ADD WATERPROOF VENEER TO EXTERIOR WALLS
Protecting Your Property from Flooding
FEMA
April 2008

Even in areas where flood waters are less than 2 feet deep, a 
structure can be severely damaged if water reaches the interior. The 
damage to walls and floors can be expensive to repair, and the 
structure may be uninhabitable while repairs are underway. 

One way to protect your property from shallow flooding is to add a 
waterproof veneer to the exterior walls and seal all openings, 
including doors, to prevent the entry of water. As shown in the 
figure, the veneer can consist of a layer of brick backed by a 
waterproof membrane. Before the veneer is applied, the siding is 
removed and replaced with exterior grade plywood sheathing. If 
necessary, the existing foundation footing is extended to support 
the brick. Because the wall may be exposed to flood water, changes 
are also made to the interior walls to resist moisture damage. In 
the area below the flood level, standard batt insulation is replaced 
with washable closed-cell foam insulation, and any wood blocking 
added inside the wall cavity is made of exterior grade lumber. 

BENEFITS OF UTILIZING THIS MITIGATION STRATEGY

* Helps to prevent flood water from entering a building, which could 
result in the structure being uninhabitable while undergoing repairs

TIPS 

Keep these points in mind if you plan to have a waterproof veneer 
added to the exterior walls: 

* Adding a waterproof veneer is appropriate in areas where the flood 
depth is less than 2 feet. When flood depths exceed 2 feet, the 
pressure on waterproofed walls increases greatly, usually beyond the 
strength of the walls. If greater flood depths are expected, consult 
with a licensed civil or structural engineer before using this 
method.  

* Changes to the foundation must be done by a licensed contractor, 
who will ensure that the work is done correctly and according to all 
applicable codes. This is important for your safety.  

* If your property is being remodeled or repaired, consider having 
the veneer added as part of the remodeling or repair work. It will 
probably be less expensive to combine these projects than to have 
them done separately. 

* If your property has brick walls, you can still use this method. 
The new brick veneer and waterproof membrane are added over the 
existing brick. 

* If your property is flooded by groundwater entering through the 
floor, a waterproof veneer will not be effective. 

ESTIMATED COST 

If you have a contractor add a waterproof brick veneer, you can 
expect to pay about $10 per square foot of exterior wall. For 
example, a 3-foot high brick veneer on a structure measuring 60 feet 
by 30 feet would cover about 540 square feet and would cost 
approximately $5,400. This figure does not include the cost of 
sealing doors and other openings or extending the foundation. 

OTHER SOURCES OF INFORMATION 

FEMA 259, Engineering Principles and Practices for Retrofitting 
Flood Prone Residential Buildings, January 1995, 
http://www.fema.gov/library/viewRecord.do?id=1645. 

FEMA 549, Hurricane Katrina in the Gulf Coast: Mitigation Assessment 
Team Report, Building Performance Observations, Recommendations, and 
Technical Guidance, July 2006, 
http://www.fema.gov/library/viewRecord.do?id=1857. 

FEMA 549, Hurricane Katrina in the Gulf Coast: Mitigation Assessment 
Team Report, Building Performance Observations, Recommendations, and 
Technical Guidance, Recovery Advisory “Designing for Flood Levels 
Above the BFE,” July 2006, 
http://www.fema.gov/library/viewRecord.do?id=2633. 

To obtain copies of FEMA documents, call the FEMA Publications 
Warehouse at 1-800-480-2520 or visit FEMA’s Library online at 
http://www.fema.gov/library.