Dry Rot & Brown Rot in Crawl Spaces

Solving Dry Rot Issues

Dry rot (also known as brown rot) is one of the most severely damaging decaying forces on household wood in the world.

Approximately 20 billion board feet of timber are destroyed by wood rot in the United States each year -- far more destroyed wood than is damaged annually by fire!

Replacement wood used to repair damage caused by wood rot accounts for almost 10 percent of the annual wood production in the U.S. alone.

In the United Kingdom, dry rot problems have been credited for dealing about 150 million pounds worth of damage annually, and wood rot in general leads to about 17 billion dollars of damage each year in the United States.

Dayton's Pest Control has a long history of experience in eliminating, preventing, and controlling dry rot infestations.

What is Dry Rot & Brown Rot?

"Dry Rot" is a term most often used to describe a particular kind of dry, cracking, rotting wood. However, dry rot occurs because of a variety of brown rot species, most notably the "true" dry rot fungus known asSerpula lacrymans. It originally got its name from the thought that it did not need water to survive and used a fermentation process to survive. Research has long since been proven untrue, and it is now called, more appropriately, "brown rot", although the old name hangs on.

Dry rot needs much less moisture than other types of wood rotting fungi--a wood moisture content of at least 28-30% -- to survive. While there is no official proof on the subject, many contractors have observed that dry rot also will not grow on wood with too much moisture.

Protect Your Home From Dry Rot!

The Bad News
The Good News
  • While dry rot is not the most common type of rot, it can deal serious damage to your home and endure conditions that are too dry for other types of rot to thrive. In fact, up to a 75% loss in the toughness of the wood [PDF] is possible with just a 1% decrease in the wood's weight of the wood.
  • Dry rot fungus spores are present in most homes and can survive for several years, waiting for the right conditions to grow.
  • Dry rot can pull moisture from moist areas to dry areas. It grows through mortar, concrete, masonry, and behind plaster.
  • Despite its name, dry rot needs moisture to produce spores-- at least 28-30% moisture content within the wood with a relative humidity of 95% or higher. Most softwood timbers in dry homes, especially in the upper levels, have a moisture content of 12-15%.
  • Dry rot problems in basements and crawl spaces can easily be solved by controlling moisture by sealing and dehumidifying the space.
  • Treatment of the wood with fungicides and products such as boric acid are known to eliminate and prevent dry root fungi.
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Identifying & Treating Dry Rot or Brown Rot Problems in Tennessee

A common first indication of dry rot in a home is the appearance of a "red brick dust".

This red dust is actually an accumulation of fungal spores that are covering the surface, waiting for the proper conditions to start to grow.

When Does Dry Rot Damage Occur?

An outbreak of dry rot commonly occurs several months after a household water event, such as flooding, bursting washing machine hoses, a failed water heater, or leaking pipes. In some cases, water or moisture may have been trapped in a building cavity as the home was being built.

Dry rot is also common in vented crawl spaces and basements with groundwater flooding. It's often not detected until the damage is already very significant.

Steps to Dry Rot Cleaning & Repair

  1. Remove Damaged Wood: All wood that shows decay or visible fungus should be removed, as well as all wood within one meter of the visible decayed material.
  2. Remove Materials Near Damage: Plaster, paneling, linings, and ceilings around the dry rot areas can also contribute to the damage and should also be removed.
  3. Clean The Area: Using a wire brush, clean off all surfaces, including metal and pipes, within 1.5 meters of the furthest edge of the infection. Clean up all dust and debris from the work.
  4. Kill Any Remaining Fungi: Apply a fungicide to all masonry, concrete, and exposed dirt in the area. Apply two coatings of fungicide to all wood surfaces within 1.5 meters from the damage.
  5. Rebuild: Replace wood rot infected timbers with fungicide-treated wood.

Preventing Dry Rot in a Basement: Remove all standing water sources, then install a plastic vapor barrier on the walls and floors. Install a self-draining dehumidifier powerful enough to dry the area. (At least a 100-liter model)

Preventing Dry Rot in a Crawl Space: Seal off all crawl space vents and door covers. Encapsulate the crawl space with a crawl space liner, then install a self-draining crawl space dehumidifier.

Dry Rot Alert!

Architect's Journal reports that dry rot can grow through damp mortar, concrete, masonry and behind plaster.

This makes remediation of dry rot complicated and expensive, and it can lead to future problems with dry rot if it is not treated properly.

Preventing Dry Rot Problems in Your Basement or Crawl Space

Dayton's Pest Control can help you eliminate dry rot problems at their source. We can dry your basement or crawl space, eliminate flooding problems, and seal out humidity.

This not only eliminates dry rot problems, but also creates an environment that is inhospitable to mold, wet rot, and mildew, while helping to keep out termites, carpenter ants, cockroaches, crickets, and other household pests. Crawl space sealing products can also do double duty as insulation, providing you with added energy efficiency.

We offer FREE, no-obligation dry basement and crawl space quotes in our service area. We can answer all your questions and point out the sources of humidity and moisture in your home.

We service Tennessee, including Knoxville, Maryville, Sevierville, Oak Ridge and nearby areas such as Clinton, Lenoir City, Powell, Harriman .