Boracare would be a great option for any exposed raw wood surfaces as it will last for the life of the wood and is not in direct shot of rain. However, if you are dealing with subterranean termites, which it sounds like by your reference to mud tunnels, you would need to treat the soil around the base of the structure to eliminate the colony as the Boracare will not get rid of the ones in the ground. Termidor
is the number one product on the market for termite control and will eliminate both the termites currently in the soil around the structure and inside the structure, but will also protect it from any future infestations for at least the next 10 years. You can see our article on How To Do A Termite Treatment
for the steps you would take to eradicate the colony and protect your structure without having to lift it higher from the ground. Please let us know if you have any other questions.