I’ve had quite a few readers ask me if railroad ties attract termites. Some people use railroad ties for landscaping or retaining walls, often near their homes. Understandably, people don’t want to place large amounts of wood in their yards if they might attract termites, which is why I get this question.
On the other hand, other people assume railroad ties with enough creosote are termite-proof, but this isn’t the case. Railroad ties can attract termites, particularly if they’re older or if they’re not installed properly.
Creosote only penetrates about a half-inch into railroad ties. It doesn’t take much of a crack to expose the railroad tie enough that termites or carpenter ants can get past the creosote. Also, the creosote leaches away over time.
In this article, I’ll explain how creosote levels and railroad tie installation steps can affect termite infestations in your railroad ties. I’ll also explain a few steps you can take to mitigate the chances of termites being attracted to your railroad ties and then moving into a nearby structure.
And before you go tearing down your railroad tie wall (or avoid building one), you should check the termite risk where you live. You’ll want to consider the termite activity where you live when deciding whether you want to use railroad ties or not. You can skip to a certain section via the table of contents. If you have a question I didn’t answer, please ask it in the comment section.
Do railroad ties coated with creosote prevent termites from eating them?
Most railroad ties you might buy for landscaping or a retaining wall were originally soaked in creosote. People often assume that creosote protects railroad ties from termites and other wood-destroying organisms.
While creosote normally does a decent job at repelling termites and other insects from eating railroad ties, it doesn’t make them termite-proof. For example, in their laboratory evaluation of the effectiveness of different wood preservatives, E. W. B. Da Costa et al. (1973) found that creosote protects wood against (Australian) subterranean termites “by a deterrent and/or repellent mechanism, rather than by a termiticidal effect.” Costa et al. conclude from their study that creosote offers over 30 years of termite protection.
But there are some important railroad tie installation steps people often skip that help prevent railroad tie insect infestations:
- Try to use newer railroad ties. The railroad ties people buy for retaining walls or landscaping are nearly always used to save money. If you’re installing railroad ties anywhere near your home, try to get ties that are in the best shape you can find. You have no clue how old second-hand railroad ties are, nor do you have any clue how much creosote remains in them. New railroad ties are normally treated to last 30 years or more, but eventually, termites and carpenter ants damage them.
- Railroad ties should be installed over a gravel base. About a 4-inch gravel base acts as a barrier between the soil and your railroad ties (it’ll also make leveling the bottom tie easier). Direct soil-to-railroad-tie contact allows more moisture to seep into your railroad ties and allows subterranean termites to find your railroad ties more easily.
How to tell if railroad ties have creosote
First, if you see a black, oily, or tar-like substance on railroad ties’ surfaces, that’s creosote. On hot days, creosote tends to seep out more than normal.
Next, if you know for certain that your railroad ties are new (or newish), then you can expect creosote to last around 30 years, assuming they are not excessively exposed to water and that you don’t cut them.
Finally, creosote has a distinct smell. It smells a bit like asphalt and is especially prevalent on hot days when it seeps to the surface of ties.
If you see a black, sappy, tar-like substance on your railroad ties or smell something like asphalt, those ties likely have ample creosote left protecting them. It’s tough to say for sure, though, because one part of a railroad tie might have sufficient creosote for protection while another portion does not (e.g., the exposed top might well protected while the bottom of the tie, buried in the soil, lost all protection).
Termites or carpenter ants only need a small entryway into a railroad tie to start eating it from the inside (where there’s no creosote) and work their way outward (where the creosote layer is).
How to tell if my railroad ties have termites in them
It’s difficult to know if your railroad ties are being attacked because if termites get into your railroad ties, they’ll eat them from the inside out. So, to detect termite activity in or near your railroad ties, keep an eye out for the following evidence of termite activity:
- Termite mud tubes: Normally, subterranean termites can find their way from the soil straight into your railroad ties without building protective mud tubes because railroad ties usually lie in such a way where at least one surface touches the soil. Still, if you use spot termite mud tubes traversing up your railroad tie retaining wall, for example, your ties are probably being eaten by termites.
- Termite swarmers: If you notice flying termite swarmers emerging from or nearby your railroad ties, that means there’s a reproductively mature termite colony near your railroad ties. Chances are they were feeding on your railroad ties, so you’ll want to investigate further. You can do that with a tap test. If you need to learn how to identify flying termites, read this.
- Tap test with a screwdriver: Maybe once or twice a year, go along the length of your railroad ties and tap them with a screwdriver. If a railroad tie has been significantly hollowed out by termite damage, you’ll notice a difference in sound the tapping sound. In other words, a solid portion of a railroad tie will sound different than a hollowed-out section.
You might also notice a sudden increase in birds, lizards, toads, or frogs around your wood railroad ties. If you see this, try to notice if they’re eating something. It’s not unusual for termite swarmers emerging from railroad tie walls to attract termite predators looking for an easy meal.
What should I do if I find termites in my railroad tie wall or edging?
If you find termites in your railroad tie wall or landscaping, you should consider how close the railroad tie wall or landscaping is to the nearest building.
If the railroad ties are close enough to a structure, subterranean termites could spread from the railroad ties to the structure. When this happens, people rarely notice since subterranean termites tend to stay hidden under the soil.
If your home is treated for subterranean termites (usually this is via a termiticide liquid barrier and/or termite monitoring bait stations), then your home is likely safe.
But, if your termite liquid barrier has been disturbed in any way (this happens often when people landscape near their foundations), then you’re at risk of the termites finding their way into your home.
I’d contact a termite control professional and ask them to inspect your railroad tie retaining wall or landscaping and your home. They’ll advise you on what to do next.
Typically, people don’t treat railroad tie walls for active termite infestation because railroad tie walls are only expected to last so long (around 30 years). If you have a termite-infested railroad tie retaining wall, your options are usually the following:
- Let termites eat your railroad tie wall: If your railroad tie wall is positioned far enough away from your home that if it fell, it shouldn’t damage your home or other property, you could let the termites feast away until your railroad tie wall is nearly destroyed. After that, you could tear it out and build a new wall with stone or concrete. If you go this route, ensure you’re home has the recommended termite prevention strategies in place so the termites in the railroad ties don’t find their way into your home or business.
- Replace your railroad tie wall with a stone wall right away: Some people don’t want to risk their infested railroad tie retaining wall caving and damaging their home or some other property. Or, they don’t want to risk the termites finding their way into their home. If you’re in either of these camps, it makes sense to replace your infested railroad tie with a stone or concrete wall as soon as feasible.
How to get rid of railroad ties
If you decide you want to swap out your railroad tie landscaping or wall for stone, the EPA states that you can usually drop off old railroad ties at your local landfill. But call ahead and check with them because every state and city has different regulations. Also, it’s best to wear a long-sleeved shirt, pants, and gloves to prevent creosote from getting on your skin. And a respirator if you have to cut into any creosote-soaked railroad ties during the removal.
Summary of termites and railroad ties
TL;DR, termites can be attracted to railroad ties, particularly when they are older and their creosote has leached out.
If you really want to use railroad ties for landscaping or a retaining wall, keep them as far away from buildings as feasible and inspect them once or twice a year for termite activity.
Additionally, when you install them, install them on a gravel layer around 4 inches thick and minimize cutting or splitting your ties because doing so penetrates the protective creosote layer.
Finally, understand that even brand-new railroad ties only have around a 30-year shelf life. After that, the creosote has leached out enough to where railroad ties have little protection against termites and other wood-destroying organisms.
