Mold Guides · Room-Specific & Commercial Mold

Mold in Historic New Orleans Homes: What to Look For

A historic home in New Orleans is a beautiful thing, and it is also a building that carries its history in its walls. Old plaster, old wood, old plumbing, and a past that may include flooding, storms and repairs done in different eras by different hands. Those layers of history are part of what makes the home special, and they are also part of what makes it vulnerable to mold, because an older home has more places for water to get in, and more places for it to hide.

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This guide covers the factors to look for in a historic New Orleans home: old materials, past flooding, and ventilation, and the inspection-first guidance that follows. Our mold inspection and testing page covers the first step, and homes in New Orleans carry the same history.

Old materials and old construction

Historic homes are built with materials and methods that are different from modern construction, and those differences affect how moisture behaves in the building. Plaster walls absorb moisture and hold it, and they can hide growth behind a surface that looks sound. Old wood, in the framing, the floors and the windows, can be soft and damp without showing it on the surface. Lime mortar, old brick, and the raised foundations that many New Orleans homes sit on all have their own relationship with moisture, and a home that has stood for a century has had a century for water to find its way in.

The construction also means that a historic home is not a sealed box. Old windows leak, old doors do not seal, and the building breathes in a way that a modern home does not. That can be a help, because air moves through the building, and it can be a problem, because humid air moves through the building too. An inspection of a historic home needs to understand the building as it was built, not as a modern home would be built, and that understanding is part of what a good inspector brings.

Past flooding and storm history

Past flooding is the other factor that shapes a historic New Orleans home. Many of the city's older homes have been flooded, some more than once, and the water that entered the house may have left moisture in the walls, the floors and the foundations long after the visible damage was repaired. A home that was flooded and repaired quickly may carry hidden damp in the plaster and the wood, and the growth that follows can appear years later, in a wall that was never properly dried.

The history of the home matters, and it is worth asking about. When was the home flooded, how deep was the water, and what was done afterwards? Was the plaster replaced or dried? Were the floors lifted or left in place? Was the house dried with moisture readings, or was it simply aired out and repainted? The answers to those questions shape the inspection, and they are the reason a historic home deserves an inspector who asks about its past.

Mold in Historic New Orleans Homes: What to Look For — Louisiana mold guide

Ventilation in older homes

Ventilation in a historic home is a balance. The building was designed to breathe, with high ceilings, tall windows, and shutters that let air move through the rooms. When those features are kept, the home ventilates well, and the air moves. When they are sealed up, when windows are replaced with sealed units, when shutters are fixed shut, or when air conditioning is added without thinking about the airflow, the balance is lost, and the home can become damp in the places where the air no longer moves.

The habit of ventilating a historic home is worth keeping: opening the windows when the weather allows, keeping the shutters working, and letting air move through the rooms. A home that is sealed tight and never opened is a home where damp air sits still, and where mold can grow in the corners and behind the furniture. The old design of the house, with its high ceilings and tall windows, was a ventilation system, and it still works if it is allowed to.

What an inspection looks for

An inspection of a historic home looks for the signs that moisture has been in the building: staining on the plaster, peeling paint, soft wood, a musty smell, and damp patches on the walls and the floors. It looks at the places where water gets in: the roof, the windows, the doors, and the foundations. It looks at the places where water hides: behind the plaster, under the floors, and in the wall cavities. And it looks at the history of the home, asking about flooding, repairs and past mold problems, because the past shapes the present in an old building.

Moisture readings are part of the inspection, and they are particularly important in a historic home, because plaster and old wood can hold moisture without showing it on the surface. In a historic home, the inspector should explain the findings in plain terms, covering how far the growth reaches, where the moisture comes from, and what should happen next, so the owner can weigh the work against the age of the house. The mold removal page explains the work that follows.

Caring for a historic home

Caring for a historic home means respecting how it was built, and working with its design rather than against it. Keep the roof sound, keep the windows and shutters working, keep the air moving, and deal with leaks promptly. Ask about the home's history before you buy it, and keep the records of any work that is done, so that the next owner knows what has been found and what has been fixed. A historic home that is cared for is a home that will stand for another century, and a home that is neglected is a home that will show it in its walls.

Homes in New Orleans are among the most loved in Louisiana, and they deserve the same care as any home, with an understanding of what makes them different. An inspection that respects the building, and a remediation that follows the inspection, are the way to keep a historic home dry, and to keep its history in its walls rather than in its damp.

Repairs that respect an old building

Repairs in a historic home should respect how the building was built, because an old building works differently from a modern one. Plaster should be repaired with plaster, not with a modern material that seals the wall and traps moisture behind it. Old wood should be repaired where it can be, and replaced with matching wood where it cannot, rather than with a material that behaves differently. Windows should be repaired and kept working, rather than replaced with sealed units that change how the building breathes. These are general points, not a repair plan, and a contractor who understands old buildings is the person to ask about the details.

The principle is that a historic home is a system, and a repair that changes one part of the system changes the whole of it. A repair that seals a wall that used to breathe, or that replaces a window that used to ventilate, can create a moisture problem where there was not one before. A historic home that is repaired with respect for how it was built is a home that will stand for another century, and a home that is repaired without that respect is a home that will show it in its walls.

Key Takeaways

Historic homes are built with materials and methods that are different from modern construction, and those differences affect how moisture behaves in the building.
Past flooding is the other factor that shapes a historic New Orleans home.
Ventilation in a historic home is a balance.
An inspection of a historic home looks for the signs that moisture has been in the building: staining on the plaster, peeling paint, soft wood, a musty smell, and damp patches on the walls and the floors.
Caring for a historic home means respecting how it was built, and working with its design rather than against it.
Repairs in a historic home should respect how the building was built, because an old building works differently from a modern one.

Questions About Mold in Historic New Orleans Homes: What to Look For

Why are historic New Orleans homes vulnerable to mold?

Old materials such as plaster and old wood absorb and hold moisture, the building has more places for water to get in, and many homes have a history of flooding that may have left hidden damp in walls and floors. The layers of history are part of what makes the home vulnerable.

How does past flooding affect a historic home?

A home that was flooded and repaired quickly may carry hidden damp in the plaster and wood long after the visible damage was fixed, and growth can appear years later in a wall that was never properly dried. Ask about the flood history and what was done afterwards.

How should a historic home be ventilated?

By keeping its original design working: high ceilings, tall windows and shutters that let air move through the rooms. Sealing the home tight and never opening it lets damp air sit still. Opening windows when the weather allows keeps the air moving.

What does an inspection look for in a historic home?

Staining on plaster, peeling paint, soft wood, a musty smell, and damp patches, plus the places water gets in and hides: roof, windows, doors, foundations, behind plaster and under floors. Moisture readings matter, because plaster and old wood can hold moisture without showing it.

Your Next Step

If this guide matches what you found at home, the next step is a visit — not a guess. Call and describe what you found, and the visit is arranged from what you describe. The Mold Removal page explains what that service covers, and the mold remediation page explains how the full sequence works when mold has spread to more than one room.

Do not enter flooded rooms while you wait, and if water is leaking, turn off the shut-off valve for that fixture where you can reach it safely from dry ground.

Keep the guides on this site bookmarked: the first guide, the signs guide, and the preparation guide cover the checks worth repeating — after moving in, and after bringing used fixtures home.

Mold help is available across Louisiana. See mold remediation in Lafayette, LA for one local example, or find your town on the service areas page.