Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
WATER ENTRY in BUILDINGS
AGE of MOLD, HOW OLD
BASEMENT CEILING VAPOR BARRIER
BASEMENT MOLD WATER IMPACT
BRICK WALL DRAINAGE WEEP HOLES
BUCKLED FOUNDATIONS due to INSULATION?
BUILDING DAMAGE ASSESSMENT & REPAIR
CONDENSATION on WINDOWS & SKYLIGHTS
DEW POINT TABLE - CONDENSATION POINT GUIDE
EFFLORESCENCE SALTS & WHITE DEPOSITS
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOOD DAMAGED FOUNDATIONS
FLOOD VENTS & FLOOD PORTS
FLOODS in BUILDINGS, MOLD PREVENTION
FLOOR DAMAGE DIAGNOSIS
FOOTING & FOUNDATION DRAINS
FOUNDATION BULGE or LEAN MEASUREMENTS
FOUNDATION CRACKS & DAMAGE GUIDE
FREEZE-PROOF A BUILDING
FROST HEAVES, FOUNDATION, SLAB
GOPHER HOLE DAMAGE
HUMIDITY LEVEL TARGET
ROOF ICE DAM LEAKS
MOISTURE CONTROL in BUILDINGS
MOLD INFORMATION CENTER
NOISE / SOUND DIAGNOSIS & CURE
ODORS GASES SMELLS, DIAGNOSIS & CURE
SEWAGE BACKUP, WHAT TO DO
SEWAGE BACKUP TEST & CLEANUP
SEWAGE BACKUP PREVENTION
SEWAGE PUMP CLOG DAMAGE
STAIN DIAGNOSIS on BUILDING EXTERIORS
STAIN DIAGNOSIS on BUILDING INTERIORS
SWEATING (CONDENSATION) on PIPES, TANKS
TOILETS, INSPECT, INSTALL, REPAIR
TRAPS on PLUMBING FIXTURES
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VENTILATION in BUILDINGS
WATER ENTRY in BUILDINGS
WINTERIZE A BUILDING
How to re-build a water, storm or flood damaged building and how to include measures that reduce the chances of future water or storm damage. Earthquake, hurricane, flood or storm & wind damage to buildings: action & repair priorities: If your building has been flooded, this article series provides a guide for flood damage assessment, priorities of action, safety,cleanup, repair, restoring utility systems, and rebuilding.
We include information on avoiding or minimizing mold damage. Adapted and expanded from Repairing your Flooded Home, American Red Cross & FEMA & from additional expert sources. NOTICE: neither the ARC nor FEMA have yet approved the additions & expansions we have made to the original document.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
However this reasonable advice from FEMA/ARC faces some stumbling blocks expressed by building managers & developers of costly high-rise and other large buildings in the Northeastern U.S. following extensive flooding caused by Hurricane Sandy in 2012.
While we do not completely agree with them, comments and opinions reported by the New York Times (January 2013) included the following: 
We don't agree with these views because we suspect that climate trends mean that the frequency of severe weather and flooding continues to increase as a consequence of global warming, and because the total osts of flood and storm damage in lost occupancy, building repairs, and possibly human costs, will continue to exceed the optimistic hopes of some building managers. We do agree with another concern reported by the Times, that current building codes and their treatment of basement or upper floor spaces used for mechanical systems need revision to address building use and valuation concerns expressed by developers and owners.
Floodproofing Approaches to Towns, Villages, Homes
In February 2013 the New York Times reported on a remarkable plan by Highlands, New Jersey to raise the entire town by eight to ten feet above its present level. The town, just about at sea level, is thus located in a designated Flood Zone V - the highest flood risk designation in FEMA's flood zone maps. Of course, Highlands has still to convince federal funding sources to pvovide its share of the $25. million that will be needed for the project. The Highlands mayor and others recognized that left unchanged the town would simply continue to flood. The Times article explained the strategy for Highlands: a series of canals could ease the import of sand fill brought in to increase the elevation of the town as building by building, structures would be raised throughout the downtown area: a space about 1500 feet by a mile in length and involving about 2000 buildings to be elevated in sections, 1/4 sq.mi. at a time.. 
Choices facing a town at sea level include several options, but the viability of individual options will vary considerably from one locale to another:
Questions to Ask Before Rebuilding a Flood-Damaged Building
Should you rebuild at all? If the building is located in an area likely to be constantly flooded and damaged it may be that relocation is a better course of action.
