Photograph of  termite damage to the floor structure of a 1920's home.Identify Termites: How to Detect, Evaluate and Prevent Structural Damage from Termites
     

  • TERMITE IDENTIFICATION & CONTROL home - CONTENTS: How to Spot Termite Damage: Case Report of Un-Noticed Termite Activity. How to prevent termite attack & termite damage on buildings. How to evaluate termite damage to wood structures. Where & how do termites attack buildings.
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Termites & termite damage inspection, treatment, prevention: termite information in depth, including termite inspection case reports, field photos and advice. This article discusses how to recognize termites & termite damage, & how to cure or prevent termite damage on buildings.

This article provides termite damage photographs, termite inspection advice, and lists additional articles that discuss the inspection, detection, prevention, and repair of structural damage from termites. We describe the use of termite control by bait traps, chemical poisons, and termite shields, and we include photos & warnings about amateur termite treatments.

Preventing these problems by good design and by building maintenance is preferred to simple chemical applications around a property. When use of pesticides is required, there are some important choices that we will discuss.

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How to Spot Termite Damage: Case Report of Un-Noticed Termite Activity

Termite identification sketch (C) Daniel Friedman Carpenter ant sketch

Article Series Contents

- David Grudzinski

[Referring to the termite damage photos shown just below] I found this termite damage in a house yesterday. The shelter tubes were so large, they were hanging out of the wood. The termites have been in this house for many years, and this sign is that there is a large infestation that has caused sever damage to the house.

The main 10x12 center structural beam was so damaged, that about 3/4 of it will have to be replaced.

Termite damage photographs (C) D Friedman D Grudzinski Termite damage photographs (C) D Friedman D Grudzinski

This is a significant structural issue with a house. If the homeowners had known what to look for, this may have been caught before the damage was so severe. As you can see form the cob webs, they rarely went there, and did not clean well, so the damage was missed until it was severe.

Termite damage photographs (C) D Friedman D Grudzinski Termite damage photographs (C) D Friedman D Grudzinski

We provide a more lengthy case study of a termite inspection that found severe, covered-up and improperly-repaired termite damage at TERMITE DAMAGE INSPECTION. There photographs show a sequence of clues leading to the discovery of the termite problem.

Termite Mud Tubes - Indicators of Termite Activity

Details about termite mud tubes, where they are found, what they look like and what they mean are now found at TERMITE MUD TUBES. Excerpts from that article are just below

Our termite damage photograph at below left illustrates that carpenter ant activity (frass or loose "sawdust) may be found in the same location as termite activity (the mud tubes).

Signs of risk of termite attack (C) Daniel Friedman Signs of risk of termite attack (C) Daniel Friedman

Our second termite mud tube photo (above right) is more clear and shows branching termite mud tubes running along the surface of a floor joist.

Reader Question: We noticed some hard stalagmite looking things (pictures attached) in our basement and we were wondering if these are from termites? - G.M. 8/3/2014

Hanging termite mud tubes or termite stalactites (C) InspectApedia GM Hanging termite mud tubes or termite stalactites (C) InspectApedia GM

[Click to enlarge any image]

Reply:

I'm sorry to say yes, that looks like significant and active termite activity. The hanging mud tubes are the critters' exploration for another wood contact avenue besides the beam that they already infest.

Because those hanging mud tubes are quite fragile I infer from your photographs that either they are located in an area where no one has passed for some time or the termite activity is voracious.

More of these termite mud tube photos and our recommended actions are now found in this separate article:
TERMITE MUD TUBES

Termite Mud Tubes Outdoors

Details about termite mud tubes found outdoors are now found
at TERMITE MUD TUBES OUTDOORS. Excerpts are just below.

Arizona termites exposed in sunlight (C) D Friedman M Gieseke

Termite mud tubes may appear on the outside (photo at left) or inside of building walls or other structural components (photo at left) or they may appear on the ground itself (below left). These Arizona termite mud tube photos just below were contributed by our Arizona correspondent (and daughter) Mara Gieseke, Tucson AZ

Break Open Termite Mud Tubes?

Details about the effects of breaking or disturbing a termite mud tube are now found
at TERMITE MUD TUBES IF DISTURBED. Excerpts are just below.

