Since the structure of your custom home will have to withstand the added weight of the addition, new support beams will need to be installed to replace the damaged section.
It is best to conduct a professional termite inspection before a home improvement of this scale, which should cost around $ 50 – $ 150.
The only caveat for this rule of thumb is with a kitchen addition where electrical, gas, and water will need to be reconfigured, and that can prove costly.