Siding in a New Orleans Flood Zone: Elevation, the 50 Percent Rule and Coverage

Written by Turnkey Siding

This article is general information about floodplain rules and flood insurance in the New Orleans area. It isn’t legal or insurance advice. Your parish floodplain office and your policy documents control how the rules apply to your home.

What Does a New Orleans Flood Zone Mean for Siding Work?

Quick Answer: If your home sits in a Special Flood Hazard Area, a siding project can bring floodplain rules into play in two ways. First, the cost of a large job counts toward the 50 percent threshold for substantial improvement, and crossing it can require the whole building to meet current flood protection standards, which can mean elevation. Second, on new construction or a substantial improvement, materials used below the base flood elevation need to be flood damage-resistant under FEMA guidance. Look up your flood zone and your elevation certificate before you sign a contract, then call your parish floodplain office if the scope is large.

Most homeowners in New Orleans and Metairie think of flood zones as an insurance question, and homeowners in Chalmette tend to see it the same way. They’re also a building question. The flood map that comes up in insurance conversations also tells the permit office which floodplain rules your exterior work has to follow.

How Do You Find Your Flood Zone?

Start with FEMA’s Flood Map Service Center at msc.fema.gov, which the City of New Orleans points residents to for flood maps. Search your address and note the zone and base flood elevation shown for your property. Zones that begin with A or V are Special Flood Hazard Areas.

Then check what your parish offers:

• New Orleans: The Department of Safety and Permits keeps elevation certificates that have been submitted for review on file and makes them available to homeowners. Email floods@nola.gov with your property address to request one, or call (504) 658-7130.
• St. Tammany Parish: The parish links to LSU AgCenter flood maps you can search by address, and its floodplain administrator can answer questions about flood zone and flood history.
• Jefferson Parish: The parish has a Floodplain Management and Hazard Mitigation department. Ask it about the floodplain rules for your address.
• St. Bernard Parish: Call parish government and ask for the floodplain administrator before planning major exterior work in Chalmette or nearby.

Keep Your Elevation Certificate Handy

An elevation certificate shows how high your lowest floor sits compared with the base flood elevation. It matters for insurance, and it’s the first thing a floodplain reviewer will want to see on a large project. If your home is raised, our post on siding for raised and elevated homes in New Orleans covers how piers and skirting get detailed.

What Is the 50 Percent Rule?

The 50 percent rule comes from the National Flood Insurance Program regulations at 44 CFR 59.1, which define two terms:

• Substantial improvement means any reconstruction, rehabilitation, addition, or other improvement of a structure whose cost equals or exceeds 50 percent of the structure’s market value before the start of construction. The definition also includes buildings that have incurred substantial damage, regardless of the repair work actually performed.
• Substantial damage means damage of any origin where the cost of restoring the structure to its pre-damage condition would equal or exceed 50 percent of its market value before the damage occurred.

The City of New Orleans applies the same threshold. Its floodplain management page says a building that’s substantially damaged by any cause, or substantially improved, at 50 percent or more triggers flood protection requirements. St. Tammany Parish says all development in the floodplain requires a permit, including substantial improvement. When a project crosses the line, the building generally has to be brought into compliance with current floodplain standards, and for some homes that conversation turns to elevation.

Does New Siding Count Toward the 50 Percent?

Yes, under FEMA’s guidance. FEMA P-758, the Substantial Improvement/Substantial Damage Desk Reference, lists structural elements and exterior finishes among the costs that must be included, and it names brick, stucco, siding, painting, and trim as examples. A full re-side on its own may not come close to half your home’s value. Paired with a kitchen remodel or storm repairs, though, the total can climb faster than people expect, depending on how your community counts project costs.

Some Communities Count Improvements Over Time

FEMA P-758 also describes cumulative substantial improvement, an approach some communities elect to use, where improvement costs are tracked across multiple projects over a set period instead of one permit at a time. Ask your floodplain office whether your community tracks improvements this way and over how many years. It can change whether a siding job this year and an addition two years from now get added together.

What Is Freeboard, and Why Does It Matter?

Freeboard is extra height above the base flood elevation that a local ordinance can require as a safety factor. When a substantially improved home has to meet current standards, the required height for the lowest floor may be the base flood elevation plus freeboard, not the base flood elevation alone. Jefferson Parish’s flood ordinance, for example, sets freeboard for residential structures in AE zones, and the requirement differs inside and outside the Hurricane and Storm Damage Risk Reduction System. Requirements change, so get the current figure for your address directly from your parish floodplain office.

