After a coastal flood and when retrofit work is about to begin, it will be necessary to determine the readiness of insulated assemblies for spray foam insulation. It is most desirable that surfaces be clean and dry to accept spray foam. Wood should have a moisture content of less than 19%. Concrete should be visibly dry and free of residue. Metals should be free of dirt and oil. Any surfaces subjected to flooding should be disinfected and treated to address mold. Residual salt should not impact spray foam.
It is often advisable that spray foam be ‘test-sprayed’ to determine if it will bond to treated lumber, sheathings and other materials where an interaction is possible. Based on the test spray, it may be necessary to clean or prime surfaces to accept a coating of spray foam.
Retrofit work will often involve raising older buildings and constructing new buildings on piers or platforms above the Base Flood Elevation (BFE) and ensuring that construction below the BFE be done with flood-resistant materials.
As previously mentioned, FEMA recognizes closed cell spray foam as flood-resistant and suitable below the BFE. It may not be necessary to insulate with flood resistant materials if such portions of the building are non permanent and it may be desirable to insulate with materials than can be easily removed if required (e.g. soft, open cell foam).
Above the BFE both open cell and closed cell foams can be used. The choice of materials should be made based on sound building science principles. For instance, in a floor above a damp crawlspace it may be desirable to use closed cell spray foam because of its vapor retarding characteristics. Some designers of floor assemblies that may have occasional flooding above the floor surface, prefer to install open cell foam so that the water from above can drain through the foam keeping the plywood subfloor drier after the flood waters recede. An Icynene Certified Dealer can assist in identifying the right product for the right application.
Download a complete White Paper on hurricane remediation here. Understand more about how spray foam insulation aids remediation efforts here.