasonably sure your drains are working,
groundwater levels may also be high and pumping water out could result in either
more water coming in or a foundation collapse. It is generally advisable to wait
for high water to recede on its own. If you do have to pump water out of the
basement, it is recommended only to pump down 2-3 feet per day.

10.  Address Ductwork and Other Building Systems
Clean standing water in ductwork with fresh water and remove electrical devices
(receptacle outlets, switches) if submerged.

11. Restore Wood Floors
Wash mud off wood floors with water. Avoid rapid drying methods like forced air
conditioning or heat, which can cause warping. Use weights to prevent severe
warping and ensure air circulation underneath the floor if possible.

12.  Clean and Restore Interior Features
Clean wood features like trim, mantles, and other woodwork with disinfectants
and remove mud and silt. Mold and mildew can be treated with a diluted Clorox
solution. Save removed features for reinstallation.

13. Treat Household Furnishings
Properly handle water-damaged furnishings, including textiles, books,
photographs, and furniture. See FEMA guidance on salvaging historic and
heirloom objects and consult an objects conservator if necessary.

14. Remove Mold
Mold remediation is a serious issue after floods and storms as it can have
extreme health impacts on early responders. Mold can easily grow in wet
buildings and structures, and can also contaminate special collections, business
inventories, and supplies.