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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.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
Article Series Contents
[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.
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.
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 Damage Mud Tubes Photographs Suggest Where to Look
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).
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.
Watch out: termites prefer to tunnel inside of wood and can cause extensive damage without appearing readily on the wood surface. Mud tubes are typically built to enable movement across a less hospitable surface such as masonry walls or wood that was just not so nice to penetrate. Termites had traveled extensively in the ceiling joist shown in our photo at below-left. The sill plates located on the floor in this same room were also infested (photo below right).
Below our termite mud tube photos illustrate how extensive branching mud tubes may be found on building foundation walls headed for wood framing members and even along metal pipes. At below left it appears that termites entered through a crack in the foundation wall, then built mud tubes upwards looking for a more hospitable wood material.
Below our termite mud tube photos illustrate the importance of a careful, expert termite inspection. The mud tubes at below left are close to and tightly located against the junction of subfloor and rim joist, and the butt end of a floor joist and rim joist and are not as easy to spot as our earlier termite photographs.
And at below right we demonstrate that termites might run along the interior of an old wooden beam; we found these termite tunnels by probing inside the large open checking or splits that would normally be considered not a structural concern, but adding termite damage can change that evaluation. See SPLITS & CRACKS in STRUCTURAL WOOD BEAMS for more about log and beam checking or splitting.
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.
We discuss the inspection and detection of severe termite damage in added detail at TERMITE INSPECTION & DAMAGE ASSESSMENT
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.
A 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
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.]
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
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.
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.
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 who reports:
So what do you think of these Arizona Desert Termites ... I went out back today to try and get some pictures for you. I got one photo of the termite mud tubes that are on a masonry retaining wall that is quite a distance from our house.
Then I swiped my shoe over the mud trails (below left) that I saw in the dirt, but there were no termites in any of them. Where did they go? The other time I kicked open a termite mud tube there were at least 50 Arizona termites squirming in the mud (below right).
[Mara Gieseke's termite photo (above right) shows Arizona termites squirming in the sunlight just after she disturbed their ground-surface mud tube. We have enlarged this photo to make the termites easier to see, but notice how difficult it is to spot them against the sandy soil found in the Tucson area. How big are termites in actual life-size?
If you could get these termites to line up in single file and march across a U.S. dime, you'd see that if they marched along the diameter of the dime there would be at least five of them. Typical termites are 5.5 mm in length but vary in size from about 1/8" long to as much as 3/8" for the big boys.
Queen termites are bigger, over 3/4" in length excluding a pregnant queen's abdomen that, if included can make her total size 2" or even more. There are about 2800 termite species that have been identified, grouped in seven families (including the largest family, Termitidae), and it is probable that there are other species not yet classified.]
The retaining wall is 20 feet from the house, and we found tubes growing vertically in the grass too. I also got a picture of a section of dirt that has lots of those mud trails.
We've have never had termite activity inside the house. The first year that we lived here we had to have the pest control people out here several times to treat the expansion joint where the back patio meets the house.
Disturbing a termite mud tube is shown just below. They won't bite you, but some genera/species of termites will indeed bite a wood structure or its wood siding or trim.
If you disturb a mud tube and termites fall out you know for sure you've found an active colony. Unfortunately the converse is not necessarily true. If you disturb a mud tube and don't see any termites, you'll need more information and probably a more expert inspection before you know if there is ongoing termite activity or not.
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.
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
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.
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.
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.
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.
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.
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.
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.
As discussed in Best Practices Guide to Residential Construction:
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.
Also see TERMITE SHIELDS vs TERMITICIDE for 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.
Finally, 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.
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Frequently Asked Questions (FAQs)
Question: small brown granules under the siding on the concrete
(May 31, 2011) steve said:
my home is 2 yr old live in wisconsin where tge concrete porch butts up to the frame of the house i am finding small brown granuals directly under the external siding on the concrete looks like dirt but uniform insize any ideas
Steve, look for ant activity near the foundation wall.
Question: our ceiling began a popping noise, could that be due to insects
(Sept 13, 2011) Nina Claire said:
About 4 months ago our ceiling began popping, every day, usually after 12:00 noon. The house is 14 years old and we have never had this problem before. The worse part appears to be in the greatroom where the ceiling butts up against insulation and the roof. We have not experienced any cracks in the drywall. Do you know if insects can cause this type of problem. We live in Northwest Ohio where we had the hottest, driest summer in over 100 years. It seems to stop late at night. I am home during the day and the sound moves randomly around the room. I do not know where to turn. Can you possibly advise???
