Dear Friends of the National Trust:
 
In response to the devastating flooding that the region is experiencing, the National Trust would like to share some resources to ensure that the floods do not become a double tragedy for our region's rich built heritage.  To avoid losing more historic properties than necessary, we wanted to share the materials and some experience the National Trust has gained from our 6 months of hurricane relief work in New Orleans and the Gulf Coast, as well as prior natural disasters over the past 15 years.   If you are not impacted by the flooding but know someone who might benefit from this information, we ask that you please forward it.
 
While floodwaters can cause significant damage to historic buildings, they do not spell the end.  Many of these buildings have stood the test of time and have survived previous devastating floods.  With proper cleaning and drying out procedures, the only reminder of floodwaters in historic structures should be a watermark and date on the wall.

After a building has been saturated, once the floodwaters recede and it is safe to return, it is important that the drying process begin immediately. Most of the damaging effects of water, such as rot, rust, and spalling, can be minimized by reducing both interior and exterior moisture levels.  The least damaging method for drying out a building is natural ventilation--open the doors and windows, and if safe,  also use dehumidifiers and fans.  Although tempting, do not use heat!  Warm, moist environments encourage mold and fungal growth.

Use caution when pumping water from basements.  This water may be providing the necessary pressure to balance the hydrostatic pressure of the groundwater. If the groundwater level is higher than your basement floor and you pump the water from your basement, the foundation walls could be pushed inward and collapse.  If your basement is flooded with several feet of water and you are reasonably certain that your floor drains are operational, you can assume that the groundwater table is high. It is advisable to leave the water in place until the groundwater table sinks and the water recedes by itself. If your basement contains only a few inches of water, however, you may be able to pump it out safely. Keep in mind that if the groundwater level is higher than the floor, the water will return.  Even if you cannot pump the water out of the basement, consult with local health officials to determine if there is any sanitizing agent that can be used to treat standing water in the basement.

A checklist and much more detailed information is available in the booklet, "Treatment of Flood-Damaged Older and Historic Buildings," available online as a PDF at http://www.nationaltrust.org/hurricane/files/flood_booklet.pdf.  For an updated version of the booklet, it can be ordered free of charge at http://www.preservationbooks.org/showBook.asp?key=109
 
Additional flood-related resources and funding sources from the National Trust, FEMA, and other organizations can be found at:  http://www.nationaltrust.org/hurricane/resources.html
   
The National Park Service has a series of helpful briefs on a wide range of topics related to repairing historic structures available to view and print free of charge at http://www.cr.nps.gov/hps/tps/publications.htm
 
It may be important, to avoid buildings being condemned or demolished needlessly, that preservation advocates make sure that people knowledgeable in the preservation of older buildings be tapped to conduct building assessments.   A list of preservation consultants who work in the region can be found at http://www.preservationmass.org/consultants.shtml.  Some additional preservation tradespeople are listed at http://www.preservationworks.org/pei%20directory.htm.   Contact your state historic preservation office and statewide preservation organization for other referrals.   

If the National Trust's Northeast Office can be of further assistance,  please don't hesitate to contact them at (617) 523-0885 or nero@nthp.org