The short answer
How Lath Traps Moisture Under Floors
Lath refers to the narrow strips of wood that form a base for plaster ceilings and, in some older homes, plaster floors. This creates a deep, enclosed cavity beneath your floor surface. Water from a leak, spill, or high humidity can seep into this space and become trapped. The stagnant, damp conditions are perfect for microbial growth, which causes the unpleasant odor. Because the space is sealed, evaporation is very slow, allowing problems to develop over time.
The Link Between Odor and Mold Growth
The musty smell is a common sign of active mold or mildew. These fungi feed on the wood lath and any organic debris in the cavity. Their metabolic process releases microbial volatile organic compounds, which you smell. In some climates, indoor humidity from everyday activities like cooking or showering can create a localized damp environment ideal for mold behind walls or under floors.
Common Sources of Water in Lath Cavities
Several water sources can lead to this problem. Plumbing leaks from pipes running under the floor are a frequent culprit. Spills that seep through floorboards or a leaking appliance can also be the cause. Sometimes, chronic high indoor humidity condenses on cooler surfaces within the cavity. You need to find and stop the moisture source to solve the smell permanently. Ignoring it can lead to more extensive wood rot and structural issues.
- A slow leak from a supply line or drain pipe.
- Historical flooding or a major spill that was not fully dried.
- Condensation from high indoor humidity on cold surfaces.
- A roof leak that traveled down inside walls to the floor.
- Improper ventilation in crawl spaces or basements below.
Steps to Diagnose the Problem
Start by checking for visible signs of water damage on the floor surface, like staining or warping. Feel for soft spots or a spongy feeling when walking. Use your nose to try and locate the strongest point of the odor. Since the lath cavity is hidden, a professional moisture inspection is often needed to map the full extent of the wet area accurately. They use tools that can detect moisture behind surfaces without causing unnecessary damage during the initial investigation.
Why Professional Help Is Often Necessary
Addressing a lath smell usually requires accessing the enclosed cavity, which means removing flooring and possibly plaster. Local water damage pros have tools like moisture meters and infrared cameras to find wet areas without unnecessary demolition. They follow drying protocols to prevent further damage and mold spread. This work is complex and often ties into larger structural drying needs. Proper drying requires industrial equipment and careful monitoring to ensure all layers of material are dry.
- Specialized equipment detects moisture you cannot see.
- Proper containment prevents mold spores from spreading.
- Correct drying protects structural wood from rot.
- They can identify if floor replacement is necessary.
- Their process helps document damage for an insurance claim.
- They ensure the space is dry before reconstruction begins.
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Call Now (208) 537-2633Frequently asked questions
Can I get rid of the smell myself?
Surface cleaning may temporarily mask the odor, but it will return if moisture remains in the lath. The cavity must be opened, dried, and contaminated materials removed. This is a significant demolition and drying project, which is why many homeowners seek professional help to properly address the underlying water damage and mold.
Is the smell dangerous to my health?
A persistent musty odor often indicates mold, which can cause allergic reactions or respiratory irritation for some people. If you or family members experience new or worsening symptoms like coughing or headaches, see a doctor. The space should be inspected by a qualified mold professional.
Will my homeowner's insurance cover the repair?
Coverage depends on the source of the water damage. Sudden, accidental leaks like a burst pipe are often covered, while damage from long-term seepage may not be. Policies vary, and your insurer decides what is covered. Check your policy details and document the damage thoroughly.