If you are going to rebuild the flood-damaged structure in its present location, before you repair or rebuild, the first thing you should do is talk to your town’s or city’s or county’s building department. You will need to ask the following questions:
Five Types of Floodproofing
1. Elevation of the building or of key building mechanical systems as a means of preventing future flood damage
Building Elevation for Flood Damage Resistance
Elevation of Building Mechanical Systems for Flood Damage Resistance
In January 2013 and following the widespread damage occurring in 2012 due to Hurricane Sandy in New York, Julie Satow reported in the New York Times that in buildings located close to water boundaries ( the Ocean or the Hudson River, for excample) building developers and architects began an increased emphasis in combining building waterproofing measures with steps to raise mechanical systems out of basements and onto upper building levels. 
Backup generators in larger and public buildings, even excluding special requirements (such as for hospitals operating life-maintaining equipment) need to be able to handle the electrical demands of :
Backup electrical systems in new construction or in buildings undergoing extensive renovations may include distribution of at least one backup-powered electrical ciruit to each building apartment or room
By placing mechanical systems as well as emergency generators (GENERATORS, BACKUP ELECTRIC) on higher building floors, even rooftops, it may be possible to keep some buildings open during severe weather or flood conditions.
2. Relocation of the Building as a means of preventing future flood damage
3. Floodwall construction & use of Flood Gates as a means of preventing future flood damage
In 2013 the New York Times described developers' addition of portable five-foot tall floodgate assemblies that can be stored until needed, then assembled and installed to encircle the building "in a matter of hours". Other flood-gate designs extend in height as much as 13 ft. above grade. .
4. Dry floodproofing as a means of preventing future flood damage
Sump & Pump Systems for Flood Damage Minimization
In a building that will rely on pumping systems to keep water out of basements or low areas,
5. Wet floodproofing as a means of preventing future flood damage
The New York Times article cited above  also described installation of "floodgates and submarine-style [water-tight] basement doors" to control water entry into the basements of high-rise buildings. Allowing water to enter a building basement during periods of area flooding tends to equalize pressures on both sides of the building foundation, reducing the chances of potentially catastrophic foundation collapse. See FLOOD VENTS & FLOOD PORTS for steps used to protect smaller and residential buildings from foundation damage due to flooding.
In a companion approach to minimizing the damage and costs of building flooding, building designers convert the use of basement and even flood-prone fdirst floors of buildings whose structures can withstand the forces of floodwaters. Using a building basement as a parking garage rather than as the home to building mechanicals or occupied spaces substantially eliminates the presence of materials and mechanical systems that will be damaged or more-likely destroyed by flooding.
For flood-prone building levels that will remain in use as occupied spaces, the original FEMA/ARC flood damage prevention article suggested:
Building permit requirements when rebuilding a damaged building
Rebuilding tips for Wet Basements or Flooded Homes
Better advice for drying out a flooded building adds these tips:
Make sure that all demolition and removal of soaked materials that cannot be salvaged (such as drywall, carpets, upholstered furniture) are removed as quickly as possible. Standard advice to avoid a mold contamination issue is that a building must be dried within 24-48 hours of being soaked - a recommendation that may be impossible when floodwaters inundate a large area. If weather temperatures are cold, in the 40's F or below, you may gain additional time as cold temperatures tend to slow the growth of mold in building materials.
When it is possible to enter a building safely to complete demolition, initial dryout and cleaning, do not simply rely on time to adquately dry the building. When electrical power can be used safely, and when weather permits, the addition of fans to increase air circulation, portable heaters and dehumidifiers can significantly speed the dryout process.
Do not leave trim or soaked drywall in place; remove those items to expose wood structural components to air circulation. Review Step 4. BUILDING DRY-OUT PROCEDURES for details.
Flood Damage Insurance Payout May be Limited
Watch out: when deciding to restore & rebuild a basement-level apartment (also referred to as "garden apartments") be aware that flood insurance policies for below-grade-level spaces in buildings cover only damage to the mechanical systems (boilers, water heaters, electrical panels). Details are at Flood Damage Insurance Payout May be Limited for Basement Apartments discussed in Step 7. Check on Financial Assistance
Following Hurricane Sandy in 2012, by January 2013 The New York Times reported that in some areas such as Hoboken NJ, in order to even attempt to obtain financial aid and despite buildings being covered by required flood insurance under NFIP, owners of basement-level or garden apartments must apply for grants to receive a portion of storm damage aid approved by the U.S. Congress. Further, even if some grants are approved the levels will not be sufficient to cover the total costs of cleaning and repairs to these flooded dwelling areas.
