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Learn To ID And Repair Dry Rot Before It Is Too Late

Omid Ghanadiof

Jul 10, 2022

Dry rot and Balcony inspection

Learn To ID And Repair Dry Rot Before It Is Too Late

Our world is experiencing all kinds of materials shortages, especially in building materials, due to fallout from COVID-19 and supply chain interruptions. Hyper-inflation, excessive rainfall, and extreme heat aren’t helping either. As a result, repairs or new construction are costly for apartment owners and homeowners.

Dry rot, otherwise known as Serpula Lacrymans, is a particularly problematic, gut-wrenching, and distressing issue to repair. It is a fungal infection of wood that destroys and decays the material as it spreads. The fungus thrives in wet timber and poorly ventilated spaces. Dry rot hides in areas not readily visible such as roofs, attics, crawlspaces, stairs, floors, walls, flashings, windows, downspouts, balcony, deck, and gutters. Damaged wood shrinks, becomes soft, even spongy, brittle, and flakes off in layers.

Rotted materials are weak. If dry rot is allowed to grow unchecked for years, it can make an apartment building or home uninhabitable and unhealthy. “Deck and Balcony Inspection Bill,” Sb721 went into effect in California on January 1, 2019. It was enacted in response to a balcony collapse in Berkeley at the Liberty Gardens Apartments that resulted in the deaths and serious injuries of those occupying the structure at the time. The worst-case scenario is irreversible structural damage, often resulting in expensive repairs or demolition of a property. No one wants that! The sooner the mold is identified and its food supply is cut off—the better.

How Do To Identify Dry Rot?

Dry rot has a four-stage life cycle:

  1. It begins with dormant spores until moisture content exceeds 20 percent in a piece of timber, and a poor airflow situation presents itself.

  2. Hyphae or thread-like appendages grow and expand outwards, absorbing moisture.

  3. The thread or mycelial growth continues until it looks like cotton or wool. Sometimes the fibrous growth has a gray, yellowish, or light purple tint.

  4. The fungal life cycle ends as spores are produced as the fungus’ food source is depleted. The fungus dries out, turns into a white powder, and a foul odor develops in its proximity. The cycle starts again when conditions are optimal.

How Do To Repair Dry Rot Damage?

The most straightforward answer is—it depends. That might sound overly simplified, but it is true. Some types of damage are easier to mitigate and repair due to the extent of mold’s progress through a wooden structure. Dry rot can spread like wildfire under the right circumstances. Remediation programs will look very different from one project to another. For example, an apartment building may have different needs than a hotel, business office, or historic home.

The first step in developing a custom remediation program involves hiring the right professionals. An expert inspector will be able to identify problem areas quickly and evaluate the severity of dry rot, and then make the appropriate recommendations to stabilize or replace damaged timbers. This person(s) can help property owners find crews to complete the necessary work. Property owners must be forewarned; program suggestions could be considerable and cost-prohibitive, especially for historic buildings.

Various strategies to repair dry rot damage involve:

  • Dehumidifiers, fans, sump pumps, and encapsulation.

  • Removal of affected wood, plaster, or drywall.

  • Applying chemical preservatives such as paint or pastes to conserve undamaged wood.

  • Replace damaged timber with wood pre-treated with fungicides and insecticides.

  • Clean all brickwork that shows signs of fungus growth, allow it to fully dry, and then treat with a chemical that acts as a barrier preventing further mold expansion across the masonry surface.

  • Heat sterilization of brickwork or timber may also be a non-toxic way to inhibit fungal growth.

Dry Rot Prevention

The best method for dealing with dry rot is prevention. Builders can use pre-treated construction materials for wooden structures and create proper landscape drainage in and around buildings. French drains, pop-up drains, and well-installed gutters will move water away from the building. If moisture never reaches the wood in the first place, then dry rot can’t grow.

Another successful method includes proper ventilation of attics, basements, and crawlspaces. Builders have multiple ways of addressing these needs based on a customer request. Dry rot only grows in poorly aired areas.

Apartment owners and homeowners can also have their properties regularly inspected for water damage or leaks. Routine inspections of balcony, walkway, deck, stairways, will help prevent future issues or help identify them quickly. A systematic and preventative approach like what designed in sb326 and sb721 will save money and diminish costly repairs. Apartment owners, tenants, and homeowners can sleep better at night, not worrying if a silent monster is creeping in the walls and eaves at night.

Talk to the California professional structural engineering firm to find out more at [].

Omid Ghanadiof

Omid is co-founder of EEE advisor engineering firm that Specialized Engineering Structural Inspection Firm active in southern California to help owners and HOAs to comply with Balcony inspection ordinance SB-721 and SB-326

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