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Got Flood?

Being informed and aware of all national and local regulations is the best way to protect your property and to fall into compliance. This is an extremely important site specific issue that requires a professional surveyor, potentially advice from your local flood plain manager, your insurance agent and a real understanding of the costs of restoration to a damaged structure. Mistakes made immediately after a loss can become very expensive as elevating a slab on grade house is many times not cost effective especially with a cap of $30,000 for code on the Flood Insurance Program.

Things to Consider When Reviewing Flood Insurance Requirements. Flood Insurance Rate Map


Pre-FIRM Building – A building for which construction or substantial improvement occurred on or before December 31, 1974, or before the effective date of an initial Flood Insurance Rate Map(FIRM). Pre-FIRM structures receive a subsidized rate because they were built before floodplain management standards were established .If a better rate can be obtained for flood insurance coverage, a Pre-FIRM structure can be rated as Post-FIRM. The better rate would be obtained by providing a FEMA Elevation Certificate signed and sealed by a registered professional engineer or land surveyor showing that lowest floor of the structure is “At or Above” the Base Flood Elevation (BFE) at that location. The elevation certificate will allow Post-FIRM rating; it will not remove the mandatory purchase requirement for flood insurance required by the lender. To remove the mandatory purchase requirement, see LOMA and LOMR-F below.


Post-FIRM building – A building for which construction or substantial improvement occurred after December 31, 1974, or on or after the effective date of an initial Flood Insurance Rate Map(FIRM), whichever is later.

Post-FIRM buildings

The rules do not address only pre-FIRM buildings — they cover all buildings, post-FIRM ones included. In most cases, a post-FIRM building will be properly elevated or otherwise compliant with regulations for new construction. However, sometimes a map change results in a higher BFE or change in FIRM zone. A substantial improvement to a post-FIRM building may require that the building be elevated to protect it from the new, higher, regulatory BFE.

It should be remembered that all additions to a post-FIRM building must be elevated at least as high as the BFE in effect when the building was built. (You can’t allow a compliant building to become noncompliant by allowing additions at grade.) If a new, higher BFE has been adopted since the building was built, additions that are substantial improvements must be elevated to the new BFE.

What is Substantial Improvement, Substantial Damage, or the “50% Rule”?
The National Flood Insurance Program require buildings within the Special Flood Hazard Area that are improved at a cost which is 50% or more of the existing building’s market value before the improvement is started to meet current construction standards for buildings in a floodplain. The value of the structure is the estimate before the “start of construction” of the improvement. This term includes structures which have incurred “substantial damage,” regardless of the actual repair work performed. The term does not, however, include either:

Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions; or

Any alterations of a “historic structure,” provided that the alteration will not preclude the structure’s continued designation as a “historic structure.

The FEMA substantial damage rule should not be confused with the “Repairs to Existing Buildings” code called for in the International Building Code. This often happens and can be very confusing.


The cost of the project exceeds 50 percent of the building’s value, so it is a substantial improvement. The loodplain regulations for new construction apply and the building must meet the post-FIRM construction requirements. If the project is an addition, only the addition has to be elevated.

The formula is based on the cost of the project and the value of the building. These two numbers must be reviewed in detail.

Project cost

The cost of the project means all structural costs, including

• All materials
• labor
• built-in appliances
• overhead
• profit
• Repairs made to damaged parts of the building worked on at the same time

When buildings undergo repair or improvement, it is an opportunity for local floodplain management programs to reduce flood damage to existing structures. More than 21,000 communities participate in the National Flood Insurance Program (NFIP), which is managed by the Federal Emergency Management Agency (FEMA). To participate in the NFIP, communities must adopt and enforce regulations and codes that apply to new development in Special Flood Hazard Areas (SFHAs). Local floodplain management regulations and codes contain minimum NFIP requirements that apply not only to new structures, but also to existing structures which are “substantially improved (SI)” or “substantially damaged (SD).” Enforcing the SI/SD requirements is a very important part of a community’s floodplain management responsibilities. There are many factors that local officials will need to consider and several scenarios they may encounter while implementing the SI/SD requirements.