You should drill whatever size hole you need based on what you have available to inject the Bora-care with. Typically if you have an injection piece of equipment, 1/4 inch or 1/8 inch holes are used. Please see this technical bulletin from the manufacturers of Bora-Care that explains about drilling and injecting into wood. See page 5 and it will give specifics about the drill pattern, etc.
Yes, you can apply Bora-Care to pressure treated wood as long as there is not any kind of paint, stain, or water sealant already on the wood. Be sure you apply Boracare at a 1:1 diluation ratio with water for active insect infestations. You should then apply a water sealant to the wood after the Boracare has dried for best results.
Bora-Care is a very safe product and it is considered a green product as well. Typically, it takes about an hour for the surface of the wood to dry. After the application has dried completely, it should be perfectly fine for children and pets to re-enter the house. Bora-Care is a wood treatment product only and should have no effect on concrete. If you are looking for peace-of-mind and protection when applying professional pest control products, then the Basic Safety Kit is for you
Boracare does need to be diluted depending on what you are intending to use the product for. For an active infestation of a wood destroying insect, you will use 1 gallon of hot water with 1 gallon of Boracare. The percentage of active ingredient is 23% in that dilution.
2:1 parts water to Boracare – 16% - foaming or misting application for termites or carpenter ants; hardwood floors for some wood-infesting beetles
3:1 parts water to Boracare – 13% - remedial control of Fungi and Algae on wood less than 4 inches thick
5:1 parts water to Boracare – 9% - most preventative or pre-construction treatments.