Back in Sept. 2011 I was outside and happened to look up and see thousands of ants going into the vents going to my attic. I walked around my house and saw that they were going into every vent. I have never seen this before.Why were they doing this? What kind were they? And are they still in my roof or attic? Also we have termites. I suspect they have done a lot of damage. To treat and get rid of them does the old wood have to be torn away first or can it be treated and then repaired? Thanks for any help.
Ants will form scent trails for one of two reasons. Either there is a nest up in your attic or there is food. Since ants love termites, it could be they're harvesting the termites. This is not uncommon.
As to what species of ant these are? Not possible for us to say. I've seen many species target termites for food and many species live in homes and attics so the list would be quite large.
Are they still in your attic? Maybe.
Regarding the termites; no doubt they can do a lot of damage. But you didn't state if you have drywood or subterranean termites. You can read up on termites here which includes how to treat for them in case you want to do the work yourself. No doubt this will save you a lot of money:
Termite Control: http://www.termites-swarming.com/termite-control
Regarding termite damage, I've dealt with lots of homes that needed repair work. In some cases you can ignore the damage if it's not structural. And if it does include rafters, floor joists, sill plate, etc., you still may be able to leave it in place and “sister” new wood in place to take the load bearing weight. Every situation will vary and without knowing what you have damage wise, there is no way for us to tell via the internet. We'd have to do an inspection to be sure so I suggest you get a local company to check out the damage if it's structural and go from there.
As for the ants; just keep watching to see if they get active in or on the home. As soon as you see activity, you should treat. Where and what to use will vary depending on where you're seeing them.
If you start seeing them inside the home, treat with MAXFORCE ANT GEL. Placements should be made where the ants are seen. They'll quickly find it, gather it up and bring it back to their nest where they'll share it. This will ultimately kill the whole nest.
If you see them active on the outside of the home with similar trails to what you saw last fall, spray the home down with TERMIDOR. This is the same material listed in our Termite control article and can be used for both pests. Termidor works great on foraging ants that walk over treated surfaces too. So if you see them trailing out from the attic, you'll need to focus your treatment on this area as well as the gutters and even some shingles. Ants will many times nest in these areas – especially carpenter ants – and won't need to travel much further than your attic if they're nesting and harvesting food in the same region. That means if you want to use the spray, you'll have to get it where they're nesting for the treatment to work.
Here are direct links to the information and products listed above:
Ant Gel: https://bugspray.com/bait/gel/maxforce-ant-gel-1-oz