Use Products that resist water damage
Choose structural and furnishing materials that are more resistant to water damage and to absorbing sewage-contaminted waters during times of flooding:
Advice for Floodproofing Building Utilities & Mechanical Systems
Relocate Mechanical Systems & Electrical Components to resist future water or flood damage
Keeping a building open in times of storms, hurricanes and flooding will require much more than just providing emergency heat, fire alarms, or even a reservoir of water.
During flooding and often for some period afterwards, public sewers and private septic systems are not serviceable and may require pumping and mud or silt removal before those systerms can be returned to operation. Heat and electrical service will require additional steps to assure safe operation and a safe, functional fuel supply. Air conditioning systems may be inoperable even if the equipment itself is above floodwaters if ducts have been flooded.
Protect Electrical Panels & Switch Gear from Flooding
Watch out: for basic safety, ask your electrician to review the building electrical ground system to assure that in wet conditions the connection between the electrical panel and your local electrical ground will remain intact. If the building is not safelyi and properly grounded in wet conditions, keeping electrical power on risks shock or death by electrocution.
Moving electrical panels to higher building levels may not be enough to assure safe funcational use of backup electgrical generators and emergency electrical circuits in a building if the isolation switch or other key switch gear are not also located above possible flood levels. The New York Times article cited above  reported that during & following Hurricane Sandy in New York, although a rental building had its boiler and generator located on the building roof, the switching gear (presumably the isolation switch used to disconnect the building from the public electrical utility lines and to connect its emergency circuits to the backup generator system) were located in the flooded basement. Building management cited both relocation cost and concern for loss of lucrative lower level spaces as issues in relocaing the switch gear.
FEMA/ARC advice continues:
Provide fuel for emergency generators & heating systems in a floodproofed building
Warch out: unless the fuel supply for your heating equipment is also protected from flooding by location and type of fuel source you will not be able to use heating equipment even if it has itself been protected from flooding. For this reason some building designers installing emergency generators select a generator that can operate from LP gas, placing the LP fuel tank on the building rooftop or in another elevated location, and protecting the fuel lines from flood damage not only from submersion in water, but from impact by storm-driven debris.
Protect fuel storage tanks from water entry and movement
Diesel fuel, Heating Oil or LP gas storage tanks used to store fuel used for backup generators or building heating equpiment are at risk of movement, mechanical damage, and water entry during flooding. See
Isolate Flooded HVAC ducts to provide heating or air conditioning in a floodproofed building
You may be able to provide air conditioning to some building areas even if lower floors have been flooded if the duct design permits manual or automatic zone dampers to cordon off and deactivate supply and return ducts that have been flooded. Failure to isolate HVAC ducts that have been flooded, or return air ducts that might draw air from flooded areas risks mold contamination of the entire HVAC system and can present serious health risks to building occupants if the system circulates mold or sewage pathogens throughout occupied spaces.
Wall reconstruction for a wet basement or flooded building
Wallboard installation pattern to resist future water damage
1” gap between floor and drywall bottom edge
Floor reconstruction material choices for a wet basement or flooded building
Painting details for finishing a previously wet basement or flooded building
Generally, "completely dry" means that moisture levels in the building material to be painted should be well below 18%, 12% or lower is better. When using a moisture meter to check moisture levels be sure to check areas most likely to remain damp, such as lower on walls, close to floor level, areas more distant from points of ventilation such as windows or doors, and at intersections of walls/floors and walls/ceilings.
Products to Avoid Avoid using or storing in areas likely to flood
How to Work With a Contractor for Reconstruction of a Building after Wetting or Flood Damage
Continue reading at FLOOD REPAIR CONTRACTORS - separate article describing how to work with contractors & insurance companies after building damage by a disaster or flood, what the contractor should do, and how to resolve disagreements.
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs)
No FAQs have been posted for this page. Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Questions & answers or comments about rebuilding and floodproofing a building after a flood or other disaster.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References