Unless a dye was added to the Bora-Care at the time of application, you would not be able to tell if the wood in your crawlspace has been treated or not.
Ideally we would need to know specifically what pest you are treating for. Are you treating for powder post beetles? Or are you treating for drywood termites? In most cases if a wood destroying insect is found within the frame of a piece of furniture your options are as follows: Option 1- Strip down any stain or finish on the wood down to its raw natural state and apply a product like Boracare to the raw wood surface to treat it and then you can refinish as desired once dry; Option 2- If stripping the finish off isnt an option then you would need to drill holes in the needed places of the furniture and insert a product like Jecta which is an injectable form of Boracare. Both the Boracare and Jecta absorb into the wood so that as the insects inside it eat the treated wood they consume it and die from it. Both products also last for the life of the wood to protect it; Option 3- If neither of those are an option for you and you dont want to drill holes or remove the finish, then your only option would be to hire a company that has a heat treatment or fumigation treatment chamber to put the furniture within to kill all the insects within it without doing any damage to the couch.
It is best to apply Bora-Care to wood that is free from dust or other debris.
Yes, allowing Boracare to freeze can make it ineffective. It should be stored in a controlled temperature area out of direct sunlight and extreme temperatures. You also want to avoid applying any product in below freezing temperatures because the water part of the mixture can sparate and freeze.
We understand that the Boracare label can be tricky to follow. The text is referring to a gallon of undiluted solution, which makes 2 gallons of finished solution, while the chart is referring to diluted solution. So, one gallon of concentrate makes 2 gallons of finished solution when diluted at a 1:1 ratio, and that total amount of 2 gallons of finished solution covers 1,600 square feet (800 per gallon of dilution).
Powder post beetles live inside wood and can remain dormant inside wood for up to 30 years. Foggers will be unable to penetrate the wood to contact the beetles, and it certainly won’t give any sort of long term residual to product your wood when they beetles come out of their dormant stage. Bora-Care is the best product for powder post beetles. It is sprayed/painted on raw untreated wood. It will soak through to the center of the wood and protect the wood for the lifetime of the wood.