Carpenter ants differ from termites in that carpenter ants:

Both insects damage structural wood, but they do it for different reasons and leave different evidence, and the difference drives both the diagnosis and the treatment. Termites eat wood — they digest cellulose with the help of gut organisms — and subterranean species maintain contact with soil moisture, building shelter tubes across foundations to reach framing while staying protected. Carpenter ants do not eat wood at all; they chew it out to make nest galleries and push the residue away as coarse frass that accumulates below the entry. The practical inspection consequence is that carpenter ants are strongly associated with wood that is already moist or decayed, so finding them is also a signal to look for the leak or condensation that softened the wood in the first place. Termite galleries are typically packed with soil and follow the grain; ant galleries are clean, smooth and often cross it.

Carpenter ants excavate galleries to nest but do not consume the wood, ejecting the debris as frass. Termites consume cellulose as food, which is the fundamental behavioural difference between the two.

Subterranean termites consume cellulose and construct soil shelter tubes to maintain contact with ground moisture. Carpenter ants excavate smooth galleries for nesting and expel frass, and they preferentially attack wood already softened by moisture or decay.

Ants Evict, Termites Eat. Ants throw the sawdust out; termites keep it. Find frass, look for the leak that softened the wood.

Carpenter ant activity is a moisture finding as much as a pest finding. The report should note the conditions that attracted them, not just the insects.

• •Treating carpenter ant damage as structurally insignificant
• •Attributing cellulose consumption to carpenter ants
• •Reporting the insects without identifying the moisture that attracted them