Which Siding Materials Hold Up Below the Flood Elevation?

FEMA’s Technical Bulletin 2, Flood Damage-Resistant Materials Requirements, was updated in January 2025. It covers the NFIP requirement that, for new construction and substantial improvements, building materials below the base flood elevation in Special Flood Hazard Areas be flood damage-resistant. The 2025 edition replaced the old five-class system with two ratings: acceptable and unacceptable.

For materials commonly used in walls, Table 1 of the bulletin rates brick as acceptable, and it gives cement board or fiber-cement board the same rating. It rates solid, standard wood used as finish or trim as unacceptable. FEMA adds two cautions worth repeating. A material’s listing isn’t a precise prediction of how it will perform when inundated or hit by debris, and manufacturers’ installation instructions have to be followed.

That’s one reason to look at fiber cement siding and brick for lower walls in flood-prone neighborhoods. We compare materials in more depth, including a section on flood zones, in our guide to the best siding materials for Louisiana homes.

How the Rules Play Out Across the Metro

The federal definitions set the floor for communities in the National Flood Insurance Program. How each parish administers them is where the local differences show up.

Orleans Parish

New Orleans runs floodplain review through the Department of Safety and Permits, and the floodplain administrator’s office is at 1340 Poydras Street, Suite 800. The city also has a Hazard Mitigation Office. If you’re thinking about elevation, ask that office whether any mitigation funding is currently open before you commit to a scope, since availability changes.

Jefferson Parish

Ask Jefferson Parish’s Floodplain Management and Hazard Mitigation department about freeboard and cumulative counting, or your city hall if you live inside a city such as Kenner or Gretna. Our siding permit guide for New Orleans and Jefferson Parish covers the general permit side of a re-side.

St. Tammany Parish

St. Tammany’s rule is short and clear: all development in the floodplain needs a permit. The parish warns that people who violate permit requirements may face penalties and may have to return the land to its prior state at their own cost. On the Northshore, including Slidell, call before work starts.

St. Bernard Parish

In Chalmette and the rest of St. Bernard Parish, confirm the floodplain review process with the parish before scheduling a large project, and have your elevation certificate ready when you call.

What Does Flood Insurance Have to Do With a Siding Project?

The Louisiana Department of Insurance notes that homeowners policies don’t cover flood damage, so flood coverage comes through a separate policy, often from the National Flood Insurance Program. LDI’s consumer guide also points out that a new flood policy may take 30 days to go into effect, and that NFIP coverage tops out at $250,000 for the house and $100,000 for contents.

If flood damage leads your community to declare your home substantially damaged, FEMA’s Increased Cost of Compliance coverage can pay up to $30,000 toward bringing the building into compliance, for example by elevating or relocating it. It applies to NFIP policyholders whose community determines the home is substantially or repetitively damaged by flooding. Eligibility and payment depend on your policy and the determination, so talk with your flood insurance agent. For the claim process after a storm, see our guide to filing a siding insurance claim in Louisiana.

How We Plan Siding Work on a Flood Zone Home

On a home in a mapped flood zone, we recommend pulling the flood zone and elevation certificate before anyone writes the scope. If the job is large, or it’s being paired with other renovation work, we suggest you check with the floodplain office early so the plan doesn’t have to change after tear-off. Ask for an estimate that separates repair costs from upgrades, since that makes any review easier, and choose lower-wall materials with FEMA’s flood damage-resistance ratings in mind.

Frequently Asked Questions

Does replacing siding count as substantial improvement?

The cost can count toward it. FEMA’s desk reference lists siding among exterior finish costs that must be included, and your floodplain office decides whether the total crosses 50 percent of market value.

Will re-siding my house force me to elevate it?

A re-side alone may not cross the threshold. It depends on how the total project cost compares with your home’s market value, and on how your community counts improvements. Ask your floodplain administrator before committing to a large scope.

How do I get my elevation certificate in New Orleans?

The city keeps submitted elevation certificates on file. Email floods@nola.gov with your property address.

What siding is best below the base flood elevation?

FEMA’s Technical Bulletin 2 rates brick and fiber-cement board as acceptable flood damage-resistant materials, and standard wood finish and trim as unacceptable. Your local code and floodplain office have the final say.

Plan Your Siding Project With the Flood Map in Mind

If your home is in a flood zone and the siding is due, we’ll walk the house and scope the work so there are fewer surprises at permit time. See our service areas or call 504-882-9704 for a free estimate.