How long should pets be kept out of the house after it has been sprayed inside and outside for carpenter ants?
This will really vary based mostly on the type of product being used. If you review our CARPENTER ANT CONTROL ARTICLE, you'll see we feature liquid concentrates, dusts, aerosols, baits and granules. Virtually all of these can be used inside or outside the home but the real important question to answer is how long should pet owners wait before they let their pets back into the treated area if any of these are used? Here are some "short" answers which should be used as a guideline. Be aware that even these suggestions can fluctuate depending on the specific product being used, where it's being used and the local weather conditions. And don't forget pets with special needs or health issues which take precedence over all else. With this understood, here are some general rules to follow that will cover most applications.
1) Liquid treatments. For anything being sprayed inside or outside the home (and this includes herbicides, fertilizers and other sprays besides just insecticides), the best answer is "until the treatment dries". Keep in mind the time required for them to dry can vary dramatically depending mostly on where you're spraying and the conditions present when you spray. For example, spraying the rug for fleas usually means a lot of spray and a high chance of people and pets coming in contact with the treatment. It's very important these areas are allowed to fully dry which in some cases will take several hours if not the whole day. Not only is it important from a safety point of view to keep people and pets off this application but it's also important so that the treatment gets a chance to work as well as it can on the target pest.
Conversely, if you were were spraying the foundation of the home only on the outside of the house and it was nice and dry outside with little humidity during and after the treatment, the application should dry quickly. In these cases most people and pets can come back to the area in as little as an hour. Remember too that most people and pets won't be touching the foundation so in this case the chance of pesticide exposure is much less compared to spraying carpeting where everyone is walking.
2) Dusts. When dusting insect nests, wall voids, attics and other spaces, the area being treated is mostly away from where pets and people should be. For this reason there is generally no wait time following the application. The only guideline here is to make sure kids and pets are away prior to and during the actual application and any cleanup. Other than that there shouldn't be any reason to keep them away for an extended period of time.
3) Aerosols. These products tend to get airborne so in general only the person doing the treatment should be present during the treatment and for some time afterward. Just how long will vary but in some cases airing out the area is suggested; in other cases it's a matter of what the label states. As a general rule a good 3-6 hours is usually enough time to wait but this is one that can vary a lot so be sure and take into consideration the type of treatment involved along with the product being used and the area being treated. Many times the label of these products will have more guidelines specific for the active ingredient being applied.
4) Baits. In general, no time is needed following applications. That's because applications should be made where people and pets won't have access. In other words, you should try to make placements above where pets can find the bait and where children can't reach them.
5) Granules. In general, very little wait time following the application unless you plan on watering them in. For those situations, waiting till the yard dries is suggested.
So to answer your question more directly, if you just "sprayed" the outside foundation of the home with a liquid, it will probably take 30 minutes or less to dry and to allow pets and kids back into the area. Inside the home will depend on whether you "sprayed" just the baseboard or the carpeting too which can cause a normal wait time of 1-2 hours become 4-8 hours.
As always, consult the label of the product you're applying to make sure there are no "special" guidelines or requirements for the product being used. Also, we STRONGLY watching our SAFETY VIDEOS which cover all you'd need to know on this subject matter.
Here are direct links to the information and products listed above:
Carpenter Ant Control Article: http://www.carpenterants.com/carpenter-ant-control
Safety Videos: http://www.carpenterants.com/product-safety