Nina if there is no evidence of insect attack on the building, and considering the temperature extremes you describe, I'd start addressing this ceiling popping noise with this article: TRUSS UPLIFT, ROOF that may explain what's going on.
If on the other hand, your inspection of the roof or ceiling structure found extremen rot or insect damage (risking a dangerous collapse) that would be an urgent problem needing temporary support, strutural repairs, etc. One would think that before things got that extreme you'd see roof leak stains, ceiling sagging, drywall cracks, tears, wall/ceiling separation or similar clues.
Question: can I pull down insulation, treat for powder post beetles, then re-use the insulation?
(Dec 2, 2011) pam said:
need to pull down existing paperbacked fiberglass insulation from unfinished basement ceiling to treat joists & underfloor for powderpost beetles. can i put the same insulation back up afterwards? or would the insulation contain the beetles, or doesnt it matter because they eat the wood and it has been treated. i am getting exorbitant prices for replacing the insulation and would like to re-use what I am taking down.
Pam: If you can keep the insulation batts intact and if you find that it is clean in appearance it is reasonable to re-install it. If the insulation is dirty or if it has been wet, I would replace it as you don't want to reinstall insulation that may be a reservoir of insect allergens or hidden mold. If you were seeing exorbitant prices to replace insulation, most of that cost may be the labor. Buying new insulation itself, at any home supplier or building supplier, should be quite reasonable. For example, you can buy a roll of Owens Corning EcoTouch 15"W x 39ft R19 Fiberglass Insulation (RU40) for around $30. per roll.
Question: something tiny is boring through our ceilings
(Nov 20, 2012) Anonymous said:
At my Dad's house there is something very, very tiny boring through the ceiling. He just swatted it away, but this morning is saw another one coming out of the same hole. I got it and it may be some kind of termite, but it's so tiny I had to get a magnifying glass to see it. The hole is perfectly round. There are two holes in the ceiling. Do you think it is a termite?
can't say from just your description if you saw a termite, but in general you would never see a termite voluntarily coming out into building air - they need to be protected from light and to low humidity - which is why they build mud tubes to cross between building materials or surfaces.
It might be smart to call an exterminator - let us know what you find.
Question: do termites fall out of trees onto a roof? Termite resistance of metal roofing?
We have limbs of trees hanging over the roof of our house. We've been told that termites can fall out of the tree and cause harm to our house. What if it is a tin roof.?
Thanks for the question Edward.
What you were told is inaccurate. While I have, though rarely, found termites in a building's roof structure, they entered from the ground level, not from overhanging trees, and certainly not from live trees. Termites infest dead wood not live wood.
In some climates, "drywood" termites will indeed attack structural components that are above-ground and not in direct soil contact.
In more temperate or humid climates where trees are more likely to be overhanging a building, termites will most often enter a building through soil around the structure, finding a passage through wood in contact with or close to the soil.
While I agree that a metal roof, intact and not leaking, would be resistant to insect attack from above, that's not just because insects would find boring through metal tough going. Insects don't generally bore through asphalt shingles, nor rubber roofing either. Rather, an intact metal roof should mean that water is not penetrating the roof structure. A dry building is much less inviting to wood destroying insects.
Watch out: while termites don't climb up trees and leap gloriously through the air onto your house roof nor any other roof, carpenter ants do enjoy that activity. While carpenter ants too prefer wood close to soil as an invasion pathway into a building, unlike termites carpenter ants are perfectly happy wandering around in the open, including exploring live trees and occasionally falling off, jumping off, or blowing off of such trees onto a building surface.
But if carpenter ants invade a roof, it's not because they were skydiving onto it from a tree so much as because there is a leak in the roof that has made occupying it attractive to the carpenter ants.
Finally, you should indeed trim back tree limbs overhanging and close to the roof surface, to reduce the accumulation of leaves and debris that can damage the roof or clog its gutters.
At STAINS on ROOFS we describe how to trim back trees or tree limbs overhanging a roof.
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