How would I protect a new house from termintes?

Creosote is mostly effective but these days is considered to be too toxic to use. People apparently get cancers from it. It also smells really awful.

It is best to keep your timbers dry and out of ground contact. Use metal stirrups set in concrete to support posts.

So long as the wood is above the soil and out of the rain, a boron-based product can perform very well with very little toxicity (or cost). If you are in a high risk area you might also apply a bifenthrin spray. Hardware stores sell these.

Ask at local lumber yards. If termites are a problem in your area, then they carry one product to deal with it. They have been around probably 50 years or more and they would not carry it if it was not in demand and did not work.

creosote is excellent,