Signs of risk of termite attack (C) Daniel Friedman

Disturbing a termite mud tube is shown by my pen in the photo above. If you disturb a mud tube and termites fall out you know for sure you've found an active colony. If you disturb a mud tube and don't see any termites, you'll need more information and probably a more expert inspection.

Termite Damage Indicators, Inspection Clues, Where to Look

Termite damage case (C) Daniel FriedmanAt left is a closeup photograph of "mud" extracted from termite damaged oak floor.

Our photograph at below left shows two signs that should tip off any inspector of a high risk of hidden insect damage: the wood siding is brought close to the ground, perhaps also at a building corner where a downspout or roof drainage spills. Water plus wood plus proximity to the ground surface add up to a high risk of insect attack.

Add the observation that an amateur-workmanship wood "skirt" was nailed against the bottom of the foundation, very possibly covering up damage, and this is a red flag for termite or carpenter ant attack.

Our second insect damage risk indicator is the photo at below right: a collection of pesticides, some of them perhaps old and no longer permitted for use by homeowners, found in the building is often a clue that termite or other insect poisoning or treatment was performed by someone other than a licensed pest control applicator - risking not only incompetent ineffective work, but possibly environmental contamination that can be a risk even to the building occupants.

Signs of risk of termite attack (C) Daniel Friedman Signs of risk of termite attack (C) Daniel Friedman

We discuss the inspection and detection of severe termite damage in added detail
at TERMITE INSPECTION & DAMAGE ASSESSMENT

Building Features that Invite Termite Damage Tell Us Also Where to Look for Termite Attacks

Do wood forms left between a footing and stem wall increase the risk of a termite attack

I have inspected new construction home last week. There were some 1x4 wood forms left in between of footing and stem wall.

(Left over footing forms) Is this creating structural or pest problems in future?

Please let me know if I need to do some actions before the house close. Thanks - T.N.

Reply: Yes in many instances. Best practice is to remove wood forms close to or in contact with the soil around a building. Don't leave wood buried around a building.

Wood concrete forms (C) D Friedman T KA competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem including evidence of present or prior wood destroying activity at a building (termites, carpenter ants, powder post beetles, carpenter bees, other wood destroying insects (WDI)) or an experienced inspector can cite construction details that increase the risk of a termite or other WDI attack in the future.

That said, for your building and based on the photo you provided (above left) does not look too risky in that there is good visible access to the lower foundation wall to observe any future termite mud tubes or other signs of insect activity.

Watch out: there could be other termite-attack risk factors not shown in the photo at above-left. These details are discussed in the articles cited immediately below. Also I don't like seeing that insulation left on the crawl area floor.

Details about outdoor indicators of termite activity and construction details likely to invite termite attack on the building are found at TERMITE DAMAGE INSPECTION

Because insect damage on buildings is very often related to locations of water leaks or moisture traps, readers should also see WATER ENTRY in BUILDINGS.

Termite Damage Photographs Confirm Extent of Structural Damage

Termite damaged ceiling joist (C) Daniel Friedman Termite Damaged floor sill (C) Daniel Friedman

When observing termite damage such as in the wood framing members in our photo at below left, an expert will explore adjacent members (probing and visual inspection) as well as the infected members to discover the extent of damage.

At above right our screwdriver has fully penetrated the sill plate at the bottom of an interior partition wall in a home where we found extensive termite damage.

And at below right our screwdriver penetrates the termite-infested wall stud between the sill and ceiling. [Click to enlarge any of our images.]

Photograph of  termite damage to the floor structure of a 1920's home. Termite Damage (C) Daniel Friedman

Wood destroying insects may enter a single wood member such as a floor joist and travel along just that member, or depending on site conditions and age of the WDI infestation, many structural members may be involved.

Photo Guide to Drywood Termites & Other Insects that attack wood structural components above ground and in dry climates

Insect damaged door (C) Daniel Friedman San Miguel de Allende MexicoThe photographs of drywood termites and termite damage shown here illustrate termite damage in the Southeastern U.S. (Old Tucson, AZ) and Central Mexico (San Miguel de Allende, GTO).

 

This severely damaged wood was caused by a type of "dry wood" termites that attacked a stucture we inspected in Tucson, AZ.

This wood segment was a nailer set into an otherwise solid adobe structural wall.

Here we see an example of insect attack on a wood component that was not in ground contact and was not exposed to an unusual water source or leak.


