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What do Termite Mud Tubes Look Like?

What is a termite tube, or termite tunnel?

Subterranean termites connect their colonies in the soil underground to their above-ground food sources via mud tubes (sometimes known as galleries or tunnels). These tubes are made from soil and wood combined with termite saliva.

Subterranean termites require moisture to survive and are vulnerable to dehydration. Subterranean termite tubes offer shelter that locks in moisture, and protects the termites from dry air and predators.

Picture of Mud Tube Made by Subterranean Termites

Mud Tube Made by Subterranean Termites

Types of Subterranean Termite Mud Tubes

There are four types of mud tubes that are used by subterranean termites:

  • exploratory

  • working

  • swarming castle

  • drop tubes

While mud tubes function to protect termites, these structures serve different purposes for the colony.

Exploratory Tubes

Exploratory tubes are thin and fragile, yet easy to see because they branch out in multiple directions. They, like other tube types, are made of feces, saliva, and dirt and can extend up to 15 feet above ground when built over concrete or metal.

Used to search for sources of food, exploratory mud tubes rise from the soil, but they do not connect to any wood. These tubes are typically fragile and abandoned by the time homeowners come across them. Although the tubes are empty, they still indicate the presence of termites. The pests will have moved to other sections of the home to find accessible food.

Working Tubes

Working tubes, also known as utility tubes, receive the most use from termite colonies. They transport hundreds to thousands of termites from nests to food sources daily. Working mud tubes are loosely organized like a highway, with some lanes used to carry food while the others are used for construction and repair.

These tubes typically measure between 1/4 and 1 inch in diameter. While they're constructed of the same materials, working tubes are made to last longer than exploratory tubes. Utility mud tubes allow termites to travel long distances along basement walls and home foundations. They may also be found around sills, sub floors, joists, window frames, and under porches.

Picture of Subterranean Termite Mud Tunnel on Wood

Subterranean Termite Mud Tunnel on Wood

Swarm Castle / Swarm Tubes

Imagine this picture – during rush hour a car has broken down right in the middle of one of the busiest intersections in the city. The result is pure havoc as motorists maneuver around each other trying to avoid hitting someone and creating an even more chaotic scene. This is a somewhat accurate analogy of what it is like when swarmer termites begin moving into position to fly away from their colony. However, termite workers step in to make things orderly.

Termite workers construct swarm castles that are designed to temporarily accommodate the numbers of termite swarmers leaving the colony during a swarm. Swarm castles can be very large, up to and larger than four feet wide. Since termite swarmers are delicate, they are subject to damage when the hosts of swarmers begin leaving the colony, and protection is needed to keep the swarmers intact, healthy, and functional. Protection is why the swarm castle is built.

The actual location where swarmers gather before leaving the nest is smooth and free from debris. When the time is right, workers begin to direct swarmers to the protective castle and the swarmer termites move through the numerous exit holes, take flight, and begin the process of establishing other colonies.

Drop Tubes

Drop tubes are suspended between the ground and wood members of the structure. They're easy to identify because they look like stalagmites in caves. Their purpose is to make food sources more accessible to termite workers and to re-establish a connection with the ground and working tubes.

Drop tubes are lighter in color than exploratory or working tubes because they contain more wood fibers. However, they have a similar diameter and brittleness to exploratory mud tubes.

Image of Termite Mud Tube in Building Crawl Space

Termite Mud Tube in Building Crawl Space

Damage Caused by Mud Tubes

Termites cause significant structural damage over time. Though mud tubes are not a problem by themselves, they allow termites to wreak their havoc, all while maintaining the proper moisture content that keeps termite workers from drying out and dying. Homeowners should keep an eye out for mud tubes because they are one of the first signs of a termite infestation.

What Do Termite Mud Tubes Look Like?

Subterranean termite tubes are 1/4 to 1 inch in diameter. They can be noticed easily when present along exterior concrete walls or a home's foundation. However, subterranean termite tubes also may be hidden in typically inaccessible places, such as inside walls, crawlspaces, cracks in the foundation or behind baseboards.

What does termite damage look like?

Termite Damage in Subfloors

To understand how a termite may cause damage to a subfloor, it’s important to know that a floor is made of three layers: the supports (called joists), the subfloor and the finished layer (hardwood, tile, or carpet). The joists support the subfloor and the subfloor is attached to the tile, hardwood, or carpet.

Termite damage in the subfloor can affect the structural integrity of the home and cause movement in the floor. The floor may squeak as boards rub against each other or against nails. A damaged subfloor may sag, and the top layer of tile or hardwood flooring may pull away from a sagging subfloor. Termites are not the only reason hardwood flooring or tiles can pop loose, but it’s a good idea to call your Orkin Pro to check for termites if you have floor problems.

When termites damage the subfloor, they frequently damage the adjacent floor joists. Before beginning repair work, confirm your Orkin Pro and contractor have inspected all nearby structural timbers for damage.

Image of Termite Mud Tube in Building Crawl Space

Termite Mud Tube in Building Crawl Space

As these pictures of termite tunnels show, mud tubes are earth-colored and typically about the width of a pencil, though they may range in diameter from 1/4 inch to 1 inch.

Termite Tunnel on Wood Beneath a Home

Image of Termite Tunnel on a Piece of Lumber

Termite Tunnel on a Piece of Lumber

Termite Damage in Windows and Window Screens

If you’ve noticed that your wooden windows and doors are more difficult to open, you may want to do a further inspection for a possible termite infestation. Termites in window frames tunnel their way through, bringing moisture along with them — which causes frames to warp, go stiff, or get stuck.

Termites typically feed on wood from the inside out, leaving a hollowed-out piece of wood over time. As they tunnel their way through wooden doors or window frames, you’ll hear a hollow sound when you tap on an area with major termite damage. Early signs of termites can be seen or heard on window and door trim, exposed beams, and other common places for termite mud tubes.

Picture of Termite Mud Tunnel Built on Window Screen

Termite Mud Tunnel Built on Window Screen

Do Termites Eat Plywood?

Although termites are known to feed on a variety of things, termites prefer to eat wood — some types over others. Unfortunately for homeowners, the most common subfloor materials are wood-based and susceptible to termite damage. In fact, termites prefer these softer woods to hardwoods and may cause significant damage to the subfloor before feeding on hardwood floors. Plywood is the most common subfloor material in recently-built homes.

Plywood provides a nice meal for termites and is susceptible to an infestation unless it has been pressure treated. If chemicals such as preservatives, anti-pesticides, and antifungals are injected into the lumbar, termites won’t see plywood as a viable target for tunneling.

Image of Termite Mud Tube on Plywood

Termite Mud Tube on Plywood

Picture of Termite Mud Tunnel on Older Plywood

Termite Mud Tunnel on Older Plywood

How to Tell if a Termite Tunnel is Active

Wondering if you have an active termite infestation? Just because you don’t see little winged swarms doesn’t mean you’re out of the woods. Even though a telltale sign of an active infestation is an accumulation of termites flying around your windows or foundation, there are a few other signs that also indicate a problem. If you see piles of discarded wings, feces, mud tubes, or tunnels, you may be dealing with a pest control issue that’s worthy of contacting an expert.

If you suspect termite activity on your property, make sure to contact an expert in termite identification as soon as possible. Orkin Pros are trained to address any current signs of termites in a house, as well as implement solutions to help prevent future issues. Through a specialized approach to termite control, Orkin can help protect your home with a plan suited to your specific needs.

Don’t let termites eat through your home — learn how to find termite tunnels and protect your home. Call your Orkin branch to schedule a free termite inspection.


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