Per the product label, you can inject or dust Timbor at a rate of 0.5 oz per square foot when treating wall voids for insects such as carpenter ants. If you are mixing Timbor in water and creating a foam with a foaming solution and foamer, then you would use 1.5 oz of Timbor per gallon of water and use a high expansion foam. Keep in mind that drilling into and injecting a product like Timbor into all your wall voids is a tedious and labor-intensive application that is often best left to professionals. We have a great Carpenter Ant Treatment Guide here that may better assist you.