Insect damaged door (C) Daniel Friedman San Miguel de Allende Mexico

In the insect damage photo above we illustrate what we think is not termite damage but wood borer damage to an antique wood door, San Miguel de Allende, Guanajuato, Mexico. But as additional photos illustrate, termite damage is indeed also found in this location.

Some Termites do Not Attack Structures - Gnathamitermes tubiformans Desert Termites Photos

A local exterminator visited this site and identified the termites in our photographs above as Desert Surface Termites [or by some sources just "desert termites" or Gnathamitermes tubiformans.] Gieseke passed on these details: desert surface termites, according to local exterminator Truly Nolen, are fatter than other types of termites.

They do not attack structures. If you were to leave a 2x6 piece of wood in the yard, they would cover it with their mud but they would not eat into it. They would just eat the very outer layer.

Bottom line: desert termites may not attack your building, but they may eat your plants. Details are in this PDF
file: DESERT TERMITES.

Gieseke's photos below show the mud tubes of Desert Surface Termites on the ground surface near Tucson AZ.

Signs of risk of termite attack (C) Daniel Friedman Signs of risk of termite attack (C) Daniel Friedman

More about Desert Termites is provided at our references below.

In general, termites' natural home is in the soil where they attack wood below ground, coming up to higher wood found where there is convenient access, and, depending on the species, moisture.

Your termites are almost certainly subterranean termites as you are finding them living in the ground. (Drywood termites, unlike subterranean termites, do not require direct access to a moisture source and are often found attacking wood above ground level.) Perhaps when you first disturbed the mud tubes on the ground, soil moisture had been so great (following recent rain in Tucson) that your local subterranean termites were coming to the ground surface.

In most of the U.S. only subterranean termites are found, but along the U.S. southern border (including southern Arizona) and further south, both drywood and subterranean termites may be found. In North america north of the U.S. termite damage is less common.

Drill Marks or Old Containers May Mean Amateur Termite or Other Insect Extermination Attempts that May be Unsafe

Pesticide abandoned indoors (C) Daniel FriedmanAt left we illustrate a clue suggesting a do-it-yourself pesticide applicator may have been at work.

Below left our photograph shows homeowner-drilled holes in a building rim joist - perimeter framing. This do-it-yourself termite treatment involved drilling and spraying a termiticide or chemical onto and into the wood.

Because of the age of the home (1700's) and amateur work, we were concerned that Chlordane, a toxic, now banned termiticide may have been used as this chemical was previously available for easy purchase in home and garden centers.

Indeed, our test-cut sliver of test wood taken rom the rim joist was confirmed by a chemical test laboratory as having been soaked with Chlordane - a toxic chemical with a long half-life. The building needed further evaluation for the extent of chemical contamination in order to decide if remediation (removal or sealing of treated wood) would be needed.

Signs of risk of termite attack (C) Daniel Friedman Signs of risk of termite attack (C) Daniel Friedman

Our second termite treatment clue photograph (above right) shows a drill mark in a concrete and slate patio outside and abutting a home foundation wall. Regularly spaced drill openings, 18" to 24" apart in a concrete basement floor slab set just inside the foundation wall, or around the outside of a foundation where sidewalks, driveways or patios are installed, are a likely indicator that a professional PCO has pumped a termiticide barrier around the building.

This means you will want to inspect the structure for prior termite damage in order to be sure that further repairs or treatment are not needed.

At Carpenter Bee Holes & Powder Post Beetle Holes we show other holes in wood that are made by insects but that are sometimes mistaken for electric drill holes.

See PESTICIDE EXPOSURE HAZARDS for details about the health hazards of exposure to pesticides used or applied indoors.

Comparing Termite Damage to Powder Post Beetle / Old House Borer Damage

Details about powder post beetles and old house borer insect damage on buildings are
| at
POWDER POST BEETLES. Excerpts are below.

At DRILL MARKS we show drill marks in wood caused by an amateur pest treatment attempt. While to an experienced eye, holes in wood caused by insects are easily distinguished from those caused by humans using a drill or hammer and nail, on occasion someone is fooled. Here we illustrate two cases of holes that are caused by insects, not mechanical events on buildings: powder post beetle holes in wood, and carpenter bee holes in wood.

Powder post beetle old house borere damage photographs (C) D Friedman D Grudzinski Powder post beetle old house borere damage photographs (C) D Friedman D Grudzinski

In our powder post beetle photos above, while there was significant beam damage, the infestation did not appear active.

