black ants in attic

I have black ants in the attic, they are large with 3 segments, apparently carpenter. They come in from some wood that is darkened though it doesn't seem moldy. This wood is near a dryer vent. The attic is on the 3rd floor. Outside inspection didn't reveal any trail of ants so I don't know how they're getting in there. The outside is stucco, no exposed wood. My concern is getting rid of them and also why that wood has deteriorated. I don't think any moisture is getting in there, though maybe the dryer vent is letting some in.
Thanks for any help.

 

The dark wood is telling you there is a moisture issue from somewhere and since the ants are in that area I would assume their presence is related.

First, before you start spraying set some ant baits. I've used Terro but from what i understand there is a specific version of that for carpenter ants.

On the outside I have found they like a bit of sun before they charge my house. Not sure if that is everywhere but time of day and climate may affect when they are active. keep watch to see where they are coming from. With stucco there is a gap behind the outer surface and it may be providing a hidden path.

Our bug pro will be along.

Bud

 

Is that picture oriented in the right direction ?
Is the dryer vent in the roof ?

That moisture looks to be from a leak.

 

I can't address the moisture source, if that's what it is.

As far as the ants go, at this point they seem to be living inside the structure so you won't see much activity outside necessarily. If using ant baits, find baits that are specific to carpenter ants. If you wish to spray, then use non-repellents that have the active ingredients: Fipronil or Imidacloprid or Phantom (trade name).

Once you solve this problem, then I'd consider preventatively treating exterior perimeter, high and low, with a fipronil based product at least several times a year. Read the label to see what it tells you. Modern day insecticide labels are instructive and helpful. Keep us posted.