Powder post beetle damage is typically treated with a topical insecticide spray. Some pest control operators (PCOs) also spray paint the wood surfaces in order to make it easier to spot a renewal of insect activity in the future.

We look for the presence of fine wood powder around the insect exit holes or on the ground below the damaged infected member as indications of recent insect activity.

See POWDER POST BEETLES for details about this topic.

Termite Bait Traps as a Method for Termite Control

One method for stopping or avoiding termite attack on buildings involves the placement of termite bait traps around the building. Our photo (below left) illustrates a termite bait trap set outside and close to a stone foundation wall. At below right we see termite bait traps spread at a typical interval around a building that had been subject to termite attack.

Signs of risk of termite attack (C) Daniel Friedman Termite bait trap (C) Daniel Friedman

Watch out: don't assume that because there is a masonry block, brick, or stone foundation that a building is termite proof, even when there is good clearance between the soil top and wood framing. With sufficient invitation (leaks, water) termites find easy passages trough stone, concrete block and brick foundation walls to wood framed sills, rim joists, and floor structures above.

  • The termite bait trap approach relies on regular trap inspection by the pest control operator.
  • When termites are discovered attacking one of the tasty wooden bait stakes, the stake is replaced (by the PCO) with one containing a chemical intended to poison the termites.
  • Some may not realize at first that the cost of this termite damage prevention system is more than the initial cost of installing the termite bait traps. The building owner needs to assure (and pay for) regular inspection and maintenance of the termite traps.

Watch out: If the termite bait trap system is not being regularly inspected, you have put out termite-attracting wood around the building perimeter without following through with the proper steps, and in our OPINION you may actually have increased the risk of a termite attack. Be sure your termite bait trap system is being inspected regularly. If we see termite bait traps that are abandoned, overgrown, covered with leaves and debris we know that the traps are not being inspected regularly.

See TERMITE SHIELDS vs TERMITICIDE for details about comparing methods of preventing termite attack on buildings. Below are two photographs of termite bait traps to help you recognize termite bait traps when you see them. This approach avoids placing a chemical barrier around the building to stop or prevent termite attacks.

Signs of risk of termite attack (C) Daniel Friedman Signs of risk of termite attack (C) Daniel Friedman

Guide to Use of Termite Shields on Building Foundations as a Termite Barrier

Figure 1-3 Termite Sheilds (C) Wiley and Sons - S BLissAs discussed in Best Practices Guide to Residential Construction:

Metal termite shields are widely used atop foundations in the southern United States and in tropical climates as a physical barrier to termites. They sit directly on top of foundation walls, piers, and other supports before the first piece of wood is installed (see Figure 1-3 at left).

At one time termite shields were thought to block the entry of subterranean termites, the most widespread and destructive wood-boring insect in the United States.

However, subterranean termites, which nest in the soil, will exploit the tiniest gaps in termite shields or other barriers to reach the wooden portions of a house and will build tunnels along exposed foundation walls and around termite shields if necessary.

Although the shields do not stop termites, they slow down their progress and force them to build their tunnels in the open where they can be easily seen during inspections.

To work at all, the termite shield must have tightly sealed joints and be sealed around foundation bolts and other penetrations. Joints can be either soldered or mechanically interlocking. If the barrier is unsealed, termites will find any small gaps and render the effort worthless.

Below our termite mud tube photos show that a termite shield appears to have been installed along most but not all of the building foundation top. Or was it? We don't know if this is wall flashing that leaves sills exposed just under the wall edge, or whether the flashing extends across the foundation to the interior (as recommended).

But our second termite photo (below right) shows a termite mud tube ascending the same foundation wall and passing under the termite shield. The shield makes it more difficult, but not impossible, for termites to attack a building.

Signs of risk of termite attack (C) Daniel Friedman Signs of risk of termite attack (C) Daniel Friedman

TERMITE SHIELDS vs TERMITICIDE gives a discussion of termite shields and insect attack on buildings using foam board foundation insulation.

More installation details for termite shields and other building flashing can be found
at FLASHING WALL DETAILS.

 

Continue reading at TERMITE DAMAGE MUD TUBES or select a topic from the More Reading links shown below.

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TERMITE IDENTIFICATION & CONTROL at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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